Hiromu Takematsu

The mechanisms leading to the formation of sclerotic lesions in focal segmental glomerulosclerosis (FSGS) remain incompletely understood; however, podocyte detachment and loss are considered key pathogenic events. Ubiquitin-specific protease 40 (USP40) is a deubiquitylating enzyme expressed in podocytes. In the present study, we investigated the role of USP40 in podocytes, focusing on its impact on the adhesion molecule integrin β1, which is essential for anchoring podocytes to the glomerular basement membrane. When USP40 knockout mice were subjected to an experimental FSGS model, they exhibited significantly more severe proteinuria and glomerulosclerosis than control mice, along with a marked reduction in podocyte number and integrin β1 expression. Consistently, knockdown of USP40 in cultured podocytes resulted in decreased integrin β1 expression and impaired adhesive properties compared with sham-treated cells. In HEK293 cells transfected with ubiquitin constructs, USP40 suppressed integrin β1 monoubiquitylation. In a separate internalization assay, USP40 prevented the clathrin-mediated endocytosis of integrin β1. In USP40 knockout mice, clathrin-coated vesicles colocalizing with integrin β1 were more frequently observed in podocyte foot processes than in control mice. Together, these findings suggest that USP40 functions as a deubiquitylating enzyme that stabilizes integrin β1 at the podocyte plasma membrane by preventing its endocytosis. We therefore propose that the USP40-integrin β1 axis represents a potential therapeutic target for FSGS.

CD22 is an inhibitory receptor expressed in B cells and is constitutively associated with α2,6-sialylated membrane proteins expressed on the same cell ( cis -ligands). However, interaction with cis -ligands is required for the function of CD22 only in part. To address the role of ligand interaction of CD22 in immune responses, here we generated anti-CD22 antibody 1C5 that specifically inhibits ligand binding of CD22. Both Cd22 ^−/− mice and mice treated with 1C5 show expansion of regulatory B (Breg) cells in follicular (FO) B cells, suggesting a crucial role of ligand interaction of CD22 in inhibiting the expansion of FO Breg cells. CD22 appears to recognize BCR and TLRs thereby directly or indirectly suppressing TLR signaling essential for expansion of Breg cells. Treatment of mice with 1C5 ameliorates skin graft rejection and type 1 diabetes with expansion of regulatory γδ T cells probably through expansion of Breg cells, suggesting ligand interaction of CD22 as a novel target of therapy for autoimmune diseases and graft rejection.

Abstract Coley’s Toxin comprised a mixture of cell-free, heat-treated culture media from Streptococcus pyogenes (originally Streptococus erysipelatos) and Serratia marcescens (originally Bacillus prodigiosus). A 250 kDa tumor hemorrhage-inducing polysaccharide “PS1” is reported here secreted into culture medium by S. marcescens. Four h after PS1 is injected at 32 μg/kg (10pM) into the tail vein of Balb/C mice bearing C26 subcutaneous colon-derived tumors, tumor-specific capillary hemorrhage is exhibited in 90% of tumors. As a positive control, CM101, a similar tumor hemorrhagic polysaccharide from Streptococcus agalactica caused tumor hemorrhage in 75% of tumors in the Balb/C-C26 model at 7.5 μg/kg(2.5pM). CM101 has previously been safety tested in a Phase I clinical trial. These two polysaccharides have merit to be identified as the active principal ingredients (API’s) of Coley’sToxin. Additional approaches to cancer therapy are a global need. No matter the level of wealth of victims, some cancers are still incurable. Recall in recent years the tragic early cancer deaths of Steve Jobs and Paul Allen among other luminaries. Streptococcal and Serratia bacterial extracts have unique tumor specific capillary destructive activity, with observations originating with sarcomas cured by nosocomial  erysipelas  infections in the 1860’s. The active pharmaceutical ingredients (API’s) in these extracts and Coley’s Toxins are proposed to be polysaccharides.