Sriram Ambadapadi

Immune cell invasion after the transplantation of solid organs is directed by chemokines binding to glycosaminoglycans (GAGs), creating gradients that guide immune cell infiltration. Renal transplant is the preferred treatment for end stage renal failure, but organ supply is limited and allografts are often injured during transport, surgery or by c...

Background Viral infections are pervasive and leading causes of myocarditis. Immune-suppression after chemotherapy increases opportunistic infections, but the incidence of virus-induced myocarditis is unknown. Objective An unbiased, blinded screening for RNA viruses was performed after chemotherapy with correlation to cardiac function. Methods Hi...

Viruses have devised highly effective approaches that modulate the host immune response, blocking immune responses that are designed to eradicate viral infections. Over millions of years of evolution, virus-derived immune-modulating proteins have become extraordinarily potent, in some cases working at picomolar concentrations when expressed into su...

Immunopathogenesis in systemic viral infections can induce a septic state with leaky capillary syndrome, disseminated coagulopathy, and high mortality with limited treatment options. Murine gammaherpesvirus-68 (MHV-68) intraperitoneal infection is a gammaherpesvirus model for producing severe vasculitis, colitis and lethal hemorrhagic pneumonia in...

Background: Ischemia-reperfusion injury (IRI) is an antigen-independent, innate immune response to arterial occlusion and ischemia with subsequent paradoxical exacerbation after reperfusion. IRI remains a critical problem after vessel occlusion and infarction or during harvest and surgery in transplants. After transplant, liver IRI (LIRI) contribu...

The availability of solid organs for transplantation remains low and there is a substantial need for methods to preserve the viability of grafted tissues. Suppression of solid-organ transplant rejection has traditionally focused on highly effective T cell inhibitors that block host immune lymphocyte responses. However, persistent and destructive in...

Plasma membrane-associated Toll-like receptor (TLR2 and TLR4) signaling contributes to oral microbe infection-induced periodontitis and atherosclerosis. We recently reported that either TLR2 or TLR4 receptor deficiency alters recognition of a consortium of oral pathogens, modifying host responses in periodontitis and atherosclerosis. We evaluated t...

Serine protease inhibitors are ubiquitous regulators for a multitude of pathways in humans. The serpins represent an ancient pathway now known to be present in all kingdoms and often regulating central pathways for clotting, immunity, and even cancer in man. Serpins have been present from the time of the dinosaurs and can represent a large proporti...

Biochemical fluorogenic and chromogenic assays facilitate real-time study of enzyme function. Based on the principle of enzymatic inhibition, these kinetic assays can be adapted to measure the function of serpins. Compared to traditional, electrophoretic study of serpin inhibitory complex formation, kinetic assays allow for finer temporal resolutio...

Serpins have a wide range of functions in regulation of serine proteases in the thrombotic cascade and in immune responses, representing up to 2–10% of circulating proteins in the blood. Selected serpins also have cross-class inhibitory actions for cysteine proteases in inflammasome and apoptosis pathways. The arterial and venous systems transport...

Serpins function as a trap for serine proteases, presenting the reactive center loop (RCL) as a target for individual proteases. When the protease cleaves the RCL, the serpin and protease become covalently linked leading to a loss of function of both the protease and the serpin; this suicide inhibition is often referred to as a “mouse trap.” When t...

Early damage to transplanted organs initiates excess inflammation that can cause ongoing injury, a leading cause for late graft loss. The endothelial glycocalyx modulates immune reactions and chemokine-mediated haptotaxis, potentially driving graft loss. In prior work, conditional deficiency of the glycocalyx-modifying enzyme N-deacetylase-N-sulfot...

The Myxomavirus-derived protein Serp-1 has potent anti-inflammatory activity in models of vasculitis, lupus, viral sepsis, and transplant. Serp-1 has also been tested successfully in a Phase IIa clinical trial in unstable angina, representing a 'first-in-class' therapeutic. Recently, peptides derived from the reactive center loop (RCL) have been de...

Aims: Atrial fibrillation (AF) ablation is associated with increased circulating markers of inflammation. Innate immune, or inflammation, pathways up-regulate mononuclear cell responses and may increase risk for recurrent arrhythmia. Chemokines and serine protease coagulation pathways both activate innate immune responses. Here, we measured inflam...

Celecoxib is known to alter the preferred position of SULT2A1-catalyzed sulfonation of 17β-estradiol (17β-E2) and other estrogens from the 3- to the 17-position. Understanding the effects of celecoxib on estrogen sulfonation is of interest in the context of the investigational use of celecoxib to treat breast cancer. This study examined the effects...

Periodontal disease (PD) and atherosclerotic vascular disease (ASVD) are both chronic inflammatory diseases with a polymicrobial etiology and have been epidemiologically associated. The purpose is to examine whether periodontal bacteria that infect the periodontium, can also infect vascular tissues and enhance pre-existing early aortic atherosclero...

Serpins regulate coagulation and inflammation, binding serine proteases in suicide inhibitory complexes. Target proteases cleave the serpin reactive center loop (RCL) scissile P1-P1' bond resulting in serpin-protease suicide inhibitory complexes. This inhibition requires a near full-length serpin sequence. Myxomavirus Serp-1 inhibits thrombolytic a...

Aim: Ser ine p rotease in hibitors ( Serpins ) regulate key clotting and inflammatory pathways. Two anti-inflammatory Serpins , neuroserpin (NSP) and Serp-1 markedly reduce arterial inflammation and plaque growth in a rodent aortic transplant vasculitis model after single dose infusion. NSP is a mammalian serpin that inhibits thrombolytic proteases...

Background: Transplant allograft vasculopathy (TAV) is the leading cause for late transplant organ loss. TAV is induced by activation and invasion of inflammatory monocytes and T cells in response to chemokine binding to glycosaminolycans (GAGs) in the endothelial glycocalyx. We investigated the effect of inhibiting heparin sulfate (HS-GAG) / chemo...

Celecoxib has been reported to switch the human SULT2A1-catalyzed sulfonation of 17β-estradiol (17β-E2) from the 3- to the 17-position. The effects of celecoxib on the sulfonation of selected steroids catalyzed by human SULT2A1 were assessed through in vitro and in silico studies. Celecoxib inhibited SULT2A1-catalyzed sulfonation of dehydroepiandro...

Giant cell arteritis (GCA) and Takayasu's disease are inflammatory vasculitic syndromes (IVS) causing sudden blindness and widespread arterial obstruction and aneurysm formation. Glucocorticoids and aspirin are mainstays of treatment, predominantly targeting T cells. Serp-1, a Myxomavirus-derived serpin, blocks macrophage and T cells in a wide rang...

Serine protease inhibitors, termed serpins, regulate myriad physiological processes in the mammalian body from thrombotic and thrombolytic pathways to inflammation, angiogenesis, hormone transport, and hypertension. The large percentage of serpins among the plasma proteins in the circulating blood as in the case of plasminogen activators, the funct...

Thrombotic occlusion of inflammatory plaque in coronary arteries causes myocardial infarction. Treatment with emergent balloon angioplasty (BA) and stent implant improves survival, but restenosis (regrowth) can occur. Periodontal bacteremia is closely associated with inflammation and native arterial atherosclerosis, with potential to increase reste...

Abstract Cytosolic sulfotransferases are a superfamily of enzymes that catalyze the transfer of the sulfonic group from 3'-phosphoadenosine-5'-phosphosulfate to hydroxy or amine groups in substrate molecules. The human cytosolic sulfotransferases that have been most studied, namely SULT1A1, SULT1A3, SULT1B1, SULT1E1 and SULT2A1, are expressed in di...

The detrimental effect of cell adhesion on polymer surfaces has been a limiting factor in the medical deployment of many implants. We examined the potential to decrease cell proliferation while Simultaneously increasing mechanical performance through Zn-Al layered double hydroxide (LDH) organically modified with ibuprofen dispersed in poly(L-lactic...

The purpose of this research was to study the intercalation of the anions of Ibuprofen, non-steroidal anti-inflammatory drugs (NSAIDs), α-methyl-4-(2-methylpropyl)-benzene acetic acid into a layer double hydroxide (Zn-Al LDH) to form a new organic-inorganic hybrid intercalated material and the formation of nanocomposite with Poly (1-Lactic acid) (P...