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Chatterjee, T.

Publications and source records attributed to Chatterjee, T..

2 recordsLinked to original sources

Redox Nanomedicine Cures Chronic Kidney Disease (CKD) by Mitochondrial Reconditioning

Targeting reactive oxygen species (ROS) while maintaining cellular redox signaling is crucial in the development of redox medicine for the therapeutic benefit as the origin of several prevailing diseases including chronic kidney disease (CKD) is linked to ROS imbalance and associated mitochondrial dysfunction. Here, we have shown that an indigenously developed nanomedicine comprising of Mn3O4 nanoparticles duly functionalized by biocompatible ligand citrate (C-Mn3O4 NPs) can maintain cellular redox balance in an animal model. We developed a cisplatin-induced CKD model in C57BL/6j mice where severe mitochondrial dysfunction resulting in oxidative distress lead to the pathogenesis. Four weeks of treatment with C-Mn3O4 NPs restored renal function, preserved normal kidney architecture, ameliorated overexpression of pro-inflammatory cytokines, and arrested glomerulosclerosis and interstitial fibrosis in CKD mice. A detailed study involving human embryonic kidney (HEK 293) cells and isolated mitochondria from experimental animals revealed that the molecular mechanism behind the pharmacological action of the nanomedicine involves protection of structural and functional integrity of mitochondria from oxidative damage, the subsequent reduction in intracellular ROS, and maintenance of cellular redox homeostasis. To the best of our knowledge, such studies that efficiently treated a multifaceted disease like CKD using a biocompatible redox nanomedicine are sparse in the literature. Successful clinical translation of this nanomedicine may open a new avenue in redox-mediated therapeutics of several other diseases (e.g., diabetic nephropathy, neurodegeneration, and cardiovascular disease) where oxidative distress plays a central role in pathogenesis.

pharmacology and toxicology

Anti-GPR56 monoclonal antibody potentiates GPR56-mediated Src-Fak signaling to modulate cell adhesion

GPR56, also known as ADGRG1, is a member of the adhesion G protein-coupled receptor (aGPCR) family shown to play important roles in cell adhesion, brain development, immune system function, and tumorigenesis. GPR56 is upregulated in colorectal cancer and high expression correlates with poor prognosis. Several studies have shown that GPR56 couples to the G12/13 class of heterotrimeric G-proteins to promote RhoA activation. However, due to its structural complexity and lack of a high affinity receptor-specific ligand, the complete GPR56 signaling mechanism still remains largely unknown. To delineate the activation mechanism and intracellular signaling functions of GPR56, we generated a monoclonal antibody (mAb) which binds GPR56 with high affinity and specificity to the extracellular domain (ECD). We show that overexpression of GPR56 in 293T cells lead to increased phosphorylation of Src, Fak, and paxillin adhesion proteins and activation of the G12/13-RhoA-mediated serum response factor (SRF) pathway. Treatment of cells with anti-GPR56 mAb potentiated Src-Fak phosphorylation, RhoA-SRF signaling, and cell adhesion. Consistently, knockdown of GPR56 in colorectal cancer cells decreased Src-Fak pathway phosphorylation and cell adhesion. Interestingly, GPR56-mediated activation of Src-Fak phosphorylation occurred independent of RhoA, yet mAb-induced potentiation of RhoA-SRF signaling was Src-dependent. Furthermore, we show that the Serine-Threonine-Proline-rich (STP) region of the ECD of GPR56 was not essential for mAb binding, yet was required for activation of Src-Fak signaling. These data support a new ECD-dependent mechanism by which GPR56 functions to regulate cell adhesion through activation of Src-Fak signaling.

molecular biology