Genetic Characterisation and Local Genotypes of Canine Parvovirus Strains Collected from Pet Dogs in Central and Eastern China During 2018-2019.

INTRODUCTION: Canine parvovirus type-2 (CPV-2) causes acute infectious diseases in puppies, which show high morbidity and mortality. Better effect of vaccination against these diseases could be achieved with deeper knowledge of CPV-2 genotype dissemination and mutation history. This study investigated CPV-2-positive samples collected recently over a wide region of China. MATERIAL AND METHODS: A total of 118 faecal samples from dogs identified as CPV-positive were collected from veterinary clinics in central and eastern China. Overall, 16 strains collected from Anhui, 29 from Henan, and 16 from Zhejiang Province were sequenced to determine the genotypic composition of CPV-2 and mutational complexity of CPV-VP2. RESULTS: The CPV-2a, CPV-2b, and CPV-2c genotypes were detected in Anhui and Henan Provinces, while CPV-2c alone was detected in Zhejiang Province. Sequence analysis of all strains showed 98.5%-99.8%, 98.3%-99.9%, and 98.7%-99.8% identity among the 16 Anhui, 29 Henan, and 16 Zhejiang strains, respectively. Strains collected from Anhui and Henan Provinces showed lower identity (97.0%), suggesting greater genetic divergence in central China. The mutation rates of Henan and Anhui strains were lower than that of Zhejiang strains. Major amino acid mutations occurred at sites 5, 370, 426, and 440. Epitope and entropy analyses implied these sites' likely conformance to the principles of mutation tendency, complexity, and diversity. CONCLUSION: The findings for the evolutionary structure of CPV-2 strains collected from three provinces in central and eastern China advance trend monitoring of the genetic variation in canine parvovirus and point to its implications in the development of novel vaccines.

Inhibition of MALT1 paracaspase activity improves lesion recovery following spinal cord injury.

Spinal cord injury (SCI) is a devastating traumatic injury that causes persistent, severe motor and sensory dysfunction. Immune responses are involved in functional recovery after SCI. Mucosa-associated lymphoid tissue lymphoma translocation 1 (MALT1) has been shown to regulate the survival and differentiation of immune cells and to play a critical role in many diseases, but its function in lesion recovery after SCI remains unclear. In this paper, we generated KI (knock in) mice with a point mutation (C472G) in the active center of MALT1 and found that the KI mice exhibited improved functional recovery after SCI. Fewer macrophages were recruited to the injury site in KI mice and these macrophages differentiated into anti-inflammatory macrophages. Moreover, macrophages from KI mice exhibited reduced phosphorylation of p65, which in turn resulted in decreased SOCS3 expression and increased pSTAT6 levels. Similar results were obtained upon inhibition of MALT1 paracaspase with the small molecule inhibitor "MI-2" or the more specific inhibitor "MLT-827". In patients with SCI, peripheral blood mononuclear cells (PBMC) displayed increased MALT1 paracaspase. Human macrophages showed reduced pro-inflammatory and increased anti-inflammatory characteristics following the inhibition of MALT1 paracaspase. These findings suggest that inhibition of MALT1 paracaspase activity in the clinic may improve lesion recovery in subjects with SCI.

Glutaminolysis Mediated by MALT1 Protease Activity Facilitates PD-L1 Expression on ABC-DLBCL Cells and Contributes to Their Immune Evasion.

Previous studies have demonstrated that programmed death-1 ligand 1 (PD-L1) expressed in an aggressive activated B-cell (ABC)/non-germinal center B cell-like (GCB) subtype of diffuse large B-cell lymphoma (DLBCL) is associated with inhibition of the tumor-associated T cell response. However, the molecular mechanism underlying PD-L1 expression in ABC-DLBCL remains unclear. Here, we report that MALT1 protease activity is required for ABC-DLBCL cells to evade cytotoxity of Vγ9Vδ2 T lymphocytes by generating substantial PD-L1+ ABC-DLBCL cells. While, NF-κB was dispensable for the PD-L1 expression induced by MALT1 protease activity in ABC-DLBCL cells. Furthermore, we showed that GLS1 expression was profoundly reduced by MALT1 protease activity inhibition, which resulted in insufficiency of glutaminolysis-derived mitochondrial bioenergetics. Activation of the PD-L1 transcription factor STAT3, which was strongly suppressed by glutaminolysis blockade, was rescued in a TCA (tricarboxylic acid) cycle-dependent manner by glutamate addition. Collectively, MALT1 protease activity coupled with glutaminolysis-derived mitochondrial bioenergetics plays an essential role in PD-L1 expression on ABC-DLBCL cells under immunosurveillance stress. Thus, our research sheds light on a mechanism underlying PD-L1 expression and highlights a potential therapeutic target to vanquish immune evasion by ABC-DLBCL cells.

Effects of different selenium levels on gene expression of a subset of selenoproteins and antioxidative capacity in mice.

This study aimed to evaluate how excess selenium induces oxidative stress by determining antioxidant enzyme activity and changes in expression of selected selenoproteins in mice. BALB/c mice (n = 20 per group) were fed a diet containing 0.045 (Se-marginal), 0.1 (Se-adequate), 0.4 (Se-supernutrition), or 0.8 (Se-excess) mg Se/kg. Gene expression was quantified in RNA samples extracted from the liver, kidney, and testis by real-time quantitative reverse transcription-polymerase chain reaction. We found that glutathione peroxidase (GPx) and catalase activities decreased in livers of mice fed the marginal or excess dose of Se as compared to those in the Se-adequate group. Additionally, superoxide dismutase and glutathione reductase activities were significantly reduced only in mice fed the excess Se diet, compared to animals on the adequate Se diet. Se-supernutrition had no effect on hepatic mRNA levels of GPx isoforms 1 and 4 (GPx1 and GPx4), down-regulated GPx isoform 3 (GPx3), and upregulated selenoprotein W (SelW) mRNA expression. The excess Se diet led to decreased hepatic mRNA levels of GPx1, GPx3 and GPx4 but no change in testicular mRNA levels of GPx1, GPx3 or SelW. Dietary Se had no effect on testicular mRNA levels of GPx4. Thus, our results suggest that Se exposure can reduce hepatic antioxidant capacity and cause liver dysfunction. Dietary Se was found to differentially regulate mRNA levels of the GPx family or SelW, depending on exposure. Therefore, these genes may play a role in the toxicity associated with Se.

Effect of fragile histidine triad gene transduction on proliferation and apoptosis of human hepatocellular carcinoma cells.

AIM: To evaluate the inhibitory effects of human fragile histidine triad (FHIT) gene on cell proliferation and apoptosis in human hepatocellular carcinoma line Hep3B in vitro. METHODS: A recombinant pcDNA3.1 (+)/FHIT including the functional region of FHIT gene was constructed and transferred into human hepatocellular carcinoma cells in vitro. mRNA and protein expression of the FHIT gene in the transfected cells was detected by RT-PCR and Western blot, respectively. The effect of FHIT on proliferation was detected by MTT assay. Changes in cell cycle and apoptosis were assayed by flow cytometry. Five mice received subcutaneous transplantation of Hep3B-FHIT; 5 mice received subcutaneous transplantation of normal Hep3B and Hep3B-C as controls. The body weight of nude mice and tumor growth were measured. RESULTS: RT-PCR and Western blot analysis showed that the expression level of FHIT-mRNA and FHIT protein was higher in Hep3B cells after infection with pcDNA3.1 (+)/FHIT. The growth of Hep3B cells treated with pcDNA3.1 (+)/FHIT was significantly inhibited. The pcDNA3.1 (+)/FHIT-transfected Hep3B cells showed a significantly higher cell rate at G(0)-G(1) phase and increased apoptosis in comparison with controls (P < 0.05). The growth of transplanted tumor was inhibited markedly by FHIT. Tumors arising from the Hep3B-FHIT cells occurred much later than those arising from the Hep3B and Hep3B-C cells. The growth of Hep3B-FHIT cells was slow and the tumor volume was low. CONCLUSION: Transduction of FHIT gene inhibits the growth of human hepatocellular carcinoma cells and induces cell apoptosis in vivo and in vitro.