Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a Scheme depicting the experimental time line. Quantification of heart weight/tibia length (HW/TL) ratio, n = 7/group, **** p < 0.0001 ( b ), lung weight/tibia length (LW/TL) ratio, n = 7/group, *** p = 0.001 ( c ), left ventricular ejection fraction, n = 5/sham group and n = 8/TAC group, **** p < 0.0001 ( d ), quadriceps muscle weight, n = 7/group, **** p < 0.0001 ( e ), gastrocnemius muscle weight n = 7/group, *** p = 0.0003 ( f ), triceps brachii muscle weight, n = 7/group, ** p = 0.0051 ( g ), plantaris muscle weight, n = 7/group, * p = 0.0175 ( h ), soleus muscle weight, n = 7/group, * p = 0.0126 ( i ), and course of body weight (BW) during the experiment until 12 weeks after TAC or sham surgery, n = 4/sham group and n = 5/TAC group, *** p = 0.0001 ( j ). Inguinal fat weight, ** p = 0.0021 ( k ) in the group of mice that was analyzed by MRI to determine the amount of abdominal fat, * p = 0.0273 ( l ), psoas muscle, * p = 0.0499 ( m ) and autochthonal muscle, * p = 0.0412 ( n ) 12 week after sham or TAC surgery, n = 4/group. Example MRI cross-sections are shown in ( o ). The red arrows indicate abdominal fat. Scale bar: 5 mm. Cross-sectional fiber area type IIb, ** p = 0.0028 for 1000–2000 µm 2 ; * p = 0.0254 for 2000–3000 µm 2 and * p = 0.0125 for 3000–4000 µm 2 of muscle fiber area from sham vs. TAC group ( p ), and type IId, **** p < 0.0001 of fiber area <1000 µm 2 ( q ) of quadriceps muscles 12 weeks after sham or TAC surgery, n = 4/group, analyzed from microscopic pictures with ATPase staining (pH 4.2) as shown in ( r ). Scale bar: 300 μm. s Ostn (Musclin) mRNA levels in different organs 12 weeks after sham or TAC surgery, n = 3/group. t Immunoblot (the size of the proteins is indicated in kDa) and immunofluorescence staining ( u ) showing Musclin protein levels in the quadriceps muscle of sham and TAC mice. Scale bar: 100 μm. v Musclin plasma levels in mice 12 weeks after sham or TAC surgery, n = 10 for sham and n = 9 for TAC, * p = 0.0115. w Time course (2, 6 and 12 weeks after TAC or sham surgery), n = 4/group, showing the decline of Ostn mRNA levels in the gastrocnemius, triceps, *** p = 0.0007 6 weeks and * p = 0.0241 12 weeks, in quadriceps muscles, ** p = 0.002 by 12 weeks after TAC compared to sham mice. Data are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 as determined by Kruskal–Wallis test with Dunn’s multiple comparisons test (for s ) or two-tailed Student’s t test (all other numerical data containing panels) or p value determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test ( p , q ). Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Muscles, Staining, Western Blot, Immunofluorescence, Clinical Proteomics, Two Tailed Test

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a OSTN mRNA levels in vastus lateralis muscle biopsy samples from control individuals ( n = 9) and from patients with sarcopenia ( n = 6) or cachexia ( n = 5), * p = 0.0236. b Concentrations of Musclin protein in the serum of healthy control individuals ( n = 56) and of patients with severe aortic stenosis ( n = 26), * p = 0.0403 ( c ) and of the same patients excluding the ones with diabetes mellitus ( n = 18), ** p = 0.0044. Data are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01 as determined by ANOVA followed by the Holms–Sidak’s multiple comparisons test ( a ) and the two-tailed Mann–Whitney test ( b , c ). Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Control, Two Tailed Test, MANN-WHITNEY

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Clinical characteristics of the patients (all male) with aortic stenosis.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques:

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a Scheme depicting the experimental time line. b mRNA level of Ostn (Musclin) 9 weeks after TAC and intramuscular application of AAV6 control (Co) or AAV6 Musclin (Mu) vector ( n = 12/group), *p = 0.036 ( c ) Immunoblot for Musclin 9 weeks after TAC and intramuscular application of AAV6 Co or AAV6 Mu. GAPDH, Actin and Tubulin are loading controls. The size of the proteins is indicated in kDa. d Musclin plasma levels in AAV6 Co ( n = 21) or AAV6 Mu ( n = 22) treated mice, ** p = 0.0029. e Heart weight/tibia length (HW/TL) ratio in AAV6 Co (sham n = 5, TAC n = 7) or AAV6 Mu (sham n = 5, TAC n = 6) treated mice 9 weeks after sham or TAC surgery, *** p = 0.0004, * p = 0.0316. f – h Echocardiographic ejection fraction 3 weeks (all sham n = 5/group, TAC AAV6 Co n = 17, TAC AAV6 Mu n = 15), **** p < 0.0001, ** p = 00015 and * p = 0.0293 ( f ), and 6 weeks after surgery, **** p < 0.0001 in AAV6 Control and AAV6 Musclin groups for sham vs. TAC surgery, ** p = 0.0021 ( g ), and 9 weeks after surgery, **** p < 0.0001, *** p = 0.0006 and ** p = 0.0051 ( h ). Cardiac systolic contractility (dp/dt max, i ), * p = 0.0122 and diastolic relaxation (dp/dt min, j ), * p = 0.0164 determined by left ventricular catheterization in the indicated mice (all sham n = 5/group, TAC AAV6 Co n = 9, AAV6 Mu n = 8) 9 weeks after sham or TAC surgery. Representative Sirius red-stained heart sections ( k ) and quantified myocardial fibrotic area ( l ) and of mice treated as shown (all sham n = 5/group, all TAC n = 8/group, 9 weeks after surgery), ** p = 0.0093 and * p = 0.0206. Scale bar: 500 µm. m – p qPCR analysis of the indicated fibrosis genes 9 weeks after sham or TAC surgery (sham AAV6 Co n = 5, sham AAV6 Mu n = 4, TAC AAV6 Co n = 7, TAC AAV6 Mu n = 8), ** p = 0.0064 ( m ), ** p = 0.0081 ( n ), * p = 0.0248 ( o ), * p = 0.0369 ( p ). q Mature CNP plasma levels in AAV6 Co or AAV6 Mu treated mice 3 weeks after TAC surgery ( n = 4/group), * p = 0.0462. Data are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 as determined by two-tailed Student’s t test ( d , q ) or by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (other bar graphs). Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Control, Plasmid Preparation, Western Blot, Clinical Proteomics, Staining, Two Tailed Test

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a Scheme depicting the Musclin ( Ostn ) knockout (KO) targeting strategy. The exon 3 of the Ostn gene is floxed and b deleted through the crossing with double transgenic mice that express Cre recombinase selectively in skeletal muscle and only following doxycycline treatment. c Scheme depicting the experimental time line. d qPCR analysis of Ostn mRNA in the quadriceps muscle and the heart 2 weeks after TAC or sham surgery in KO vs. littermate control (WT) mice (all sham n = 8/group, all TAC n = 12/group), * p = 0.0359. e Immunoblot for Musclin in the quadriceps muscle and the heart 2 weeks after TAC or sham surgery in WT vs. KO mice. GAPDH and Tubulin are loading controls. The size of the proteins is indicated in kDa. f Immunofluorescence staining for Musclin in the quadriceps muscle of WT and KO mice. Scale bar: 100 μm. g Musclin plasma levels of WT ( n = 21) and KO mice ( n = 16), ** p = 0.0014. h Ostn mRNA levels in the indicated organs of the mice as shown (n = 7/group), ** p = 0.0027. Quantification of the heart weight/tibia length ratio (HW/TL, **** p < 0.0001) ( i ), echocardiographic ejection fraction, ** p = 0.0018 and **** p < 0.0001, * p = 0.0445 ( j ), systolic contractility ( k , by LV-catheter, * p = 0.0334) and diastolic relaxation ( l , by LV-catheter, ** p = 0.0094) in mice treated as indicated in ( c ), (for HW/TL ratio and for echocardiography: all sham n = 6/group, TAC WT n = 18, TAC KO n = 14; for LV-catheter: n = 8/group). m , n Myocardial fibrotic area with representative Sirius red-stained myocardial sections of WT and KO mice treated as indicated (all sham n = 8/group, TAC WT n = 9, TAC KO n = 10, ** p = 0.0033 in WT and **** p < 0.0001 in KO mice after sham vs. TAC surgery, ** p = 0.0033 in WT vs. KO mice after TAC). Scale bar: 500 µm. o Mature CNP peptide plasma levels in the indicated mice ( n = 8/group, * p = 0.0312). Data are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, **** p < 0.0001 determined by two-tailed Student’s t test ( g , h , o ) or one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (other bar graphs). Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Knock-Out, Transgenic Assay, Control, Western Blot, Immunofluorescence, Staining, Clinical Proteomics, Two Tailed Test

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a Scheme depicting the proposed mechanism of augmented cardiomyocyte contractility by Musclin. Scheme ( b ) and results ( c ) of the NPR-C/Musclin/CNP competition assay. Increasing levels of recombinant CNP led to Musclin displacement from NPR-C ( n = 2 per CNP concentration, mean values are shown). d Representative fluorescence images from Hek293 cells with and without transfection of the NPR-C-GFP construct. Scale bar 100 µm. e CNP concentrations (determined by ELISA) in the supernatant of transfected and untransfected Hek293 cells (as shown in d ) 1 h after treatment as indicated ( n = 4/condition, * p = 0.0104). f Representatives traces of sarcomere length and g quantification of cell shortening (from traces as shown in f ) in isolated wild-type mouse cardiomyocytes treated with recombinant CNP or Musclin as indicated ( n = 13 cardiomyocytes/group, ** p = 0.0016 for Vehicle vs. CNP (10 nM), ** p = 0.0012 for CNP (10 nM) vs. CNP (100 nM) and ** p = 0.0026 for CNP (100 nM) vs. CNP (100 nM) plus Musclin (10 nM)). h Representative Fura-2 Ca 2+ traces and quantitative analysis ( i ) in cardiomyocytes treated as described for ( f ) ( n = 12 cells/group, * p = 0.0168 for Vehicle vs. CNP and * p = 0.0169 for cells stimulated with CNP vs. Musclin). j – l Cell shortening in cardiomyocytes treated as indicated from wild-typ (WT) (vehicle cardiomyocytes n = 46, after CNP stimulation n = 24, treated with Musclin n = 21, cardiomyocytes treated with CNP and Musclin n = 16 cells), **** p < 0.0001, * p = 0.0278 and ** p = 0.0091 ( j ), cardiomyocyte-specific Npr1 knockout (vehicle-treated cardiomyocytes n = 25, after CNP stimulation n = 27, cardiomyocytes treated with Musclin n = 25, cardiomyocytes treated with CNP and Musclin n = 22, * p = 0.01 and *** p = 0.0003 ( k ), and global Npr2 knockout mice (vehicle-treated cardiomyocytes n = 40, after CNP stimulation n = 39, treated with Musclin n = 31, cardiomyocytes treated with CNP and Musclin n = 28 cells) ( l ). Data in bar graphs are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 determined by Kruskal–Wallis with Dunn’s multiple comparisons test ( e ) or by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (all other panels). Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Competitive Binding Assay, Recombinant, Concentration Assay, Fluorescence, Transfection, Construct, Enzyme-linked Immunosorbent Assay, Isolation, Knock-Out

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Cardiomyocytes were isolated from either cGES-DE5 transgenic (for cGMP measurements) or from Epac2-camps (for cAMP measurements) transgenic mice. a , b Fluorescence resonance energy transfer (FRET)-based measurements of cGMP in single cultured cardiomyocytes ( n = 7 cells). The stimulation with CNP and Musclin was conducted as indicated. Representative traces ( a ) and a quantitative analysis ( b ) are shown, * p = 0.0342. c , d FRET-based measurements of cAMP in single cardiomyocytes treated as indicated ( n = 13 cells). The cells were stimulated with Isoproterenol (Iso), CNP and subsequently Musclin as indicated. The graph illustrates the FRET-responses to CNP in % of the maximal Iso effect. Representative traces ( c ) and a quantitative analysis ( d ) are shown, ** p = 0.0019. e – h ELISA-based measurements of cGMP and cAMP in cultured cardiomyocytes under the indicated conditions from wild-typ (WT) ( e , g ), ** p = 0.0012 for vehicle-treated cells vs. stimulated with CNP (100 nM), **** p < 0.0001 for cells stimulated with Musclin vs. with CNP (100 nM) and Musclin, ** p = 0.0013 for cells treated with CNP (100 nM) vs. cells stimulated with Musclin and CNP (100 nM) ( e ), * p = 0.034 ( g ) and global Npr2 knockout mice ( f , h ) (for cGMP measurement n = 4/condition and for cAMP n = 3/condition). i , j FRET-based measurements of cAMP in single WT cardiomyocytes treated as indicated. Representative traces ( i ) and a quantitative analysis ( j ) are shown ( n = 6 cells without Musclin treatment and n = 8 cells with Musclin). k Representatives traces of sarcomere length and l quantification of cell shortening (from traces as shown in k ) in isolated wild-type mouse cardiomyocytes treated as indicated ( n = 9 cardiomyocytes per group, * p = 0.017). Cilostamide was used as PDE3 inhibitor. Data in bar graphs are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, **** p < 0.0001 determined by two-tailed Student’s t test ( b , d , j ), one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test ( e , f , l ) or by Kruskal–Wallis with Dunn’s multiple comparisons test ( g , h ). n.s. denotes “not significant”. Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Isolation, Transgenic Assay, Fluorescence, Förster Resonance Energy Transfer, Cell Culture, Enzyme-linked Immunosorbent Assay, Knock-Out, Two Tailed Test

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Cardiomyocyte cGMP ( a , * p = 0.0268), ( c , * p = 0.048) and cAMP ( b , * p = 0.029), ( d , * p = 0.025) levels (determined by ELISA) after sham and TAC surgery in control (WT) and Musclin knockout (KO) mice after TAC, as well as in Sham and TAC operated mice treated either with AAV6 Control (Co) or AAV6 Musclin (Mu) (WT sham n = 5, WT TAC n = 9, KO TAC n = 10, sham AAV6 Co n = 4, sham AAV6 Mu n = 3, TAC AAV6 Co n = 6, TAC AAV6 Mu n = 7). Immunoblots for the indicated proteins (GAPDH as loading control) from cardiac protein lysate 3 days ( e ), cardiomyocyte protein lysate 14 days ( f ) or cardiac protein lysate 9 weeks ( g ) after TAC or sham surgery in WT or KO mice or in mice treated with AAV6 Co or AAV6 Mu as shown. The size of the proteins is indicated in kDa. Data in bar graphs are shown as mean ± standard error of the mean (SEM). * p < 0.05, determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test. Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: Enzyme-linked Immunosorbent Assay, Control, Knock-Out, Western Blot

Journal: Nature Communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: a Measurement of cardiac fibroblast proliferation by BrDU incorporation ELISA with addition of CNP and/or Musclin ( n = 5/condition, ** p = 0.0039 for vehicle vs. CNP, ** p = 0.0019 for vehicle vs. musclin and *** p = 0.0002). b Assessment of cardiac fibroblast migration through detection of recovery of a scratch wound after 4 h during stimulation as indicated ( n = 6/condition, ** p = 0.0023, *** p = 0.0003 for vehicle-treated cells vs. stimulated with Musclin, and *** p = 0.0005 vs. cells stimulated with CNP and Musclin). c – e Measurement of cardiac fibroblast proliferation by BrDU incorporation ELISA under the indicated conditions ( c – e ) ( n = 6/condition, except siNPR2 treatment n = 7); * p = 0.0103 for siControl cells, vehicle treated vs. stimulated with CNP, ** p = 0.0016 vs. stimulated with Musclin and *** p = 0.0001 vs. stimulated with CNP and Musclin, * p = 0.0103 for siNPR1 cells, vehicle treated vs. stimulated with CNP, **** p < 0.0001 vs. stimulated with Musclin and vs. stimulated with CNP and Musclin ( c ); * p = 0.0243, ** p = 0.0055 and *** p = 0.0003 ( d ); ** p = 0.0021 for siControl cells, vehicle treated vs. stimulated with CNP, ***p = 0.0002 vs. stimulated with Musclin, and **** p < 0.0001 vs. treated with both CNP and Musclin, *** p = 0.0002 for siNPR3 cells, vehicle treated vs. stimulated with CNP, **** p < 0.0001 vs. treated with Musclin and vs. cells treated with both CNP and Musclin ( e ). Assessment of cardiac fibroblast migration by scratch assay in cardiac fibroblasts ( n = 6/condition) treated with siRNA, CNP and Musclin as indicated ( f – h ), * p = 0.036 for siControl cells, vehicle treated vs. treated with CNP, *** p < 0.0001 vs. Musclin and vs. stimulated with CNP and Musclin, * p = 0.046 for siNPR1 cells, vehicle treated vs. stimulated with CNP, ** p = 0.0013 vs. Musclin and **** p < 0.0001 vs. cells treated with both CNP and Musclin ( f ); * p = 0.0148 for siControl cells, vehicle treated vs. treated with CNP, ** p = 0.0013, and * p = 0.0148 between siControl and siNPR2 cells treated with both CNP and Musclin ( g ); * p = 0.0162 for siControl cells, vehicle treated vs. cells stimulated with CNP, ** p = 0.0042 vs. cells treated with Musclin and *** p = 0.0004 vs. cells stimulated with both CNP and Musclin, * p = 0.0162 for siNPR3 cells, vehicle treated vs. stimulated with CNP or Musclin and *** p = 0.0002 vs. stimulated with Musclin and CNP, *** p = 0.0005 for siControl cells treated with Musclin und CNP vs. siNPR3 cells stimulated with Musclin and CNP, *** p = 0.0008 for vehicle-treated siControl cells vs. vehicle-treated siNPR3 cells ( h ). i , j Assessment of cardiac fibroblast proliferation and migration after stimulation with Musclin, CNP or the PKG inhibitor DT3 as indicated (for proliferation n = 7/condition, ** p = 0.0018 for vehicle vs. Musclin treated cells and * p = 0.016 for cells stimulated with Musclin vs. cells treated with Musclin and DT3 ( i ), and for migration n = 4/condition, ** p = 0.0043 for vehicle-treated cells vs. stimulated with Musclin, *** p = 0.0005 for cells treated with Musclin vs. treated with DT3 ( j )). k Immunoblot from cardiac fibroblasts’ protein lysate for the indicated proteins after stimulation as indicated. GAPDH was used as loading control. The size of the proteins is indicated in kDa. Data in bar graphs are shown as mean ± standard error of the mean (SEM). * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test. Mu stands for Musclin. Source data are provided as a source data file.

Article Snippet: Human serum Musclin concentrations were determined by the human Musclin ELISA kit (Cusabio, # CSB-E12021h) according to manufacturer’s instructions in male healthy blood donors or male patients suffering from severe aortic stenosis before aortic valve replacement was conducted (the patient characteristics are shown in Table ).

Techniques: BrdU Incorporation Assay, Enzyme-linked Immunosorbent Assay, Migration, Wound Healing Assay, Western Blot, Control

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 1 Musclin expression decreases in wasting skeletal muscles during advanced heart failure. a Scheme depicting the experimental time line. Quantification of heart weight/tibia length (HW/TL) ratio, n = 7/group, ****p < 0.0001 (b), lung weight/tibia length (LW/TL) ratio, n = 7/group, ***p = 0.001 (c), left ventricular ejection fraction, n = 5/sham group and n = 8/TAC group, ****p < 0.0001 (d), quadriceps muscle weight, n = 7/group, ****p < 0.0001 (e), gastrocnemius muscle weight n = 7/group, ***p = 0.0003 (f), triceps brachii muscle weight, n = 7/group, **p = 0.0051 (g), plantaris muscle weight, n = 7/group, *p = 0.0175 (h), soleus muscle weight, n = 7/group, *p = 0.0126 (i), and course of body weight (BW) during the experiment until 12 weeks after TAC or sham surgery, n = 4/sham group and n = 5/TAC group, ***p = 0.0001 (j). Inguinal fat weight, **p = 0.0021 (k) in the group of mice that was analyzed by MRI to determine the amount of abdominal fat, *p = 0.0273 (l), psoas muscle, *p = 0.0499 (m) and autochthonal muscle, *p = 0.0412 (n) 12 week after sham or TAC surgery, n = 4/group. Example MRI cross-sections are shown in (o). The red arrows indicate abdominal fat. Scale bar: 5 mm. Cross-sectional fiber area type IIb, **p = 0.0028 for 1000–2000 µm2; *p = 0.0254 for 2000–3000 µm2 and *p = 0.0125 for 3000–4000 µm2 of muscle fiber area from sham vs. TAC group (p), and type IId, ****p < 0.0001 of fiber area <1000 µm2 (q) of quadriceps muscles 12 weeks after sham or TAC surgery, n = 4/group, analyzed from microscopic pictures with ATPase staining (pH 4.2) as shown in (r). Scale bar: 300 μm. s Ostn (Musclin) mRNA levels in different organs 12 weeks after sham or TAC surgery, n = 3/group. t Immunoblot (the size of the proteins is indicated in kDa) and immunofluorescence staining (u) showing Musclin protein levels in the quadriceps muscle of sham and TAC mice. Scale bar: 100 μm. v Musclin plasma levels in mice 12 weeks after sham or TAC surgery, n = 10 for sham and n = 9 for TAC, *p = 0.0115. w Time course (2, 6 and 12 weeks after TAC or sham surgery), n = 4/group, showing the decline of Ostn mRNA levels in the gastrocnemius, triceps, ***p = 0.0007 6 weeks and *p = 0.0241 12 weeks, in quadriceps muscles, **p = 0.002 by 12 weeks after TAC compared to sham mice. Data are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 as determined by Kruskal–Wallis test with Dunn’s multiple comparisons test (for s) or two-tailed Student’s t test (all other numerical data containing panels) or p value determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (p, q). Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Expressing, Muscles, Staining, Western Blot, Clinical Proteomics, Two Tailed Test

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 2 Muscle OSTN mRNA and Musclin serum levels are reduced in patients with heart failure. a OSTN mRNA levels in vastus lateralis muscle biopsy samples from control individuals (n = 9) and from patients with sarcopenia (n = 6) or cachexia (n = 5), *p = 0.0236. b Concentrations of Musclin protein in the serum of healthy control individuals (n = 56) and of patients with severe aortic stenosis (n = 26), *p = 0.0403 (c) and of the same patients excluding the ones with diabetes mellitus (n = 18), **p = 0.0044. Data are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01 as determined by ANOVA followed by the Holms–Sidak’s multiple comparisons test (a) and the two-tailed Mann–Whitney test (b, c). Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Control, Two Tailed Test, MANN-WHITNEY

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 3 AAV6-mediated overexpression of Musclin in skeletal muscle attenuates left ventricular dysfunction and myocardial fibrosis during long-term pressure overload. a Scheme depicting the experimental time line. b mRNA level of Ostn (Musclin) 9 weeks after TAC and intramuscular application of AAV6 control (Co) or AAV6 Musclin (Mu) vector (n = 12/group), *p = 0.036 (c) Immunoblot for Musclin 9 weeks after TAC and intramuscular application of AAV6 Co or AAV6 Mu. GAPDH, Actin and Tubulin are loading controls. The size of the proteins is indicated in kDa. d Musclin plasma levels in AAV6 Co (n = 21) or AAV6 Mu (n = 22) treated mice, **p = 0.0029. e Heart weight/tibia length (HW/TL) ratio in AAV6 Co (sham n = 5, TAC n = 7) or AAV6 Mu (sham n = 5, TAC n = 6) treated mice 9 weeks after sham or TAC surgery, ***p = 0.0004, *p = 0.0316. f–h Echocardiographic ejection fraction 3 weeks (all sham n = 5/group, TAC AAV6 Co n = 17, TAC AAV6 Mu n = 15), ****p < 0.0001, **p = 00015 and *p = 0.0293 (f), and 6 weeks after surgery, ****p < 0.0001 in AAV6 Control and AAV6 Musclin groups for sham vs. TAC surgery, **p = 0.0021 (g), and 9 weeks after surgery, ****p < 0.0001, ***p = 0.0006 and **p = 0.0051 (h). Cardiac systolic contractility (dp/dt max, i), *p = 0.0122 and diastolic relaxation (dp/dt min, j), *p = 0.0164 determined by left ventricular catheterization in the indicated mice (all sham n = 5/group, TAC AAV6 Co n = 9, AAV6 Mu n = 8) 9 weeks after sham or TAC surgery. Representative Sirius red-stained heart sections (k) and quantified myocardial fibrotic area (l) and of mice treated as shown (all sham n = 5/group, all TAC n = 8/group, 9 weeks after surgery), **p = 0.0093 and *p = 0.0206. Scale bar: 500 µm. m–p qPCR analysis of the indicated fibrosis genes 9 weeks after sham or TAC surgery (sham AAV6 Co n = 5, sham AAV6 Mu n = 4, TAC AAV6 Co n = 7, TAC AAV6 Mu n = 8), **p = 0.0064 (m), **p = 0.0081 (n), *p = 0.0248 (o), *p = 0.0369 (p). q Mature CNP plasma levels in AAV6 Co or AAV6 Mu treated mice 3 weeks after TAC surgery (n = 4/group), *p = 0.0462. Data are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 as determined by two-tailed Student’s t test (d, q) or by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (other bar graphs). Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Over Expression, Control, Plasmid Preparation, Western Blot, Clinical Proteomics, Staining, Two Tailed Test

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 4 Adult induced skeletal muscle-specific Musclin deficient mice show exaggerated LV-dysfunction and myocardial fibrosis after short-term TAC. a Scheme depicting the Musclin (Ostn) knockout (KO) targeting strategy. The exon 3 of the Ostn gene is floxed and b deleted through the crossing with double transgenic mice that express Cre recombinase selectively in skeletal muscle and only following doxycycline treatment. c Scheme depicting the experimental time line. d qPCR analysis of Ostn mRNA in the quadriceps muscle and the heart 2 weeks after TAC or sham surgery in KO vs. littermate control (WT) mice (all sham n = 8/group, all TAC n = 12/group), *p = 0.0359. e Immunoblot for Musclin in the quadriceps muscle and the heart 2 weeks after TAC or sham surgery in WT vs. KO mice. GAPDH and Tubulin are loading controls. The size of the proteins is indicated in kDa. f Immunofluorescence staining for Musclin in the quadriceps muscle of WT and KO mice. Scale bar: 100 μm. g Musclin plasma levels of WT (n = 21) and KO mice (n = 16), **p = 0.0014. h Ostn mRNA levels in the indicated organs of the mice as shown (n = 7/group), **p = 0.0027. Quantification of the heart weight/tibia length ratio (HW/TL, ****p < 0.0001) (i), echocardiographic ejection fraction, **p = 0.0018 and ****p < 0.0001, *p = 0.0445 (j), systolic contractility (k, by LV-catheter, *p = 0.0334) and diastolic relaxation (l, by LV-catheter, **p = 0.0094) in mice treated as indicated in (c), (for HW/TL ratio and for echocardiography: all sham n = 6/group, TAC WT n = 18, TAC KO n = 14; for LV-catheter: n = 8/group). m, n Myocardial fibrotic area with representative Sirius red-stained myocardial sections of WT and KO mice treated as indicated (all sham n = 8/group, TAC WT n = 9, TAC KO n = 10, **p = 0.0033 in WT and ****p < 0.0001 in KO mice after sham vs. TAC surgery, **p = 0.0033 in WT vs. KO mice after TAC). Scale bar: 500 µm. o Mature CNP peptide plasma levels in the indicated mice (n = 8/group, *p = 0.0312). Data are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ****p < 0.0001 determined by two-tailed Student’s t test (g, h, o) or one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (other bar graphs). Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Knock-Out, Transgenic Assay, Control, Western Blot, Staining, Clinical Proteomics, Two Tailed Test

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 5 Musclin augments cardiomyocyte contractility by enhancement of CNP/NPR-B signaling. a Scheme depicting the proposed mechanism of augmented cardiomyocyte contractility by Musclin. Scheme (b) and results (c) of the NPR-C/Musclin/CNP competition assay. Increasing levels of recombinant CNP led to Musclin displacement from NPR-C (n = 2 per CNP concentration, mean values are shown). d Representative fluorescence images from Hek293 cells with and without transfection of the NPR-C-GFP construct. Scale bar 100 µm. e CNP concentrations (determined by ELISA) in the supernatant of transfected and untransfected Hek293 cells (as shown in d) 1 h after treatment as indicated (n = 4/condition, *p = 0.0104). f Representatives traces of sarcomere length and g quantification of cell shortening (from traces as shown in f) in isolated wild-type mouse cardiomyocytes treated with recombinant CNP or Musclin as indicated (n = 13 cardiomyocytes/group, **p = 0.0016 for Vehicle vs. CNP (10 nM), **p = 0.0012 for CNP (10 nM) vs. CNP (100 nM) and **p = 0.0026 for CNP (100 nM) vs. CNP (100 nM) plus Musclin (10 nM)). h Representative Fura-2 Ca2+ traces and quantitative analysis (i) in cardiomyocytes treated as described for (f) (n = 12 cells/group, *p = 0.0168 for Vehicle vs. CNP and *p = 0.0169 for cells stimulated with CNP vs. Musclin). j–l Cell shortening in cardiomyocytes treated as indicated from wild-typ (WT) (vehicle cardiomyocytes n = 46, after CNP stimulation n = 24, treated with Musclin n = 21, cardiomyocytes treated with CNP and Musclin n = 16 cells), ****p < 0.0001, *p = 0.0278 and **p = 0.0091 (j), cardiomyocyte-specific Npr1 knockout (vehicle-treated cardiomyocytes n = 25, after CNP stimulation n = 27, cardiomyocytes treated with Musclin n = 25, cardiomyocytes treated with CNP and Musclin n = 22, *p = 0.01 and ***p = 0.0003 (k), and global Npr2 knockout mice (vehicle- treated cardiomyocytes n = 40, after CNP stimulation n = 39, treated with Musclin n = 31, cardiomyocytes treated with CNP and Musclin n = 28 cells) (l). Data in bar graphs are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 determined by Kruskal–Wallis with Dunn’s multiple comparisons test (e) or by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (all other panels). Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Competitive Binding Assay, Recombinant, Concentration Assay, Transfection, Construct, Enzyme-linked Immunosorbent Assay, Isolation, Knock-Out

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 6 Musclin increases cGMP and cAMP levels and cardiomyocyte contractility through NPR-B-dependent inhibition of PDE3. Cardiomyocytes were isolated from either cGES-DE5 transgenic (for cGMP measurements) or from Epac2-camps (for cAMP measurements) transgenic mice. a, b Fluorescence resonance energy transfer (FRET)-based measurements of cGMP in single cultured cardiomyocytes (n = 7 cells). The stimulation with CNP and Musclin was conducted as indicated. Representative traces (a) and a quantitative analysis (b) are shown, *p = 0.0342. c, d FRET-based measurements of cAMP in single cardiomyocytes treated as indicated (n = 13 cells). The cells were stimulated with Isoproterenol (Iso), CNP and subsequently Musclin as indicated. The graph illustrates the FRET-responses to CNP in % of the maximal Iso effect. Representative traces (c) and a quantitative analysis (d) are shown, **p = 0.0019. e–h ELISA-based measurements of cGMP and cAMP in cultured cardiomyocytes under the indicated conditions from wild-typ (WT) (e, g), **p = 0.0012 for vehicle-treated cells vs. stimulated with CNP (100 nM), ****p < 0.0001 for cells stimulated with Musclin vs. with CNP (100 nM) and Musclin, **p = 0.0013 for cells treated with CNP (100 nM) vs. cells stimulated with Musclin and CNP (100 nM) (e), *p = 0.034 (g) and global Npr2 knockout mice (f, h) (for cGMP measurement n = 4/condition and for cAMP n = 3/condition). i, j FRET-based measurements of cAMP in single WT cardiomyocytes treated as indicated. Representative traces (i) and a quantitative analysis (j) are shown (n = 6 cells without Musclin treatment and n = 8 cells with Musclin). k Representatives traces of sarcomere length and l quantification of cell shortening (from traces as shown in k) in isolated wild-type mouse cardiomyocytes treated as indicated (n = 9 cardiomyocytes per group, *p = 0.017). Cilostamide was used as PDE3 inhibitor. Data in bar graphs are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ****p < 0.0001 determined by two-tailed Student’s t test (b, d, j), one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test (e, f, l) or by Kruskal–Wallis with Dunn’s multiple comparisons test (g, h). n.s. denotes “not significant”. Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Inhibition, Isolation, Transgenic Assay, Fluorescence, Förster Resonance Energy Transfer, Cell Culture, Enzyme-linked Immunosorbent Assay, Knock-Out, Two Tailed Test

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 7 Skeletal muscle Musclin regulates cardiac cGMP and cAMP levels and phospholamban phosphorylation at the PKA phosphorylation site (Serine 16). Cardiomyocyte cGMP (a, *p = 0.0268), (c, *p = 0.048) and cAMP (b, *p = 0.029), (d, *p = 0.025) levels (determined by ELISA) after sham and TAC surgery in control (WT) and Musclin knockout (KO) mice after TAC, as well as in Sham and TAC operated mice treated either with AAV6 Control (Co) or AAV6 Musclin (Mu) (WT sham n = 5, WT TAC n = 9, KO TAC n = 10, sham AAV6 Co n = 4, sham AAV6 Mu n = 3, TAC AAV6 Co n = 6, TAC AAV6 Mu n = 7). Immunoblots for the indicated proteins (GAPDH as loading control) from cardiac protein lysate 3 days (e), cardiomyocyte protein lysate 14 days (f) or cardiac protein lysate 9 weeks (g) after TAC or sham surgery in WT or KO mice or in mice treated with AAV6 Co or AAV6 Mu as shown. The size of the proteins is indicated in kDa. Data in bar graphs are shown as mean ± standard error of the mean (SEM). *p < 0.05, determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test. Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Phospho-proteomics, Enzyme-linked Immunosorbent Assay, Control, Knock-Out, Western Blot

Journal: Nature communications

Article Title: Skeletal muscle derived Musclin protects the heart during pathological overload.

doi: 10.1038/s41467-021-27634-5

Figure Lengend Snippet: Fig. 8 Musclin inhibits the activation of cardiac fibroblasts through NPR-B dependent activation of protein kinase G (PKG). a Measurement of cardiac fibroblast proliferation by BrDU incorporation ELISA with addition of CNP and/or Musclin (n = 5/condition, **p = 0.0039 for vehicle vs. CNP, **p = 0.0019 for vehicle vs. musclin and ***p = 0.0002). b Assessment of cardiac fibroblast migration through detection of recovery of a scratch wound after 4 h during stimulation as indicated (n = 6/condition, **p = 0.0023, ***p = 0.0003 for vehicle-treated cells vs. stimulated with Musclin, and ***p = 0.0005 vs. cells stimulated with CNP and Musclin). c–e Measurement of cardiac fibroblast proliferation by BrDU incorporation ELISA under the indicated conditions (c–e) (n = 6/condition, except siNPR2 treatment n = 7); *p = 0.0103 for siControl cells, vehicle treated vs. stimulated with CNP, **p = 0.0016 vs. stimulated with Musclin and ***p = 0.0001 vs. stimulated with CNP and Musclin, *p = 0.0103 for siNPR1 cells, vehicle treated vs. stimulated with CNP, ****p < 0.0001 vs. stimulated with Musclin and vs. stimulated with CNP and Musclin (c); *p = 0.0243, **p = 0.0055 and ***p = 0.0003 (d); **p = 0.0021 for siControl cells, vehicle treated vs. stimulated with CNP, ***p = 0.0002 vs. stimulated with Musclin, and ****p < 0.0001 vs. treated with both CNP and Musclin, ***p = 0.0002 for siNPR3 cells, vehicle treated vs. stimulated with CNP, ****p < 0.0001 vs. treated with Musclin and vs. cells treated with both CNP and Musclin (e). Assessment of cardiac fibroblast migration by scratch assay in cardiac fibroblasts (n = 6/condition) treated with siRNA, CNP and Musclin as indicated (f–h), *p = 0.036 for siControl cells, vehicle treated vs. treated with CNP, ***p < 0.0001 vs. Musclin and vs. stimulated with CNP and Musclin, *p = 0.046 for siNPR1 cells, vehicle treated vs. stimulated with CNP, **p = 0.0013 vs. Musclin and ****p < 0.0001 vs. cells treated with both CNP and Musclin (f); *p = 0.0148 for siControl cells, vehicle treated vs. treated with CNP, **p = 0.0013, and *p = 0.0148 between siControl and siNPR2 cells treated with both CNP and Musclin (g); *p = 0.0162 for siControl cells, vehicle treated vs. cells stimulated with CNP, **p = 0.0042 vs. cells treated with Musclin and ***p = 0.0004 vs. cells stimulated with both CNP and Musclin, *p = 0.0162 for siNPR3 cells, vehicle treated vs. stimulated with CNP or Musclin and ***p = 0.0002 vs. stimulated with Musclin and CNP, ***p = 0.0005 for siControl cells treated with Musclin und CNP vs. siNPR3 cells stimulated with Musclin and CNP, ***p = 0.0008 for vehicle-treated siControl cells vs. vehicle-treated siNPR3 cells (h). i, j Assessment of cardiac fibroblast proliferation and migration after stimulation with Musclin, CNP or the PKG inhibitor DT3 as indicated (for proliferation n = 7/condition, **p = 0.0018 for vehicle vs. Musclin treated cells and *p = 0.016 for cells stimulated with Musclin vs. cells treated with Musclin and DT3 (i), and for migration n = 4/condition, **p = 0.0043 for vehicle-treated cells vs. stimulated with Musclin, ***p = 0.0005 for cells treated with Musclin vs. treated with DT3 (j)). k Immunoblot from cardiac fibroblasts’ protein lysate for the indicated proteins after stimulation as indicated. GAPDH was used as loading control. The size of the proteins is indicated in kDa. Data in bar graphs are shown as mean ± standard error of the mean (SEM). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 determined by one-way ANOVA followed by the Holms–Sidak’s multiple comparisons test. Mu stands for Musclin. Source data are provided as a source data file.

Article Snippet: The cells were stimulated with recombinant C-type natriuretic peptide (CNP, #N8768, Sigma Aldrich) with or without the addition of Musclin (#RD172079100, BioVendor) for 1 h. The CNP levels were determined in the supernatants using the CNP ELISA kit (#MBS2514795, detecting mature CNP peptides, MyBioSource) according to the manufacturer’s protocol.

Techniques: Activation Assay, BrdU Incorporation Assay, Enzyme-linked Immunosorbent Assay, Migration, Wound Healing Assay, Western Blot, Control