Transgenic mouse models support a protective role of type I IFN response in SARS-CoV-2 infection-related lung immunopathology and neuroinvasion.

Type I interferon (IFN-I) response is the first line of host defense against invading viruses. In the absence of definite mouse models, the role of IFN-I in SARS-CoV-2 infection remains perplexing. Here, we develop two mouse models, one with constitutively high IFN-I response (hACE2; Irgm1-/-) and the other with dampened IFN-I response (hACE2; Ifnar1-/-), to comprehend the role of IFN-I response. We report that hACE2; Irgm1-/- mice are resistant to lethal SARS-CoV-2 infection. In contrast, a severe SARS-CoV-2 infection along with immune cell infiltration, cytokine storm, and enhanced pathology is observed in the lungs and brain of hACE2; Ifnar1-/- mice. The hACE2; Irgm1-/-Ifnar1-/- double-knockout mice display loss of the protective phenotype observed in hACE2; Irgm1-/- mice, suggesting that heightened IFN-I response accounts for the observed immunity. Taking the results together, we demonstrate that IFN-I protects from lethal SARS-CoV-2 infection, and Irgm1 (IRGM) could be an excellent therapeutic target against SARS-CoV-2.

Post craniotomy pain management in Copenhagen rat by intraperitoneal or oral dosage of Tramadol: a comparative evaluation.

Calvarial craniotomy in animal models involves pain and distress. Moderate to severe pain in laboratory animals requires adequate pain management strategies. According to previous studies, the options available for suitable analgesia for rat calvarial craniotomy are very few. For most analgesic treatments, injectable routes of administration are predominantly used. However, these routes require restraining the animals, which may cause unnecessary pain, distress and suffering. As a well-fare measure, we focused on pain management by oral administration of analgesia. In this particular study, which is a sub-study of a major experiment on bone regeneration with different polymeric scaffold materials, we have compared the analgesic efficacy of intraperitoneal (I/P) and oral administration of tramadol (10 mg/kg) over a period of 96 h post-surgery in rat craniotomy models. The focus of our study is to evaluate the potential pain reduction efficacy of orally administered Tramadol without any restraining involved. We have used various non-invasive methods to assess the pain-alleviating efficacy of tramadol administered through different methods. We found that the efficacy of oral administration of tramadol is comparable to I/P administration in alleviating pain. Additionally, oral administration through drinking water has the benefit of not putting the animal under unwanted restraining stress.

Glycoprotein Injectable Hydrogels Promote Accelerated Bone Regeneration through Angiogenesis and Innervation.

Glycoproteins are gaining prominence as multifunctional biomaterials. The study reports development of glycoprotein mucin as biomaterial promoting bone regeneration. Mucin 1 deletion has resulted in stiffer femoral bones with scarce presence of osteoblasts in trabecular linings and its role has been established in determining bone mass and mineralization. Limited information about its structure limits its processability, exploration as biomaterial, which is discussed in this study. The role of mucin in ECM (extracellular cellular matrix) formation validated by RNA sequencing analysis of human bone marrow derived mesenchymal stem cells is reported. The structure and stability of mucins is dependent on the presence of glycans in its structure. A thermosensitive hydrogel acquired from thermosensitive Poly (N-isopropyl acrylamide)-(PNIPAM) modified mucin and collagen is developed. The hydrogel demonstrates porous structure and mechanical strength. Newly formed bone tissue is observed at 8 weeks post-implantation in the hydrogel treated groups. The formation of blood vessels, nerves, and bone is observed with upregulation of angiopoietin (ANG), neurofilament heavy chain (NF-H), and osteoadherin (OSAD) or osteocalcin (OCN) respectively in rat calvarial defects. The outcome demonstrates that the thermosensitive injectable hydrogel accelerates repair and healing in calvarial bone defects making it a promising biodegradable biomaterial capable of regenerating bone by promoting angiogenesis and innervation.

Safety evaluation of enriched fraction from leaves of Dillenia indica L. in BALB/c mice.

The enriched fraction derived from Dillenia indica L. (Dilleniaceae), also known as elephant apple was subjected to acute and sub-acute toxicological study to document its safety issues for use as fumigant. The enriched fractions were orally administered to both sexes of BALB/c mice at doses of 200, 800 and 1600 mg/kg bw for acute toxicity, and 50 and 500 mg/kg bw for 14 days of sub-acute toxicity. Experimental results revealed that there were no signs of adverse toxicity, and mortality, with no significant treatment related effect in the percentage weight gain, daily feed and water intake, and haematological parameters. However, at higher dose in sub-acute toxicity study a patch of mild tubular injuries in kidney of female mice were observed as suggested by histopathological studies and mild abnormalities in levels of serum biochemical parameters. In general, it can be considered that the enriched fraction from D. indica leaves on oral feeding does not show any adverse effect on mice of both sexes. Hence, the highest doses 1600 mg/kg bw (acute) and 500 mg/kg bw (sub-acute) can be used as basal dose for the determination of no-observed-adverse-effect level (NOAEL) of enriched fraction from D. indica to calculate its safety margin.

Acute and sub-acute toxicity evaluation of dihydro-p-coumaric acid isolated from leaves of Tithonia diversifolia Hemsl. A. Gray in BALB/c mice.

In present study, the acute and sub-acute toxicities of Dihydro-p-coumaric acid isolated from the leaves of Tithonia diversifolia (Hemsl.) A. Gray was studied for safety issues in mammals. For acute toxicity tests, isolated compound was administered orally in both male and female BALB/c mice at the doses of 200, 800, and 1,600 mg/kg body weight for 7 days. In sub-acute toxicity study 50 and 500 mg/kg bw of the compound was orally administered for 14 days. Toxicity induced behavioural changes, haematological parameters, biochemical markers and histopathological sections were studied after Dihydro-p-coumaric acid administration. The vital organs like heart, kidney, uterus and testis revealed no adverse effects at doses of upto 1,600 mg/kg bw and 500 mg/kg bw. Slight hepatotoxicity was however demonstrated by ALT and AST assay but histopathological section did not concur as much. The study demonstrated insignificant difference in the percentage of feed intake, water intake, weight gain, haematological parameters and histopathological changes, with no toxicity signs and mortality. Dihydro-p-coumaric acid can be regarded as safe in both acute and sub-acute toxicity assay in both sexes. This indicates Dihydro-p-coumaric acid as a viable alternative to synthetic pesticides.

Malaria parasite heme biosynthesis promotes and griseofulvin protects against cerebral malaria in mice.

Heme-biosynthetic pathway of malaria parasite is dispensable for asexual stages, but essential for mosquito and liver stages. Despite having backup mechanisms to acquire hemoglobin-heme, pathway intermediates and/or enzymes from the host, asexual parasites express heme pathway enzymes and synthesize heme. Here we show heme synthesized in asexual stages promotes cerebral pathogenesis by enhancing hemozoin formation. Hemozoin is a parasite molecule associated with inflammation, aberrant host-immune responses, disease severity and cerebral pathogenesis. The heme pathway knockout parasites synthesize less hemozoin, and mice infected with knockout parasites are protected from cerebral malaria and death due to anemia is delayed. Biosynthetic heme regulates food vacuole integrity and the food vacuoles from knockout parasites are compromised in pH, lipid unsaturation and proteins, essential for hemozoin formation. Targeting parasite heme synthesis by griseofulvin-a FDA-approved antifungal drug, prevents cerebral malaria in mice and provides an adjunct therapeutic option for cerebral and severe malaria.

Assessment of NS1 protein as an early diagnostic marker for Kyasanur forest disease virus.

BACKGROUND & OBJECTIVES: Due to the emergence of Kyasanur forest disease (KFD) virus to new regions in India, there is an urgent need to develop an early diagnostic system, which is cost-effective and can be efficiently used with minimum paraphernalia. The non-structural-1 (NS1) protein is known to be an early diagnostic marker for flaviviruses. Furthermore, NS1 antigen capture ELISA kits developed using bacterially expressed dengue NS1 protein are commercially available. METHODS: Based on the data available on dengue virus, West Nile virus and other flaviviruses, bacterially expressed Kyasanur forest disease virus (KFDV) NS1 protein and polyclonal serum raised against the NS1 protein in mice and rabbit were used to develop an antigen capture ELISA for early diagnosis of the virus. The feasibility of this ELISA was further tested using in silico predictions. RESULTS: KFDV NS1 gene was cloned, expressed and confirmed by SDS-PAGE and western blotting. An antigen detection ELISA was standardized and sensitivity and specificity was tested with other flaviviruses. KFDV acute phase 43 samples were tested and only two were found to be positive for KFDV NS1 antigen. Superimposition of KFDV NS1 and TBEV NS1 revealed a root mean square distance (RMSD) of ~0.79 Å covering 1220 backbone atoms. This implies that the structures are very similar in terms of 3D fold. The identity of amino acid composition between these proteins was 73.4% and similarity was 92.9%, as revealed from the pairwise comparison. INTERPRETATION & CONCLUSION: The study points out that the half-life, expression and secretion levels of KFDV NS1 protein are not sufficient enough for its use as early diagnostic marker. The protein may have to be expressed in eukaryotic host to counter the lack of glycosylation in bacterial plasmid based expression of proteins. Hence, bacterially expressed KFDV NS1 protein may not be an ideal early diagnostic marker for the virus.

Clinical, pathological, and molecular investigation of Mycoplasma pulmonis-induced murine respiratory mycoplasmosis in a rat (Rattus norvegicus) colony.

AIM: Mycoplasma pulmonis (MP) remains potentially important rodent pathogen causing murine respiratory mycoplasmosis (MRM) which may go undiagnosed due to its asymptomatic nature. In the present study, we carried out clinical, pathological, and molecular investigations of MP-induced MRM in a rat colony. MATERIALS AND METHODS: Two female Wistar rats were observed to be diseased in animal facility of NISER, Bhubaneswar, and were kept in isolation for further investigation. Both the animals were found to be positive for MP after serological and molecular tests. Thereafter, whole rat colony comprising of 36 animals was segregated based on clinical symptoms and further sampled for histopathological, serological, and molecular investigations. Tracheal washing and infected lung tissue were collected during necropsy examination for DNA extraction. Molecular diagnosis was done by polymerase chain reaction (PCR) assay using species-specific primers. RESULT: Classical symptoms of MP-associated respiratory tract infection were observed in only 2 of 36 infected animals, and most of the animals were found asymptomatic to the disease; however, all the animals were found to be carrier after necropsy and PCR assay. Gross and histopathological finding suggested severe congestion of the lungs along with suppurative and necrotizing pneumonia. The disease is confirmed by molecular diagnosis using species-specific primers in PCR assay. CONCLUSION: MRM may go undiagnosed due to asymptomatic nature. Detailed study of clinical symptoms, pathology, serology, and PCR-based molecular approach may aid in health monitoring and detection of MRM in a rodent colony reared for experimental purpose.

Distinct functional modes of SUMOylation for retinoid X receptor alpha.

The present study investigated human retinoid X receptor alpha (hRXRα) as a substrate for modification with small ubiquitin like modifier (SUMO) and how members of the protein inhibitor of activated STAT (PIAS) family may impact upon this process. In agreement with a previous study, we validate Ubc9 to facilitate SUMOylation of hRXRα at lysine 108 but note this modification to occur for all isoforms rather than specifically with SUMO1 and to preferentially occur with the unliganded form of hRXRα. SUMOylation of hRXRα is significantly enhanced through PIAS4-mediated activity with lysine 245 identified as a specific SUMO2 acceptor site modified in a PIAS4-dependent fashion. While individual mutations at lysine 108 or 245 modestly increase receptor activity, the combined loss of SUMOylation at both sites significantly potentiates the transcriptional responsiveness of hRXRα suggesting both sites may cooperate in a DNA element-dependent context. Our findings highlight combinatorial effects of SUMOylation may regulate RXRα-directed signalling in a gene-specific fashion.

Sentrin/SUMO specific proteases as novel tissue-selective modulators of vitamin D receptor-mediated signaling.

Vitamin D receptor (VDR) is a substrate for modification with small ubiquitin-like modifier (SUMO). To further assess the role of reversible SUMOylation within the vitamin D hormonal response, we evaluated the effects of sentrin/SUMO-specific proteases (SENPs) that can function to remove small ubiquitin-like modifier (SUMO) from target proteins upon the activities of VDR and related receptors. We report that SENP1 and SENP2 strikingly potentiate ligand-mediated transactivation of VDR and also its heterodimeric partner, retinoid X receptor (RXRα) with depletion of cellular SENP1 significantly diminishing the hormonal responsiveness of the endogenous vitamin D target gene CYP24A1. We find that SENP-directed modulation of VDR activity is cell line-dependent, achieving potent modulatory effects in Caco-2 and HEK-293 cells, while in MCF-7 cells the vitamin D signal is unaffected by any tested SENP. In support of their function as novel modulators of the vitamin D hormonal pathway we demonstrate that both SENP1 and SENP2 can interact with VDR and reverse its modification with SUMO2. In a preliminary analysis we identify lysine 91, a residue known to be critical for formation and DNA binding of the VDR-RXR heterodimer, as a minor SUMO acceptor site within VDR. In combination, our results support a repressor function for SUMOylation of VDR and reveal SENPs as a novel class of VDR/RXR co-regulatory protein that significantly modulate the vitamin D response and which could also have important impact upon the functionality of both RXR-containing homo and heterodimers.

Detection of antibodies specific for foot-and-mouth disease virus infection using indirect ELISA based on recombinant nonstructural protein 2B.

Foot-and-mouth disease (FMD) is a highly contagious viral disease of transboundary importance. In India, since the launch of the FMD control programme, there has been a substantial increase in the vaccinated bovine population. In this scenario, there is a need for additional locally developed non-structural protein (NSP)-based immnoassays for efficient identification of FMD virus (FMDV)-infected animals in the vaccinated population. The 2B NSP of FMDV, lacking the transmembrane domain (Δ2B), was expressed successfully in a prokaryotic system, and an indirect ELISA (I-ELISA) was developed and validated in this study. The diagnostic sensitivity and specificity of the Δ2B I-ELISA were found to be 95.3 % and 94.6 %, respectively. In experimentally infected cattle, the assay could consistently detect Δ2B-NSP-specific antibodies from 10 to approximately 400 days postinfection. The assay was further validated with bovine serum samples collected randomly from different parts of the country. The performance of the Δ2B I-ELISA was compared with the in-house r3AB3 I-ELISA, and the overall concordance in test results was found to be 86.49 %. The Δ2B I-ELISA could be useful as a screening or confirmatory assay in the surveillance of FMD irrespective of vaccination.

PIAS4 represses vitamin D receptor-mediated signaling and acts as an E3-SUMO ligase towards vitamin D receptor.

The present study investigated the potential for members of the protein inhibitors of activated STAT (PIAS) family to function as co-regulators of the vitamin D signal pathway. Among the PIAS proteins evaluated, we establish PIAS4 as a potent inhibitor of the transcriptional responses of the CYP3A4 and CYP24A1 target genes to the active hormonal form of vitamin D, a repression that was observed to be dependent upon an intact SUMO-ligase function of PIAS4. We report that PIAS4 represents a direct binding partner for vitamin D receptor (VDR) and also facilitates its modification with SUMO2, a process that preferentially occurs on the apo-form of VDR and which is reversed upon binding of ligand. Our results implicate PIAS4 and the process of SUMOylation as important modulators of VDR-mediated signaling which may both represent flexible mechanistic components as to how vitamin D achieves its pleiotropic effects.