Journal: Bioactive Materials

Article Title: Bone targeted microenvironment actuated engineered exosomes for precision therapy of IBD associated bone loss

doi: 10.1016/j.bioactmat.2026.04.034

Figure Lengend Snippet: Schematic illustration of the design, bone targeting, and therapeutic mechanism of ExoBIP in IBD-associated bone loss . BMSC-derived exosomes were engineered to generate ExoBIP for bone-targeted, inflammation-triggered IL-18 neutralization: IL-18BP was first coupled to the SDSSD bone-homing peptide, and the resulting IL-18BP-SDSSD conjugate was then grafted onto the exosome surface via an MMP9-responsive cleavable linker, enabling selective IL-18BP release within the inflammatory skeletal microenvironment while preserving IL-18's gut physiology. Following systemic administration, ExoBIP preferentially accumulates in bone tissue, where elevated matrix metalloproteinases (MMPs) in the inflammatory microenvironment cleave the linker to release IL-18BP. Neutralization of IL-18 suppresses T cell activation and IFN-γ–mediated inhibition of osteogenic activity, reduces RANKL-mediated osteoclastogenesis, and restores the balance between osteoclast and osteoblast activity, thereby alleviating IBD-induced bone loss.

Article Snippet: Cells were activated with plate-bound anti-CD3ε (1 μg/mL) and soluble anti-CD28 (1 μg/mL) in the presence of 0.5 ng/mL IL-2 for 24 h. Groups included a PBS control; 20 ng/mL recombinant IL-18 (RP02521, ABclonal); 20 ng/mL recombinant IL-18BP (50206-M08H, Sino Biological); 10 μM LY294002, a PI3K pathway inhibitor (S1737, Beyotime); 25 ng/mL IFN-γ (P6137, Beyotime); 25 ng/mL RANKL; 1 μg/mL IFN-γ Antagonist (HY-P4717, MCE); and 1 μg/mL Anti-Mouse RANKL Antibody (HY-P990165, MCE); 1 μM Ruxolitinib (HY-50856, MCE), a JAK1/2 pathway inhibitor; 5 μM BAY 11-7821 (HY-13453, MCE), an NF-κB pathway inhibitor.

Techniques: Derivative Assay, Neutralization, Preserving, Activation Assay, Inhibition, Activity Assay

Journal: Bioactive Materials

Article Title: Bone targeted microenvironment actuated engineered exosomes for precision therapy of IBD associated bone loss

doi: 10.1016/j.bioactmat.2026.04.034

Figure Lengend Snippet: Persistent IL-18 accumulation after intestinal recovery drives bone loss through T cell-mediated remodeling imbalance (see also Supporting ) (A) Schematic illustration of the DSS-induced colitis model, sulfasalazine (SASP) treatment. (B) Il1 8 mRNA expression in colonic tissue measured by qPCR. (C) Representative immunofluorescence staining of IL-18 in colonic sections from Healthy, UC, and UC + Treatment mice at day 28 and day 56. (D) Serum IL-18 levels measured by ELISA at indicated time points. (E) Il1 8 mRNA expression in femoral bone tissue determined by qPCR. (F) Representative immunofluorescence staining of IL-18 in femoral bone marrow. (G) Schematic illustration of IL-18-mediated bone loss in DSS-induced UC and the effect of IL-18BP. (H) Representative micro-CT images of trabecular bone from Healthy, UC, and IL-18BP-treated mice. (I) Quantitative micro-CT analysis of bone parameters, including BMD, BV/TV. (J) Representative immunofluorescence staining of OPN and OSX in femoral bone sections. (K) Quantification of OPN-positive and OSX-positive areas in bone tissue. (L) Representative TRAP staining of femoral bone sections. (M) Quantification of osteoclast number (N.Oc/B.Pm). (N) Representative images of double fluorochrome labeling (calcein and alizarin red) in femoral bone. (O) Quantification of dynamic bone formation parameters, including mineral apposition rate (MAR). (P) Schematic illustration of the CD8 + T cell-conditioned medium system used to assess indirect effects of IL-18 on osteogenic and osteoclastogenic differentiation. (Q) Representative ALP and ARS staining of BMSCs cultured under indicated treatments. (R) Representative TRAP staining of osteoclasts differentiated under indicated conditions. (S) Quantification of ALP-positive area, ARS-positive area, and TRAP-positive area. (T) Western blot analysis of PI3K-Akt signaling in CD8 + T cells treated with IL-18 and/or IL-18BP, with corresponding densitometric analysis. For (C-D, I-O, S), data are presented as mean ± s.d. One-way ANOVA followed by Tukey's multiple-comparisons test was used for multiple groups. p < 0.05 was considered statistically significant. Six mice per group. For qPCR, ΔCt values were analyzed (equivalent to log2-transformed fold changes), fold changes (2^−ΔΔCt) are shown for visualization. p < 0.05 was considered statistically significant. n = 3 biological replicates per group.

Article Snippet: Cells were activated with plate-bound anti-CD3ε (1 μg/mL) and soluble anti-CD28 (1 μg/mL) in the presence of 0.5 ng/mL IL-2 for 24 h. Groups included a PBS control; 20 ng/mL recombinant IL-18 (RP02521, ABclonal); 20 ng/mL recombinant IL-18BP (50206-M08H, Sino Biological); 10 μM LY294002, a PI3K pathway inhibitor (S1737, Beyotime); 25 ng/mL IFN-γ (P6137, Beyotime); 25 ng/mL RANKL; 1 μg/mL IFN-γ Antagonist (HY-P4717, MCE); and 1 μg/mL Anti-Mouse RANKL Antibody (HY-P990165, MCE); 1 μM Ruxolitinib (HY-50856, MCE), a JAK1/2 pathway inhibitor; 5 μM BAY 11-7821 (HY-13453, MCE), an NF-κB pathway inhibitor.

Techniques: Expressing, Immunofluorescence, Staining, Enzyme-linked Immunosorbent Assay, Micro-CT, Labeling, Cell Culture, Western Blot, Transformation Assay

Journal: Bioactive Materials

Article Title: Bone targeted microenvironment actuated engineered exosomes for precision therapy of IBD associated bone loss

doi: 10.1016/j.bioactmat.2026.04.034

Figure Lengend Snippet: Engineering and Characterization of an MMP-Responsive Bone-Targeted Exosome (ExoBIP) (see also Supporting ) (A) Schematic of ExoBIP construction and mechanism of action. IL-18BP was dual-functionalized with an MMP-cleavable linker (PLGVR) and a bone-targeting peptide (SDSSD) via NHS–amine chemistry. Separately, BMSC-derived exosomes (Exo) were treated with TCEP to expose surface thiol groups (-SH). The maleimide-terminated IL-18BP complex was then conjugated to the thiol-activated exosomes via thiol–maleimide coupling to form ExoBIP. Upon reaching MMP-rich bone resorption sites, the linker is cleaved, releasing IL-18BP to neutralize IL-18, while BMSC-derived exosomes preserve their inherent osteogenic potential. Some elements of this figure were created with BioRender.com (license number: YG28QKC6SI). (B) Representative TEM image of ExoBIP stained with uranyl acetate (left) and TEM image of ExoBIP bound to secondary antibody-linked gold nanoparticles (right). (C) Nanoparticle tracking analysis (NTA) and zeta potential characterization. (D) Western blot analysis of exosomal markers (CD9, CD63, CD81, TSG101) and IL-18BP conjugation. (E) Representative super-resolution confocal microscopy images of ExoBIP, with IL-18BP (red) and Exo membrane (green). (F) Line-scan analysis of Exo and IL-18BP fluorescence intensity. Signal profiles across individual particles confirmed spatial overlap and surface colocalization. (G) Protease-responsive release kinetics of IL-18BP from ExoBIP. ELISA demonstrated that recombinant MMP9 triggered sustained IL-18BP release from ExoBIP, which was abrogated by MMP inhibitor GM6001. (H) ELISA-based binding analysis showing that activity of IL-18BP released from ExoBIP is similar to the original IL-18BP. (I) Colloidal stability of ExoBIP. ExoBIP maintained stable particle size and surface charge over 7 days at 4 °C (J) Lyophilization and reconstitution of ExoBIP. Lyophilized ExoBIP powder reconstituted in PBS exhibited a distinct Tyndall effect. (K) Post-rehydration characterization of ExoBIP. Particle size and zeta potential remained stable after lyophilization, supporting storage and application feasibility. For (C, G-H, I), data are presented as mean ± s.d. Two-tailed unpaired Student's t-test was used for comparisons between two groups, and one-way ANOVA followed by Tukey's multiple-comparisons test was used for multiple groups. p < 0.05 was considered statistically significant. For C, zeta potential was measured five times; for G and H, ELISA assays were performed in triplicate; and for I, measurements were repeated three times.

Article Snippet: Cells were activated with plate-bound anti-CD3ε (1 μg/mL) and soluble anti-CD28 (1 μg/mL) in the presence of 0.5 ng/mL IL-2 for 24 h. Groups included a PBS control; 20 ng/mL recombinant IL-18 (RP02521, ABclonal); 20 ng/mL recombinant IL-18BP (50206-M08H, Sino Biological); 10 μM LY294002, a PI3K pathway inhibitor (S1737, Beyotime); 25 ng/mL IFN-γ (P6137, Beyotime); 25 ng/mL RANKL; 1 μg/mL IFN-γ Antagonist (HY-P4717, MCE); and 1 μg/mL Anti-Mouse RANKL Antibody (HY-P990165, MCE); 1 μM Ruxolitinib (HY-50856, MCE), a JAK1/2 pathway inhibitor; 5 μM BAY 11-7821 (HY-13453, MCE), an NF-κB pathway inhibitor.

Techniques: Derivative Assay, Staining, Zeta Potential Analyzer, Western Blot, Conjugation Assay, Confocal Microscopy, Membrane, Fluorescence, Enzyme-linked Immunosorbent Assay, Recombinant, Binding Assay, Activity Assay, Lyophilization, Two Tailed Test

Journal: Bioactive Materials

Article Title: Bone targeted microenvironment actuated engineered exosomes for precision therapy of IBD associated bone loss

doi: 10.1016/j.bioactmat.2026.04.034

Figure Lengend Snippet: Bone-Targeting Efficiency and In Vivo Distribution of ExoBIP (see also Supporting ) (A) Representative ex vivo fluorescence images of osteoporotic femurs incubated with Cy5-labeled exosomes for 12 h (B) Quantification of Cy5-positive area showing significantly enhanced bone-binding affinity of ExoBIP over other formulations. (C) Representative in vivo IVIS images of whole-body biodistribution over 96 h following intravenous injection, and ex vivo of major organs and bones. (D) Time course radiance quantification confirming prolonged bone retention of ExoBIP compared with controls. (E) Ex vivo fluorescence imaging quantification of major organs and bones at 24 h post-injection. (F) Representative immunofluorescence images of femoral sections labeled with Cy3. (G) Quantification of Cy3-positive area in bone tissue. (H) Immunofluorescence staining of femoral sections for IL-18BP. (I) Quantification of IL-18BP-positive area in bone tissue. For (B, E, G, I), data are presented as mean ± s.d. Two-tailed unpaired Student's t-test was used for comparisons between two groups, and one-way ANOVA followed by Tukey's multiple-comparisons test was used for multiple groups. p < 0.05 was considered statistically significant. Six mice per group were used for in vitro bone-targeting experiments in (B) and bone tissue immunofluorescence in (G-H), whereas three mice per group were used for in vivo fluorescence imaging in (D-F).

Article Snippet: Cells were activated with plate-bound anti-CD3ε (1 μg/mL) and soluble anti-CD28 (1 μg/mL) in the presence of 0.5 ng/mL IL-2 for 24 h. Groups included a PBS control; 20 ng/mL recombinant IL-18 (RP02521, ABclonal); 20 ng/mL recombinant IL-18BP (50206-M08H, Sino Biological); 10 μM LY294002, a PI3K pathway inhibitor (S1737, Beyotime); 25 ng/mL IFN-γ (P6137, Beyotime); 25 ng/mL RANKL; 1 μg/mL IFN-γ Antagonist (HY-P4717, MCE); and 1 μg/mL Anti-Mouse RANKL Antibody (HY-P990165, MCE); 1 μM Ruxolitinib (HY-50856, MCE), a JAK1/2 pathway inhibitor; 5 μM BAY 11-7821 (HY-13453, MCE), an NF-κB pathway inhibitor.

Techniques: In Vivo, Ex Vivo, Fluorescence, Incubation, Labeling, Binding Assay, Injection, Imaging, Immunofluorescence, Staining, Two Tailed Test, In Vitro

Journal: Advanced Science

Article Title: A Dual‐Membrane Biomimetic Nanoplatform Enables Triple‐Modal Therapy Against SARS‐CoV‐2 Through Viral Decoy, Inflammation Neutralizing, and Intracellular RNAi

doi: 10.1002/advs.77581

Figure Lengend Snippet: Schematic design and proposed therapeutic mechanism of the dual‐membrane biomimetic nanoplatform [A&T]MLN. (A) Fabrication process of [A&T]MLN. Cell membranes isolated from ACE2‐overexpressing HEK293T cells and THP‐1‐derived macrophages are fused and subsequently coated onto siRNA‐loaded lipid nanoparticles (prepared by thin‐film hydration) to generate the final nanoconstruct. (B) Proposed triple‐modal therapeutic action against SARS‐CoV‐2 infection: (i) neutralization of free virions via high‐affinity binding of surface‐displayed ACE2; (ii) attenuation of the cytokine storm through scavenging of key inflammatory mediators (e.g., IL‐6, TNF‐α) by macrophage‐derived membrane receptors; and (iii) intracellular delivery of therapeutic siRNA to suppress viral replication.

Article Snippet: Male K18‐hACE2‐2A‐CreERT2 mice (6–8 weeks old; Saiye Model Biological Research Center Co., Ltd., China) were anesthetized and administered 50 μL of SARS‐CoV‐2 S1SP (RayBiotech, USA) via intratracheal instillation at a dose of 400 mg/kg, followed by an air bolus (150 μL) to promote distribution.

Techniques: Membrane, Isolation, Derivative Assay, Infection, Neutralization, Binding Assay

Journal: Advanced Science

Article Title: A Dual‐Membrane Biomimetic Nanoplatform Enables Triple‐Modal Therapy Against SARS‐CoV‐2 Through Viral Decoy, Inflammation Neutralizing, and Intracellular RNAi

doi: 10.1002/advs.77581

Figure Lengend Snippet: Molecular basis for viral interaction and cytokine neutralization. (A) Protein composition. Coomassie blue‐stained SDS‐PAGE gel of proteins extracted from [A&T]MLN and [A&T]M; LN serves as a negative control. (B) Presence of key functional proteins. Western blot analysis confirming the transfer of ACE2, IL‐6R, TNF‐R1, IL‐1R, CD116, and CD47 to [A&T]MLN and [A&T]M; LN serves as a negative control. (C) Protein secondary structure integrity. Far‐UV circular dichroism (CD) spectra of proteins extracted from [A&T]MLN, THP‐1 membrane, [A&T]M, AMLN, and TMLN. (D) Binding kinetics to SARS‐CoV‐2 spike protein. Biolayer interferometry (BLI) sensorgrams of serially diluted [A&T]MLN (62.5–1000 n m ) binding to immobilized spike S1+S2 ECD. Red lines represent the global fit to a 1:1 binding model ( R 2 = 0.99). (E, F) Virus‐induced changes in nanoparticle properties. Hydrodynamic diameter (E) and zeta potential (F) of [A&T]MLN after 2 h incubation with authentic wild‐type (WT) or Omicron BA.5 SARS‐CoV‐2. Data are presented as mean ± SD ( n = 3). Statistical significance was determined by one‐way ANOVA. ns, not significant; ** P < 0.01; *** P < 0.001; **** P < 0.0001. (G, H) Visualization of virus‐nanoparticle complexes. Representative TEM images of [A&T]MLN bound to authentic SARS‐CoV‐2 WT (G) or Omicron BA.5 (H). Scale bars, 100 nm. (I) In vitro cytokine neutralization. Residual levels of human recombinant IL‐6, IL‐1β, TNF‐α, and GM‐CSF after incubation with AMLN, TMLN, or [A&T]MLN (0–10 µg/mL), quantified by ELISA. Data are presented as mean ± SD ( n = 3). Statistical significance was determined by one‐way ANOVA. ns, not significant; * P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001.

Article Snippet: Male K18‐hACE2‐2A‐CreERT2 mice (6–8 weeks old; Saiye Model Biological Research Center Co., Ltd., China) were anesthetized and administered 50 μL of SARS‐CoV‐2 S1SP (RayBiotech, USA) via intratracheal instillation at a dose of 400 mg/kg, followed by an air bolus (150 μL) to promote distribution.

Techniques: Neutralization, Staining, SDS Page, Negative Control, Functional Assay, Western Blot, Circular Dichroism, Membrane, Binding Assay, Virus, Zeta Potential Analyzer, Incubation, In Vitro, Recombinant, Enzyme-linked Immunosorbent Assay

Journal: Advanced Science

Article Title: A Dual‐Membrane Biomimetic Nanoplatform Enables Triple‐Modal Therapy Against SARS‐CoV‐2 Through Viral Decoy, Inflammation Neutralizing, and Intracellular RNAi

doi: 10.1002/advs.77581

Figure Lengend Snippet: Broad‐spectrum antiviral activity of [A&T]MLN against SARS‐CoV‐2. (A) Dose‐response neutralization of pseudotyped SARS‐CoV‐2 variants. Neutralization activity of [A&T]MLN against a panel of pseudoviruses (WT, Alpha, Beta, Gamma, Delta, Omicron BA.4/5) was measured by a luciferase‐reporter assay. Data are presented as mean ± SD ( n = 3). (B) Contribution of the ACE2 membrane to neutralization potency. Neutralization of WT and Omicron BA.4/5 pseudoviruses by [A&T]MLN was compared to that of nanoparticles lacking the ACE2 membrane. Data are presented as mean ± SD ( n = 3). Statistical significance was determined by one‐way ANOVA. ns, not significant; * P < 0.05; **** P < 0.0001. (C) Schematic illustration of the authentic virus neutralization assay. (D) Neutralization of authentic SARS‐CoV‐2 variants. Vero E6 cells pretreated with [A&T]MLN (19.5–78 µg/mL) were infected with WT, Beta, or Omicron BA.5 viruses (MOI = 0.01). Viral titers were determined by TCID 50 . Data are presented as mean ± SD ( n = 3).

Article Snippet: Male K18‐hACE2‐2A‐CreERT2 mice (6–8 weeks old; Saiye Model Biological Research Center Co., Ltd., China) were anesthetized and administered 50 μL of SARS‐CoV‐2 S1SP (RayBiotech, USA) via intratracheal instillation at a dose of 400 mg/kg, followed by an air bolus (150 μL) to promote distribution.

Techniques: Activity Assay, Neutralization, Luciferase, Reporter Assay, Membrane, Virus, Infection