Vibrio parahaemolyticus thermostable direct haemolysin induces non-classical programmed cell death despite caspase activation.

Thermostable direct haemolysin (TDH) is the key virulence factor secreted by the human gastroenteric bacterial pathogen Vibrio parahaemolyticus. TDH is a membrane-damaging pore-forming toxin. It evokes potent cytotoxicity, the mechanism of which still remains under-explored.

Vibrio cholerae Porin OmpU Activates Dendritic Cells via TLR2 and the NLRP3 Inflammasome.

OmpU is one of the major porins of Vibrio cholerae, a Gram-negative human pathogen. Previously, we showed that OmpU stimulates host monocytes and macrophages and induces the production of proinflammatory mediators via activation of the Toll-like receptor 1/2 (TLR1/2)-MyD88-dependent pathways. In the present study, we show that OmpU activates murine dendritic cells (DCs) via activation of the TLR2-mediated pathway and the NLRP3 inflammasome, leading to the production of proinflammatory cytokines and DC maturation.

Pore formation-independent cell death induced by a β-barrel pore-forming toxin.

Vibrio cholerae cytolysin (VCC) is a β-barrel pore-forming toxin (β-PFT). It exhibits potent hemolytic activity against erythrocytes that appears to be a direct outcome of its pore-forming functionality. However, VCC-mediated cell-killing mechanism is more complicated in the case of nucleated mammalian cells.

Modulation of host cellular responses by gram-negative bacterial porins.

The outer membrane of a gram-negative bacteria encapsulates the plasma membrane thereby protecting it from the harsh external environment. This membrane acts as a sieving barrier due to the presence of special membrane-spanning proteins called "porins." These porins are β-barrel channel proteins that allow the passive transport of hydrophilic molecules and are impermeable to large and charged molecules.

Immunoporosis: Role of Innate Immune Cells in Osteoporosis.

Osteoporosis or porous bone disorder is the result of an imbalance in an otherwise highly balanced physiological process known as 'bone remodeling'. The immune system is intricately involved in bone physiology as well as pathologies. Inflammatory diseases are often correlated with osteoporosis.

Evolution of sex-specific heat stress tolerance and larval Hsp70 expression in populations of Drosophila melanogaster adapted to larval crowding.

The ability to tolerate temperature stress is an important component of adult fitness. In holometabolous insects like Drosophila melanogaster, adult stress resistance can be affected by growth conditions experienced during the larval stages. Although evolution under crowded larval conditions is known to lead to the correlated evolution of many adult traits, its consequences on adult heat stress tolerance have not been investigated.

Salmonella Typhimurium Adhesin OmpV Activates Host Immunity To Confer Protection against Systemic and Gastrointestinal Infection in Mice.

Salmonella enterica Typhimurium is a rod-shaped Gram-negative bacterium that mostly enters the human body through contaminated food. It causes a gastrointestinal disorder called salmonellosis in humans and typhoid-like systemic disease in mice. OmpV, an outer membrane protein of S.

Outer membrane protein OmpV mediates Salmonella enterica serovar typhimurium adhesion to intestinal epithelial cells via fibronectin and α1β1 integrin.

Salmonella typhimurium is an invasive Gram-negative enteric bacterium, which causes salmonellosis, a type of gastroenteritis in humans and typhoid-like symptoms in mice. Upon entering through the contaminated food and water, S. typhimurium adheres, colonises, and invades intestinal epithelial cells (IECs) of the small intestine.

Effector SteA Suppresses Proinflammatory Responses of the Host by Interfering With IκB Degradation.

serovar Typhimurium is known to cause its virulence by secreting various effector proteins directly into the host cytoplasm via two distinct type III secretion systems (T3SS-1 and T3SS-2). Generally, T3SS-1-delivered effectors help Typhimurium in the early phases of infection including invasion and immune modulation of the host cells, whereas T3SS-2 effectors mainly help in the survival of Typhimurium within the host cells including maintenance of -containing vacuole, replication of the bacteria, and dissemination. Some of the effectors are secreted via both T3SS-1 and T3SS-2, suggesting their role in distinct phases of infection of host cells.

OmpU Mediates CD36-Dependent Reactive Oxygen Species Generation Triggering an Additional Pathway of MAPK Activation in Macrophages.

OmpU, one of the porins of Gram-negative bacteria , induces TLR1/2-MyD88-NF-κB-dependent proinflammatory cytokine production by monocytes and macrophages of human and mouse origin. In this study, we report that in both the cell types, OmpU-induced proinflammatory responses involve activation of MAPKs (p38 and JNK). Interestingly, we observed that in OmpU-treated macrophages, p38 activation is TLR2 dependent, but JNK activation happens through a separate pathway involving reactive oxygen species (ROS) generation by NADPH oxidase complex and mitochondrial ROS.

Differential Recognition of OmpU by Toll-Like Receptors in Monocytes and Macrophages for the Induction of Proinflammatory Responses.

is a human pathogen, and it is a major cause of severe gastroenteritis in coastal areas. OmpU is one of the major outer membrane porins of Host-immunomodulatory effects of OmpU (VpOmpU) have not been elucidated yet. In this study, in an effort towards characterizing the effect of VpOmpU on innate immune responses of the host, we observed that VpOmpU is recognized by the Toll-like receptor 1/2 (TLR1/2) heterodimer in THP-1 monocytes but by both TLR1/2 and TLR2/6 heterodimers in RAW 264.

PRR Function of Innate Immune Receptors in Recognition of Bacteria or Bacterial Ligands.

Recognition of a bacterial attack is the first and the most important step in clearing the bacteria from the body of the host. Towards this, the host innate immune system employs pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs), nucleotide-binding leucine-rich repeat-containing receptors (NLRs) and scavenger receptors (SRs) present mostly in innate immune cells. These receptors sense the presence of bacteria and help in spreading the signal to the host, which results in recruitment of other immune cells leading to the elimination of the bacteria from the system.

Poly(l-lysine)-Coated Liquid Crystal Droplets for Cell-Based Sensing Applications.

Exploring intermolecular interactions in the presence of biomolecules that dictate director configurations of liquid crystals (LCs) enables new techniques for optically probing complex biological phenomena and realizing new classes of sensors and actuators. However, the design of a new approach by probing direct protein-LC interactions (in aqueous media) that can mimic chemico-biological interactions at the cellular level remains elusive. Here, we present a simple method to produce biocompatible LC droplets through poly(l-lysine) (PLL)-LC interactions in situ for reporting the presence of cells and monitoring the real-time interaction of cells with their environments that are mediated by topological defects in those droplets.

Vibrio cholerae Porin OmpU Induces Caspase-independent Programmed Cell Death upon Translocation to the Host Cell Mitochondria.

Porins, a major class of outer membrane proteins in Gram-negative bacteria, primarily act as transport channels. OmpU is one of the major porins of human pathogen, Vibrio cholerae. In the present study, we show that V.

Vibrio cholerae porin OmpU induces LPS tolerance by attenuating TLR-mediated signaling.

Porins can act as pathogen-associated molecular patterns, can be recognized by the host immune system and modulate immune responses. Vibrio choleraeporin OmpU aids in bacterial survival in the human gut by increasing resistance against bile acids and anti-microbial peptides. V.

Vibrio cholerae porin OmpU mediates M1-polarization of macrophages/monocytes via TLR1/TLR2 activation.

Polarization of the monocytes and macrophages toward the M1 and M2 states is important for hosts' defense against the pathogens. Moreover, it plays a crucial role to resolve the overwhelming inflammatory responses that can be harmful to the host. Polarization of macrophages/monocytes can be induced by pathogen-associated molecular patterns (PAMPs).

Transmembrane oligomeric form of Vibrio cholerae cytolysin triggers TLR2/TLR6-dependent proinflammatory responses in monocytes and macrophages.

Vibrio cholerae cytolysin (VCC) kills target eukaryotic cells by forming transmembrane oligomeric β-barrel pores. Once irreversibly converted into the transmembrane oligomeric form, VCC acquires an unusual structural stability and loses its cytotoxic property. It is therefore possible that, on exertion of its cytotoxic activity, the oligomeric form of VCC retained in the disintegrated membrane fractions of the lysed cells would survive within the host cellular milieu for a long period, without causing any further cytotoxicity.

Vibrio cholerae porin OmpU induces pro-inflammatory responses, but down-regulates LPS-mediated effects in RAW 264.7, THP-1 and human PBMCs.

Vibrio cholerae porin OmpU plays a crucial role in the survival of the organism in the human gut. Various observations suggest critical involvement of OmpU in V. cholerae pathogenesis.

Generation of HIV-1 based bi-cistronic lentiviral vectors for stable gene expression and live cell imaging.

The study of protein-protein interactions, protein localization, protein organization into higher order structures and organelle dynamics in live cells, has greatly enhanced the understanding of various cellular processes. Live cell imaging experiments employ plasmid or viral vectors to express the protein/proteins of interest fused to a fluorescent protein. Unlike plasmid vectors, lentiviral vectors can be introduced into both dividing and non dividing cells, can be pseudotyped to infect a broad or narrow range of cells, and can be used to generate transgenic animals.

Refolding and functional assembly of the Vibrio cholerae porin OmpU recombinantly expressed in the cytoplasm of Escherichia coli.

OmpU is one of the major outer membrane porins of Vibrio cholerae. OmpU has been biochemically characterized previously for its 'porin'-property. However, previous studies have used the OmpU protein extracted from the bacterial outer membrane envelope fractions.

Lentiviral mediated transgenesis by in vivo manipulation of spermatogonial stem cells.

This report describes a technique for the generation of transgenic mice by in vivo manipulation of spermatogonial stem cells with a high rate of success. Spermatogonial stem cells (SSCs) in pre-pubescent animals were infected in vivo with recombinant lentiviruses expressing EGFP-f and mated with normal females. All male pre-founder mice produced transgenic pups with an overall success rate of over 60%.

Effects of citral, a naturally occurring antiadipogenic molecule, on an energy-intense diet model of obesity.

Objectives: Retinaldehyde inhibits adipogenesis, increases metabolic rate, reduces weight gain, and improves tolerance to a glucose load. We assessed the effects of citral - an inhibitor of retinaldehyde dehydrogenase (the primary enzyme metabolizing retinaldehyde), on body weight, glucose tolerance, fasting plasma glucose and insulin levels, metabolic rate, adipocyte size, and morphology in a diet-induced model of obesity.

Materials And Methods: Out of the 5 groups of 6-week-old male Sprague-Dawley rats, 4 were maintained on an energy-intense, palatable, diet for a period of - 42 days, while 1 served as the control.

Selective delivery of beta cell antigen to dendritic cells in vivo leads to deletion and tolerance of autoreactive CD8+ T cells in NOD mice.

Type 1 diabetes (T1D) is an autoimmune disease resulting from defects in central and peripheral tolerance and characterized by T cell-mediated destruction of islet beta cells. Cytotoxic CD8(+) T cells, reactive to beta cell antigens, are required for T1D development in the NOD mouse model of the disease, and CD8(+) T cells specific for beta cell antigens can be detected in the peripheral blood of T1D patients. It has been evident that in nonautoimmune-prone mice, dendritic cells (DCs) present model antigens in a tolerogenic manner in the steady state, e.