Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: Recombinant cMET-dIgA displays potent antagonist activity and retains the ability to transcytose via pIgR (A) cMET-dIgA specifically bound mouse (top row), human (2 nd row), and rat (3rd row) cMET in transiently transfected CHO cells. An empty DNA vector (bottom row) was used for control. Human dIgA (used as a primary detection antibody, green); cMET (commercial IgG specific for all 3 species, red); DAPI (blue). Scale bar, 20μM. (B) cMET-dIgA blocked endogenous cMET receptor activation in mouse IMCD-3 cells after HGF stimulation (left panels) and did not cause receptor dimerization in the absence of HGF (right panels). Capmatinib (cMET SM inhibitor) was used as a negative control. Cells were lysed in SDS and analyzed via immunoblot. Quantification of immunoblot signal intensity from +HGF/+dIgA samples was performed using Image Studio Lite, normalized to actin. See also . (C) Transcytosis of cMET-dIgA visualized via immunoblot of human IgA in apical or basolateral (BL) media samples from MDCK cells (with/without pIgR stably transfected). All samples were run under nonreducing conditions. A vertical line between lanes indicates that the two sections of the blot were adjusted separately on Photoshop to improve visibility. (D) Transcytosis into apical compartments also occurred under low-calcium conditions in MDCK cells expressing pIgR. GP-135 (apical membrane marker, red); human dIgA (used as a primary detection antibody, green); DAPI (blue). Scale bar, 10 μM.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Recombinant, Activity Assay, Transfection, Plasmid Preparation, Control, Activation Assay, Negative Control, Western Blot, Stable Transfection, Expressing, Membrane, Marker

Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: cMET-dIgA traffics to PKD Han rat cysts and downregulates cMET signaling in cyst-lining cells (A and B) Untreated PKD Han:SPRD adult male rats upregulate pIgR expression compared to WT as seen in (A) immunoblot of whole kidney lysates, n = 3, as well as (B) paraffin-embedded kidney sections stained by immunofluorescence for pIgR (green), AQP1 (red), and DAPI (blue). Rats were injected with a single dose of 1 mg cMET-dIgA and sacrificed 24 h later, n = 5. (C) Immunoprecipitation of CF using nitrilotriacetic acid (NTA)-nickel (Ni) ion resin followed by immunoblot specific for human IgA1 revealed secretory IgA (sIgA) recovery. Un-injected purified dimeric IgA (dIgA) was loaded for size comparison. A vertical line between lanes indicates that the two sections of the blot were adjusted separately on Photoshop to improve visibility. (D) Immunofluorescent staining of C-terminal cMET (red), AQP1 (red), and DAPI (blue), as well as immunohistochemistry staining of phospho-cMET, decreased after dIgA administration. (E) Immunofluorescent staining of Ki67 (cyan) and DAPI (red) showed the most significant decrease in cyst-lining cells (white arrowheads), with quantification of the fraction of Ki67+ nuclei in a cyst. Each point on the graph represents that percentage for a single cyst in a given field. All image scale bars, 100 μm. Statistical analyses were performed using Mann-Whitney unpaired one-tailed t test and represented as mean ± SEM. A p value of less than 0.05 was considered significant.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Expressing, Western Blot, Staining, Immunofluorescence, Injection, Immunoprecipitation, Purification, Comparison, Immunohistochemistry, MANN-WHITNEY, One-tailed Test

Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: cMET-dIgA accumulates and stabilizes in Bpk mouse cyst lumen via pIgR-mediated transport (A) Untreated Bpk mice, P14, upregulate pIgR expression in whole kidney lysates compared to age-matched WT mice. (B) Serum (S), CF-depleted kidneys (DKs), and cyst fluid (CF) from Juvenile Bpk mice were analyzed 1, 3, 5, and 8 days post-dIgA injection. Sample concentrations were equalized via spectrophotometry. See also . (C) Recovery of dIgA in serum and CF was quantified 1 and 3 days post-injection via sandwich ELISA. Triplicate values from each +dIgA timepoint group (n = 2) was plotted from CF or serum and represented as mean ± SEM. (D) Side-by-side comparison of these samples on a nonreducing SDS-PAGE gel. (E) Immunoprecipitation of CF using NTA-Ni resin and antibodies specific for either human IgA1 (nonreduced) or secretory component (SC) (reduced). Un-injected cMET-dIgA was loaded on all immunoblots for size comparison of dimeric (d) and secretory (s) IgA. A vertical line between lanes indicates that the two sections of the blot were adjusted separately on Photoshop to improve visibility. (F) Immunofluorescent staining of human IgA (green) and DAPI (blue) shows targeting of cMET-dIgA to renal cyst lumen. Scale bar, 100 μm.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Expressing, Injection, Spectrophotometry, Sandwich ELISA, Comparison, SDS Page, Immunoprecipitation, Western Blot, Staining

Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: cMET-dIgA treatment causes potent target pathway inhibition in rapid-onset Bpk mouse model (A) Short-term treatment timeline in Bpk model that begins cystogenesis in utero (ED). WT and Bpk mice were injected with 20 mg/kg/day cMET-dIgA or vehicle for 1 week starting at post-natal day (P)7. Analysis of kidney sections from these mice included (B) immunofluorescent staining for total cMET (red), proximal tubules stained with LTL ( Lotus tetragonolobus lectin) marker (green), and DAPI (blue); (C) quantification of total cMET from (B) in cyst-lining cells; (D) immunohistochemistry stain of phospho-cMET; (E) immunofluorescent staining for phospho-ERK1/2 (red), human IgA (green), and DAPI (blue); (F) quantification of phospho-ERK from (E) in cyst-lining cells; and (G) immunohistochemistry stain of phospho-AMPK. Nuclei were counterstained with hematoxylin. All image scale bars, 50 μm. Statistical analyses were performed using Mann-Whitney unpaired one-tailed t test and represented as mean ± SEM. A p value of less than 0.05 was considered significant.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Inhibition, In Utero, Injection, Staining, Marker, Immunohistochemistry, MANN-WHITNEY, One-tailed Test

Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: cMET-dIgA treatment slows disease progression in rapid-onset Bpk mouse model H&E stain of Bpk kidney sections after 1 week of daily i.p cMET-dIgA or vehicle injections. (A–F) (A) Representative images, scale bar = 100 μm, and (B) stitched composite images, scale bar, 1 mm. Quantification of (C) cystic index by Photoshop grid scoring, (D) cortical cyst area as a fraction of the total tissue area using ImageJ, (E) two-kidney-to-body weights (2K/BW) of mice from each group after treatment, and (F) creatinine concentrations in BPK serum samples using QuantiChrom creatinine assay kit. (G–J) (G) Immunofluorescent staining for the proliferation marker, Ki67 (cyan) and DAPI (red); scale bar, 50 μm; (H) TUNEL stain for apoptotic cells (cyan) and DAPI (red); scale bar, 100 μm, with quantification of the fraction of Ki67+ or TUNEL+ nuclei in a Bpk cyst or in WT tubular epithelial cells. Each point on the graph represents that percentage for a single cyst or tubule in a given field. dIgA treatment had no significant effect on (I) body weight or (J) lung weight as a fraction of total body weight compared to vehicle treatment in WT or Bpk mice. Statistical analyses were performed using Mann-Whitney unpaired one-tailed t test and represented as mean ± SEM. A p value of less than 0.05 was considered significant.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Biomarker Discovery, Staining, Marker, TUNEL Assay, MANN-WHITNEY, One-tailed Test

Journal: Cell Reports Medicine

Article Title: Development of a cyst-targeted therapy for polycystic kidney disease using an antagonistic dimeric IgA monoclonal antibody against cMET

doi: 10.1016/j.xcrm.2025.102335

Figure Lengend Snippet: cMET-dIgA treatment prevents cyst expansion in an orthologous Pkd1 mouse model (A–G) (A) Treatment timeline in tamoxifen-inducible Pkd1 fl/fl mouse model. PKD1 gene excision was induced on p10 followed by single i.p. injections of either 10 mg/kg/2 day cMET-dIgA or vehicle starting at 3 weeks post-induction (p31) for 2 weeks and sacrificed 2 days after the final injection (p45). Analysis of paraffin-embedded kidney sections from these mice ( n = 4) included immunofluorescent staining for (B) cMET or TUNEL (cyan) and DAPI (red), scale bar, 100um; quantification using ImageJ of (C) total cMET fluorescent intensity in cyst cells, median denoted in each group; and (D) TUNEL + cyst cells as a fraction of total nuclei in the cyst; (E) H&E stain-representative images; scale bar, 100 μm; stitched composite images, scale bar, 1 mm. (F) Two kidney weight as a fraction of total body weight (p45). (G) Quantification of individual cyst areas using ImageJ. Each point represents one cyst; median denoted in each group. (H–J) (H) Sirius Red Fast Green collagen (red) staining, scale bar, 100 μm; quantification (data not shown) was performed using Adobe Photoshop/grid scoring. Analysis of (I) serum creatinine and (J) blood urea nitrogen (BUN) in serum of WT and PKD (−/+dIgA) mice. (K) Concentrations of cMET-dIgA recovered on p45 in CF, serum, kidney lysate, and lung lysate via sandwich ELISA specific for human IgA1. See also and . Statistical analyses were performed using Mann-Whitney unpaired one-tailed t test and represented as mean ± SD. A p value of less than 0.05 was considered significant.

Article Snippet: cMET c-terminal , ProSci , Cat#79-590; RRID: AB_2332792.

Techniques: Injection, Staining, TUNEL Assay, Sandwich ELISA, MANN-WHITNEY, One-tailed Test