Different mechanisms of inflammation induced in virus and autoimmune-mediated models of multiple sclerosis in C57BL6 mice.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the human central nervous system (CNS). Neurotropic demyelinating strain of MHV (MHV-A59 or its isogenic recombinant strain RSA59) induces MS-like disease in mice mediated by microglia, along with a small population of T cells. The mechanism of demyelination is at least in part due to microglia-mediated myelin stripping, with some direct axonal injury. Immunization with myelin oligodendrocyte glycoprotein (MOG) induces experimental autoimmune encephalomyelitis (EAE), a mainly CD4(+) T-cell-mediated disease, although CD8(+) T cells may play a significant role in demyelination. It is possible that both autoimmune and nonimmune mechanisms such as direct viral toxicity may induce MS. Our study directly compares CNS pathology in autoimmune and viral-induced MS models. Mice with viral-induced and EAE demyelinating diseases demonstrated similar patterns and distributions of demyelination that accumulated over the course of the disease. However, significant differences in acute inflammation were noted. Inflammation was restricted mainly to white matter at all times in EAE, whereas inflammation initially largely involved gray matter in acute MHV-induced disease and then is subsequently localized only in white matter in the chronic disease phase. The presence of dual mechanisms of demyelination may be responsible for the failure of immunosuppression to promote long-term remission in many MS patients

A proline insertion-deletion in the spike glycoprotein fusion peptide of mouse hepatitis virus strongly alters neuropathology.

Fusion peptides (FPs) in spike proteins are key players mediating early events in cell-to-cell fusion, vital for intercellular viral spread. A proline residue located at the central FP region has often been suggested to have a distinctive role in this fusion event. The spike glycoprotein from strain RSA59 (PP) of mouse hepatitis virus (MHV) contains two central, consecutive prolines in the FP. Here, we report that deletion of one of these proline residues, resulting in RSA59 (P), significantly affected neural cell syncytia formation and viral titers postinfection in vitro. Transcranial inoculation of C57Bl/6 mice with RSA59 (PP) or RSA59 (P) yielded similar degrees of necrotizing hepatitis and meningitis, but only RSA59 (PP) produced widespread encephalitis that extended deeply into the brain parenchyma. By day 6 postinfection, both virus variants were mostly cleared from the brain. Interestingly, inoculation with the RSA59 (P)- carrying MHV significantly reduced demyelination at the chronic stage. We also found that the presence of two consecutive prolines in FP promotes a more ordered, compact, and rigid structure in the spike protein. These effects on FP structure were due to proline\u27s unique stereochemical properties intrinsic to its secondary amino acid structure, revealed by molecular dynamics andNMRexperiments.Wetherefore propose that the differences in the severity of encephalitis and demyelination between RSA59 (PP) and RSA59 (P) arise from the presence or absence, respectively, of the two consecutive prolines in FP. Our studies define a structural determinant of MHV entry in the brain parenchyma important for altered neuropathogenesis. © 2019 Singh et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc

Expression and characterization of a potential exopolysaccharide from a newly isolated halophilic thermotolerant bacteria Halomonas nitroreducens strain WB1

The halophilic bacterial strain WB1 isolated from a hydrothermal vent was taxonomically characterized using multiple proxies, as Halomonas nitroreducens strain WB1. When grown on malt extract/yeast extract (MY) medium, it produced large quantities of exopolysaccharide (EPS). The polymer was synthesized at a higher rate during the log and early stationary phases. The anionic polysaccharide is primarily composed of glucose, mannose, and galactose. The studied EPS was highly viscous and had pseudoplastic nature. The EPS was found to be a mixture of three polysaccharides under FT-IR, which makes it less labile to environmental diagenesis. It also has emulsifying and antioxidant activity along with the binding capacity to heavy metals. The EPS has unique and interesting physical and chemical properties, which are different from earlier reported exo-polysaccharides produced by different bacterial genus. This suggests that the extreme geological niches like hypersaline, hyperthermal, hypothermal, and oligophilic environments, which are not well studied so far, can offer extensive and potential resources for medical, biotechnological and industrial applications. The study clearly showed that the thermal springs from the temperate region can be a potent source of many such industrially important microbial genera and need further detailed studies to be carried out

Norbornene-Derived Poly‑d‑lysine Copolymers as Quantum Dot Carriers for Neuron Growth

Synthesis of norbornene derived phosphonate (<b>1</b>), poly-d-lysine (<b>2</b>), and phopholipid (<b>3</b>) monomers and their complete characterizations are studied. Ring-opening metathesis polymerizations (ROMP) of monomers (<b>1</b>–<b>3</b>) produce well-defined copolymers, <b>CP</b>_<b>1</b> and <b>CP</b>_<b>2</b>. ¹H NMR along with FT-IR spectroscopy characterization confirms the copolymer formation, while gel permeation chromatography (GPC) analysis suggests the formation of polymers with fairly narrow molecular weight distributions. Upon following the well-known ligand exchange methods these copolymers produce CdSe-bound copolymers, <b>CP</b>_<b>3</b> and <b>CP</b>_<b>4</b>. Dynamic light scattering and transmission electron microscopy measures the size of these CdSe bound copolymers, while ³¹P NMR suggests the formation of <b>CP</b>_<b>3</b> and <b>CP</b>_<b>4</b>. The results from the experiments of these copolymers on Neuro2A cells suggest that the novel PDL-anchored nanomaterial show their ability to polarize neuronal growth and differentiation

Norbornene Derived Doxorubicin Copolymers as Drug Carriers with pH Responsive Hydrazone Linker

The synthesis and complete characterization of both norbornene-derived doxorubicin (mono <b>1</b>) and polyethylene glycol (mono <b>2</b>) monomers are clearly described, and their copolymerization by ring-opening metathesis polymerization (ROMP) to get the block copolymer (<b>COPY-DOX</b>) is vividly elaborated. The careful design of these conjugates exhibits properties like well-shielded drug moieties and well-defined nanostructures; additionally, they show solubility in both water and biological medium and also have the important tendency of rendering acid-triggered drug release. The drug release profile suggests the importance of having the hydrazone linker that helps to release the drug exactly at the mild acidic conditions resembling the pH of the cancerous cells. It is also observed that the drug release from micelles of <b>COPY-DOX</b> is significantly accelerated at a mildly acidic pH of 5.5–6, compared to the physiological pH of 7.4, suggesting the pH-responsive feature of the drug delivery system with hydrazone linkages. Confocal laser scanning microscopy (CLSM) measurements indicate that these <b>COPY-DOX</b> micelles are easily internalized by living cells. MTT assays against HeLa and 4T cancer cells showing <b>COPY-DOX</b> micelles have a high anticancer efficacy. All of these results demonstrate that these polymeric micelles that self-assembled from <b>COPY-DOX</b> block copolymers have great scope in the world of medicine, and they also symbolize promising carriers for the pH-triggered intracellular delivery of hydrophobic anticancer drugs

Two Consecutive Prolines in the Fusion Peptide of Murine β-Coronavirus Spike Protein Predominantly Determine Fusogenicity and May Be Essential but Not Sufficient to Cause Demyelination

Combined in silico, in vitro, and in vivo comparative studies between isogenic-recombinant Mouse-Hepatitis-Virus-RSA59 and its proline deletion mutant, revealed a remarkable contribution of centrally located two consecutive prolines (PP) from Spike protein fusion peptide (FP) in enhancing virus fusogenic and hepato-neuropathogenic potential. To deepen our understanding of the underlying factors, we extend our studies to a non-fusogenic parental virus strain RSMHV2 (P) with a single proline in the FP and its proline inserted mutant, RSMHV2 (PP). Comparative in vitro and in vivo studies between virus strains RSA59(PP), RSMHV2 (P), and RSMHV2 (PP) in the FP demonstrate that the insertion of one proline significantly resulted in enhancing the virus fusogenicity, spread, and consecutive neuropathogenesis. Computational studies suggest that the central PP in Spike FP induces a locally ordered, compact, and rigid structure of the Spike protein in RSMHV2 (PP) compared to RSMHV2 (P), but globally the Spike S2-domain is akin to the parental strain RSA59(PP), the latter being the most flexible showing two potential wells in the energy landscape as observed from the molecular dynamics studies. The critical location of two central prolines of the FP is essential for fusogenicity and pathogenesis making it a potential site for designing antiviral

Amphiphilic Homopolymer Vesicles as Unique Nano-Carriers for Cancer Therapy

A unique polymersome from amphiphilic, norbornene-derived thiobarbiturate homopolymers (<b>NDTH</b>) and its application as nanocarrier for cancer therapy are elaborately discussed. Various experiments like structural characterizations, control studies, cell viability studies, encapsulation studies, and MTT assay against 4T cancer cells are performed on these <b>NDTH</b> polymersomes to substantiate our claims. All of these results demonstrate that these self-assembled <b>NDTH</b> vesicles have great scope in the world of medicine, and they also symbolize promising carriers for the stimuli-triggered intracellular delivery of hydrophobic drugs