Biology subjects

Mondal, S.

Publications and source records attributed to Mondal, S..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Comparative Analysis of TG/CA Repeats in Sixteen Primate Genomes Reveals the Dynamics and Role of TG/CA Repeats in the Human Genome

Among the different microsatellite sequences found in the human genome, the dinucleotide TG/CA repeats are one of the most abundant, exhibiting multifaceted functional roles. Availability of several primate genomes offers relevant datasets for studying the evolution and function of these repeats in non-human primates and human genome. Using pairwise genomic alignments, genome-wide analysis of these repeats was performed in human and sixteen other primate genomes. The total number of these repeats and expansion of medium (12[≤] n< 23) and long (n[≥]23) (TG/CA)n repeats was significantly higher in human than other primates. Further, other dinucleotide repeats like TA were found in the orthologous genomic regions in other primates. Thus, selection, elongation and a selective process of conversion of other dinucleotide repeats in primates to TG/CA repeats in humans was apparent and presented in this study as a comprehensive model for the dynamics and role of TG/CA repeats in the human genome.

genomics↗

bioRxiv2023

High-quality genome assemblies provide clues on the evolutionary advantage of blue peafowl over green peafowl

An intriguing example of differential adaptability is the case of two Asian peafowl species, Pavo cristatus (blue peafowl) and Pavo muticus (green peafowl), where the former has a "Least Concern" conservation status and the latter is an "Endangered" species. To understand the genetic basis of this differential adaptability of the two peafowl species, a comparative analysis of these species is much needed to gain the genomic and evolutionary insights. Thus, we constructed a high-quality genome assembly of blue peafowl with an N50 value of 84.81 Mb (pseudochromosome-level assembly), and a high-confidence coding gene set to perform the genomic and evolutionary analyses of blue and green peafowls with 49 other avian species. The analyses revealed adaptive evolution of genes related to neuronal development, immunity, and skeletal muscle development in these peafowl species. Major genes related to axon guidance showed adaptive evolution in peafowl species. However, blue peafowl showed the presence of 42% more coding genes compared to the green peafowl along with a higher number of unique gene clusters, segmental duplicated genes and expanded gene families, and comparatively higher evolution in neuronal and developmental pathways. Blue peafowl also showed longer branch length compared to green peafowl in the species phylogenetic tree. These genomic insights obtained from the high-quality genome assembly of P. cristatus constructed in this study provide new clues on the superior adaptability of the blue peafowl over green peafowl despite having a recent species divergence time.

genomics↗

bioRxiv2022

Bimodal 1/f noise and anticorrelation between DNA-Water and DNA-Ion energy fluctuations

Coupling between the fluctuations of DNA and its surroundings consisting of water and ions in solution remains poorly understood and relatively less investigated as compared to proteins. Here, with the help of molecular dynamics simulations and statistical mechanical analyses, we explore the dynamical coupling between DNA, water, and counterions through correlations among respective energy fluctuations in both double (ds-) and single-stranded (ss-) DNA solutions. Fluctuations in the collective DNA-Water and DNA-Ion interaction energies are found to be strongly anti-correlated across all the systems. The fluctuations of DNA self-energy, however, are weakly coupled to DNA-water and DNA-ion interactions in ds-DNA. An enhancement of the DNA-water coupling is observed in ss-DNA, where the system is less rigid. All the interaction energies exhibit 1/f noise in their energy power spectra with surprisingly prominent bimodality in the DNA-water and DNA-ion fluctuations. The nature of the energy spectra appears to be indifferent to the relative rigidity of the DNA. We discuss the role of the observed correlations in ion-water motions on a DNA duplex in the experimentally observed anomalous slow dielectric relaxation and solvation dynamics, and in furthering our understanding of the DNA energy landscape. TOC GRAPHIC O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/520228v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@806797org.highwire.dtl.DTLVardef@110c9corg.highwire.dtl.DTLVardef@1531566org.highwire.dtl.DTLVardef@1a1fe12_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2022

Comparative Radiopathology of Male Reproductive Organs in Sprague Dawley Rats Administered with Curcuma longa and Ocimum sanctum Against Acute Gamma Irradiation

ObjectiveThe study was designed to evaluate the deleterious e{square}ects of acute lethal gamma irradiation on male reproductive organs of Sprague Dawley rats and the radioprotective potential by Curcuma longa and Ocimum sanctum in experimental set up. Methods25 Male Spraque Dawley rats were taken and randomized into 5 groups (T1, T2, T3, T4, T5). Each group containing 5 animals. The groups were named as Group T1 (Negative Control), Group T2 (irradiation positive control), Group T3 (irradiation and Curcuma longa), Group T4 (irradiation and Ocimum sanctum), Group T5 (irradiation, Curcuma longa and Ocimum sanctum). The rats in groups T1 and T2 were given a daily dosage of normal saline for 14 days. Group T3 and T4 rats received aqueous extracts of Curcuma longa (40 mg/kg) and Ocimum sanctum (40 mg/kg), respectively, whereas group T5 rats received a combination of aqueous extracts of Curcuma longa (40 mg/kg) and Ocimum sanctum (40 mg/kg) for 14 days. prior to gamma irradiation. Animals of group T2, T3, T4, T5 were irradiated with 10 Gy of {gamma} - radiation on 15th day. ResultsExposure of animals to 10 Gy gamma radiation resulted in significant decrease in body weight and testicular weight. Histopathological observations revealed testicular degenerative changes in the seminiferous tubules with primary spermatocytes being most affected and epididymis showed decreased spermatids density with cell debris in the lumen. Pretreatment with Curcuma longa at 40mg/kg for 14 days alleviated the radiation induced pathological changes in testis and epididymis. Curcuma longa demonstrated much better protective effect in combination with Ocimum sanctum in alleviating the radio pathological changes showing the possibility of synergistic effect. However, administration of Ocimum sanctum alone at 40mg/kg for 14 days did not reveal any significant radioprotective property after histomorphological evaluation. ConclusionGamma irradiation of 10 Gy induces severe radio pathological damage to organs of male reproductive system of Spraque Dawley rats. Pre-treatment with Curcuma longa prior to radiotherapy may be effective in preventing radiation-induced damage in the male reproductive organs. Better radioprotection can be achieved with the combination of Curcuma longa and Ocimum sanctum than using alone.

pathology↗

bioRxiv2022

DIP2 is a unique regulator of diacylglycerol lipid homeostasis in eukaryotes

Chain-length specific subsets of diacylglycerol (DAG) lipids are proposed to regulate differential physiological responses ranging from signal transduction to modulation of the membrane properties. However, the mechanism or molecular players regulating the subsets of DAG species remains unknown. Here, we uncover the role of a conserved eukaryotic protein family, DISCO-interacting protein 2 (DIP2) as a homeostatic regulator of a chemically distinct subset of DAGs using yeast, fly and mouse models. Genetic and chemical screens along with lipidomics analysis in yeast reveal that DIP2 prevents the toxic accumulation of specific DAGs in the logarithmic growth phase, which otherwise leads to endoplasmic reticulum stress. We also show that the fatty acyl-AMP ligase-like domains of DIP2 are essential for the redirection of the flux of DAG subspecies to storage lipid, triacylglycerols. Such modulation of selective DAG abundance by DIP2 is found to be crucial for optimal vacuole-membrane fusion and consequently osmoadaptation in yeast. Thus, the study illuminates an unprecedented DAG metabolism route and provides new insights on how cell fine-tunes DAG subspecies for cellular homeostasis and environmental adaptation.

biochemistry↗

bioRxiv2021

Multivalent Interactions between Molecular Components Involved in Clathrin Independent Endocytosis Drive Protein Phase Separation

A specific group of transmembrane receptors, including the {beta}1-adrenergic receptor ({beta}1-AR), is internalized through a non-clathrin pathway known as Fast Endophilin Mediated Endocytosis (FEME). A key question is: how does the endocytic machinery assemble and how is it modulated by activated receptors during FEME. Here we show that endophilin, a major regulator of FEME, undergoes a phase transition into liquid-like condensates, which facilitates the formation of multi-protein assemblies by enabling the phase partitioning of endophilin binding proteins. The phase transition can be triggered by specific multivalent binding partners of endophilin in the FEME pathway such as the third intracellular loop (TIL) of the {beta}1-AR, and the C-terminal domain of lamellipodin (LPD). Other endocytic accessory proteins can either partition into, or target interfacial regions of, these condensate droplets. On the membrane, TIL promotes protein clustering in the presence of endophilin and LPD C-terminal domain. Our results demonstrate how the multivalent interactions between endophilin, LPD, and TIL regulate protein assembly formation on the membrane, providing mechanistic insights into the priming and initiation steps of FEME.

biophysics↗

bioRxiv2021

Essential Loop Dynamics Modulates Catalytic Activity in α-Chymotrypsin

Conformational dynamics of macromolecules including enzymes are essential for their function. The present work reports the role of essential dynamics in alpha-chymotrypsin (CHT) which correlates with its catalytic activity. Detailed optical spectroscopy and classical molecular dynamics (MD) simulation were used to study thermal stability, catalytic activity and dynamical flexibility of the enzyme. The study of the enzyme kinetics reveals an optimum catalytic efficiency at 308K. Polarization gated fluorescence anisotropy with 8-anilino-1-napthelene sulfonate (ANS) have indicated increasing flexibility of the enzyme with an increase in temperature. Examination of the structure of CHT reveal the presence of five loop regions (LRs) around the catalytic S1 pocket. MD simulations have indicated that flexibility increases concurrently with temperature which decreases beyond optimum temperature. Principal component analysis (PCA) of the eigenvectors manifests essential dynamics and gatekeeping role of the five LRs surrounding the catalytic pocket which controls the enzyme activity.

biophysics↗

bioRxiv2021

A Combined Spectroscopic and Molecular Modeling Study on Structure-Function-Dynamics under Chemical Modification: Alpha-Chymotrypsin with Formalin Preservative

Enzyme conformations can be altered via modification of its amino acid residues, side chains and large-scale domain modifications, which are closely linked to its function. Herein, we have addressed the role of residue modification in catalytic activity and molecular recognition of an enzyme alpha-chymotrypsin (CHT) in presence of covalent cross-linker formalin. Optical spectroscopy studies exhibit reduced catalytic activity of the enzyme with increased formalin concentration. Polarization gated anisotropy studies of a fluorophore 8-anilino-1- napthelenesulfonic acid (ANS) in CHT show a dip rise pattern in presence of formalin which is consistent with the generation of multiple ANS binding sites in the enzyme owing to modifications of its local amino acid residues. Molecular docking study on minimal local residue modifications in CHT reveals formation of a stable enzyme-substrate complex even with the serine-histidine cross-linked enzyme which prohibits product formation giving rise to reduced catalytic activity.

biophysics↗

bioRxiv2021

A universal pocket in FAALs ensures redirection of fatty acid pool away from CoA-based activation

Fatty acyl-AMP ligases (FAALs) channelize fatty acids towards biosynthesis of virulent lipids in mycobacteria and other pharmaceutically or ecologically important polyketides and lipopeptides in other microbes. They do so by bypassing the ubiquitous coenzyme A-dependent activation and rely on the acyl carrier protein-tethered 4-phosphopantetheine (holo-ACP). The molecular basis of how FAALs strictly reject chemically identical and abundant acceptors like coenzyme A (CoA) and accept holo-ACP unlike other members of the ANL superfamily remains elusive. We show FAALs have plugged the promiscuous canonical CoA-binding pockets and utilize highly selective alternative binding sites. These alternative pockets can distinguish adenosine 3, 5-bisphosphate-containing CoA from holo-ACP and thus FAALs can distinguish between CoA and holo-ACP. These exclusive features helped identify the omnipresence of FAAL-like proteins and their emergence in plants, fungi, and animals with unconventional domain organisations. The universal distribution of FAALs suggests they are parallelly evolved with FACLs for ensuring a CoA-independent activation and redirection of fatty acids towards lipidic metabolites.

biochemistry↗

bioRxiv2021

Structural heterogeneity in biliverdin modulates spectral properties of Sandercyanin fluorescent protein

Sandercyanin, a blue homo-tetrameric lipocalin protein purified from Canadian walleye (Stizostedion vitreus), is the first far-red fluorescent protein reported in vertebrates(1-3). Sandercyanin binds non-covalently to biliverdin IX (BLA) and fluoresces at 675nm on excitation at 375nm and 635nm(1). Sandercyanin fluorescence can be harnessed for many in vivo applications when engineered into a stable monomeric form. Here, we report the spectral properties and crystal structures of engineered monomeric Sandercyanin-BLA complexes. Compared to wild-type protein, monomeric Sandercyanin ([~]18kDa) binds BLA with similar affinities and show a broad red-shifted absorbance spectra but possess reduced quantum efficiency. Crystal structures reveal D-ring pyrrole of BLA rotated around the C14-C15 bond, which is stabilized by neighboring aromatic residues and increased water-mediated polar contacts in the BLA-binding pocket. A tetrameric Sandercyanin variant (Tyr-142-Ala) co-displaying red- and far-red absorbing states, and reduced fluorescence shows similar conformational changes in BLA binding pocket. Our results suggest that D-ring flexibility of BLA and its rearrangement reduces the fluorescence quantum-yield of monomeric Sandercyanin. Structures of monomeric Sandercyanin could be utilized as prototypes to generate bright BLA-inducible fluorescent proteins. Further, our study postulates a mechanism for modulating photo-states in BLA-bound lipocalins, known only in phytochromes till date. Significance StatementSandercyanin is a tetrameric red fluorescent protein from a blue variant of walleye (Stizostedion vitreum) that binds to biliverdin IX (BLA). Its biophysical properties and structures have been published earlier(1). A bright and stable monomeric Sandercyanin could be utilized as a fusion protein for fluorescence-based applications. Here we report the first structures and spectral properties of fluorescent monomeric Sandercyanin-BLA complexes and describe the molecular basis of modulated spectral properties due to rotated D-ring pyrrole around C14-C15 bond and re-shuffling of BLA-binding pocket. BLA-bound monomeric Sandercyanin could be engineered into brighter variants for in-vivo applications. Our study also reveals an unfamiliar mechanism in BLA-binding lipocalins that regulates red- and far-red absorbance states.

bioengineering↗

bioRxiv2021

Bacterial hopanoids: a newly identified potent inducer of monocyte to macrophage differentiation

Monocyte to macrophage differentiation is an extremely essential cellular and immunological process aimed to combat the assault of foreign pathogens as well as this process has immense importance in the maintenance of physiological homeostasis. Differentiated macrophage, serving as specialized phagocytes is an indispensable component of innate immunity. Besides this, being a well-documented antigen-presenting cell (APC) macrophages also function as a key regulator of both humoral and cell-mediated immunity: the two integral components of adaptive immunity. Bacterial hopanoids are a primitive analogous of eukaryotic sterols that are established as a prominent immunomodulator. In this study, we have demonstrated the isolation protocol of neutral lipid fractions from different Gram-negative bacteria, and adopting several analytical approaches we proposed that the extracted lipid fractions may contain hopanoid as an active component. We have delved deeper into the biological effect of these probable hopanoids like compounds. Here, by considering the several structural and functional attributes like altered phenotype, expression of macrophage-specific markers, increased intracellular organelles, acquirement of enhanced phagocytic and inflammatory property, induction of autophagy, etc we have established hopanoids as a potential inducer of monocyte to macrophage differentiation. Thus, our study has unraveled a new immunomodulator present in Gram-negative bacteria and would undoubtedly help to understand the intricacies of host-pathogen interaction in a better and conclusive manner.

cell biology↗

bioRxiv2021

Redox Buffering Capacity of Nanomaterials as an Index of ROS-based Therapeutics and Toxicity: A Preclinical Animal Study

Precise control of intracellular redox status, i.e., maintenance of physiological level of reactive oxygen species (ROS) for mediating normal cellular functions (oxidative eustress) while evading the excess ROS stress (distress) is central to the concept of redox medicine. In this regard, engineered nanoparticles with unique ROS generation, transition, or depletion functions have the potential to be the choice of redox therapeutics. However, it is always challenging to estimate whether ROS-induced intracellular events are beneficial or deleterious to the cell. Here, we propose the concept of redox buffering capacity as a therapeutic index of engineered nanomaterials. As a steady redox state is maintained for normal functioning cells, we hypothesize that the ability of a nanomaterial to preserve this homeostatic condition will dictate its therapeutic efficacy. Additionally, the redox buffering capacity is expected to provide information about the nanoparticle toxicity. Here, using citrate functionalized trimanganese tetroxide nanoparticles (C-Mn3O4 NPs) as a model nanosystem we explored its redox buffering capacity in erythrocytes. Furthermore, we went on to study the chronic toxic effect (if any) of this nanomaterial in animal model in order to co-relate with the experimentally estimated redox buffering capacity. This study could function as a framework for assessing the capability of a nanomaterial as redox medicine (whether maintains eustress or damages by creating distress), thus orienting its application and safety for clinical use.

pharmacology and toxicology↗

bioRxiv2021

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↗

bioRxiv2021

Optimized structure of monoubiquitinated FANCD2 (human) at Lys 561: a theoretical approach

Fanconi anaemia pathway repairs inter-strand cross linking damage (ICL) of the DNA. Monoubiquitination of FANCD2 and FANCI is very crucial for ICL repairing. In this work we have tried to understand the monoubiquitinated FANCD2 structure, which facilitates the FANCD2 for binding the damage part of the chromatin. Crystal structure of the monoubiquitinated FANCD2 alone is not available, therefore we have developed the optimized structure of the human monoubiquitinated (Lys 561) FANCD2. As there is no suitable software or web server we have developed a method for building up monoubiquitinated product and validated on simplest monoubiquitinated protein, diubiquitin. We have predicted the structure of human monoubiquitinated FANCD2 by using our method and studied the interaction with DNA by docking studies. Molecular Dynamics (MD) simulation was used to understand the stability of the structure. Large structural differences have been observed between FANCD2 and monoubiquitinated FANCD2. DNA docking studies suggest that the binding site varies for the FANCD2 and monoubiquitinated FANCD2.

bioinformatics↗

bioRxiv2021

Development of Tribo-Electroceutical Fabrics for Potential Application in Self-sanitizing Personal Protective Equipment (PPE)

Attachment of microbial bodies including coronavirus on the surface of personal protective equipment (PPE) is found to be potential threat of spreading infection. Here, we report the development of a novel tribo-electroceutical fabric (TECF) consisting of commonly available materials namely Nylon, and Silicone Rubber (SR) for the fabrication of protective gloves on Nitrile platform, as a model wearable PPE. A small triboelectric device (2 cm x 2 cm) consisting of SR and Nylon on Nitrile can generate more than 20 volt transient or 41 {micro}W output power, which is capable of charging a capacitor up to 65 V in only [~]50 sec. The novelty of the present work relies on the TECF led anti-microbial activity through the generation of an electric current in saline water. The fabrication of TECF based functional prototype gloves can generate hypochlorite ions through the formation of electrolysed water upon rubbing them with saline water. Further a computational modelling has been employed to reveal the optimum structure and mechanistic pathway of anti-microbial hypochlorite generation. Detailed anti-microbial assays have been performed to establish effectiveness of such TECF based gloves to reduce the risk from life threatening pathogen spreading. The present work provides the rationale to consider the studied TECF, or other material with comparable properties, as material of choice for the development of self-sanitizing PPE in the fight against microbial infections including COVID-19.

microbiology↗

bioRxiv2021

Nanoceutical Fabric Prevents COVID-19 Spread through Expelled Respiratory Droplets: A Combined Computational, Spectroscopic and Anti-microbial Study

Centers for Disease Control and Prevention (CDC) warns the use of one-way valves or vents in free masks for potential threat of spreading COVID-19 through expelled respiratory droplets. Here, we have developed a nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanomaterial for potential use as membrane filter in the one way valve for the ease of breathing without the threat of COVID-19 spreading. A detailed computational study revealed that zinc oxide nanoflowers (ZnO NF) with almost two-dimensional petals trap SARS-CoV-2 spike proteins, responsible to attach to ACE-2 receptors in human lung epithelial cells. The study also confirm significant denaturation of the spike proteins on the ZnO surface, revealing removal of virus upon efficient trapping. Following the computational study, we have synthesized ZnO NF on cotton matrix using hydrothermal assisted strategy. Electron microscopic, steady-state and picosecond resolved spectroscopic studies confirm attachment of ZnO NF to the cotton (i.e., cellulose) matrix at atomic level to develop the nanoceutical fabric. A detailed antimicrobial assay using Pseudomonas aeruginosa bacteria (model SARS-CoV-2 mimic) reveals excellent anti-microbial efficiency of the developed nanoceutical fabric. To our understanding the novel nanoceutical fabric used in one-way valve of a face mask would be the choice to assure breathing comfort along with source control of COVID-19 infection. The developed nanosensitized cloth can also be used as antibacterial/anti CoV-2 washable dress material in general. GRAPHICAL ABSTRACT O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY A novel nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanoflower can potentially be used as membrane filter in the one way valve of face mask to assure breathing comfort along with source control of COVID-19 infection. The nanoceutical fabric denatures the SARS-CoV-2 spike protein and makes the microorganism ineffective.

microbiology↗

bioRxiv2021

A Nanoceutical Agent for Chemoprevention of Bilirubin Encephalopathy

BackgroundTargeted degradation of bilirubin in vivo may enable safer and more effective approach to manage incipient bilirubin encephalopathy consequent to severe neonatal hyperbilirubinemia (SNH). This report builds on the use of a spinel structured mixed-valence transition metal oxide (trimanganese tetroxide) nanoparticle duly functionalized with biocompatible ligand citrate (C-Mn3O4 NP) having the ability to degrade bilirubin without photo-activation. MethodThe efficiency of C-Mn3O4 NP in in vivo degradation of serum bilirubin and amelioration of severe bilirubin encephalopathy and associated neurobehavioral changes was evaluated in C57BL/6j animal model of SNH. ResultsOral single dose (0.25 mg kg-1 body weight) of the NPs efficiently reduced serum bilirubin levels (both conjugated and unconjugated) in study mice. It prevents bilirubin-induced neurotoxicity with reduction of SNH as observed by neurobehavioral and movement studies of SNH-mice. Pharmacokinetic data suggests intestinal reabsorption of the NPs and explain sustainable action. Biodistribution, pharmacokinetics, and biocompatibility of the NPs were tested during sub-chronic exposure. ConclusionThus, we report preliminary studies that explore an affordable chemoprevention mechanism to acutely prevent or minimize bilirubin neurotoxicity in newborn infants. IMPACT STATEMENTO_LIDespite several attempts, no pharmaco-therapeutics are available for the treatment of severe neonatal hyperbilirubinemia (SNH) and associated neurotoxicity. C_LIO_LIOur newly developed nanodrug, citrate functionalized Mn3O4 nanoparticles (C-Mn3O4 NPs), can efficiently ameliorate SNH and associated neurotoxicity as investigated in preclinical rodent model. C_LIO_LIChemoprevention effect of the nanodrug is found to be safe and sustainable. C_LIO_LIIf successfully translated into clinical trials, C-Mn3O4 NPs could become the first drug to treat SNH. C_LI

pharmacology and toxicology↗

bioRxiv2020

Naturally secreted bacterial outer membrane vesicles: potential platform for a vaccine against Campylobacter jejuni

Acute diarrheal illness and gastroenteritis caused by Campylobacter jejuni (C. jejuni) infection remain significant public health risks in developing countries with substantial mortality and morbidity in humans, particularly in children under the age of five. Despite improved global awareness in sanitation and hygiene practices, including food safety measures, C. jejuni infections continue to rise even across the developed nations and no vaccine is currently available for humans. Genetic diversities among C. jejuni strains as well as limited understanding of immunological correlates of host protection remain primary impediments for developing an effective vaccine against C. jejuni. Given the role of bacterial outer membrane-associated proteins in intestinal adherence and invasion as well as modulating dynamic interplay between host and pathogens, bacterial outer membrane vesicles (OMVs) have emerged as potential vaccine platforms against a number of enteric pathogens, including C. jejuni. In the present study, we describe a mucosal vaccine strategy using chitosan (CS) coated OMVs (CS-OMVs) to induce specific immune responses against C. jejuni in mice. However, considering the challenges of mucosal delivery of OMVs in terms of exposure to variable pH, risk of enzymatic degradation, rapid gut transit, and low permeability across the intestinal epithelium, we preferentially used CS as a non-toxic, mucoadhesive polymer to coat OMVs. Mucosal administration of CS-OMVs induced high titre of systemic (IgG) and local (secretory IgA) antibodies in mice. The neutralizing ability of secretory IgA (sIgA) produced in the intestine was confirmed by in vitro inhibition of cell adherence and invasion of C. jejuni while in vivo challenge study in OMVs immunized mice showed a significant reduction in cecal colonization of C. jejuni. Moreover, to investigate the immunological correlates of the observed protection, present data suggest OMVs driven T cell proliferation with an increased population of CD4+ and CD8+ T cells. In addition to antibody isotype profile, significant upregulation of IFN-{gamma} and IL-6 gene expression in mesenteric lymph nodes collected from OMVs immunized mice further suggests that mucosal delivery of OMVs promotes a Th1/Th2 mixed type immune responses. Together, we provide strong experimental evidence that as an acellular and non-replicating canonical end product of bacterial secretion, mucosal delivery of OMVs may represent a promising platform for developing an effective vaccine against C. jejuni. Author SummaryDespite the loss of 7.5 million disability-adjusted life years, which is over and above any other globally prevalent enteric or enterotoxigenic pathogens, C. jejuni remains a neglected foodborne pathogen, particularly in tropical countries. Even with the improved global awareness in sanitation and hygiene practices, including food safety measures C. jejuni infections continue to rise globally and no vaccine is currently available for humans. In light of the importance of the diverse cargo selection by bacterial OMVs, the present study describes a mucosal vaccine strategy using chitosan-coated OMVs to induce specific immune responses against C. jejuni in mice. We provide here strong experimental evidence that as a non-replicating canonical end product of bacterial secretion, mucosal delivery of OMVs represents an attractive vaccine platform against C. jejuni.

immunology↗