Putative roles as oncogene or tumour suppressor of the Mid-clustered microRNAs in Gallid alphaherpesvirus 2 (GaHV2) induced Marek's disease lymphomagenesis.

In the last decade, numerous microRNAs (miRNAs) have been identified in diverse virus families, particularly in herpesviruses. Gallid alphaherpesvirus 2 (GaHV2) is a representative oncogenic alphaherpesvirus that induces rapid-onset T-cell lymphomas in its natural hosts, namely Marek's disease (MD). In the GaHV2 genome there are 26 mature miRNAs derived from 14 precursors assembled into three clusters, namely the Meq-cluster, Mid-cluster and LAT-cluster. Several GaHV2 miRNAs, especially those in the Meq-cluster (e.g. miR-M4-5p), have been demonstrated to be critical in MD pathogenesis and/or tumorigenesis. Interestingly the downstream Mid-cluster is regulated and transcribed by the same promoter as the Meq-cluster in the latent phase of the infection, but the role of these Mid-clustered miRNAs in GaHV2 biology remains unclear. We have generated the deletion mutants of the Mid-cluster and of its associated individual miRNAs in GX0101 virus, a very virulent GaHV2 strain, and demonstrated that the Mid-clustered miRNAs are not essential for virus replication. Using GaHV2-infected chickens as an animal model, we found that, compared with parental GX0101 virus, the individual deletion of miR-M31 decreased the mortality and gross tumour incidence of infected chickens while the deletion individually of miR-M1 or miR-M11 unexpectedly increased viral pathogenicity or oncogenicity, similarly to the deletion of the entire Mid-cluster region. More importantly, our data further confirm that miR-M11-5p, the miR-M11-derived mature miRNA, targets the viral oncogene meq and suppresses its expression in GaHV2 infection. We report here that members of the Mid-clustered miRNAs, miR-M31-3p and miR-M11-5p, potentially act either as oncogene or tumour suppressor in MD lymphomagenesis.

Molecular Epidemiology and Pathogenic Characterization of Novel Chicken Infectious Anemia Viruses in Henan Province of China.

Chicken infectious anemia (CIA) is an immunosuppressive disease caused by the chicken infectious anemia virus (CIAV) resulting in heavy economic losses once an outbreak is established. This study conducted a systematic analysis of the epidemiology and pathology of CIA in Henan province, China. A total of 437 clinical tissue samples and 120 poultry disease-related live attenuated vaccines were collected during 2017-2020; of which 45 were positive for CIAV nucleic acid, with a positive rate of 8.08%. Our results showed that genome sequence similarity among a total of 12 CIAV isolates was high, and ranged from 97.1 to 99.3%, and their similarity to the vaccine strains Cux-1 and Del-Ros ranged from 97.8 to 98.6%. However, There were mutations in the locus of the major capsid proteins VP1, VP2, and VP3 among all isolates. The subsequent sequence analysis indicated that the isolates of HN-4 and HN-8 showed genetic recombination and follow up animal experiments revealed that HN-4 might be a pathogenic strain. Our results reveal that both field infection and non-CIAV vaccines contamination promote the epidemiology of CIAV in China and some dominant epidemic viruses have undergone recombination and evolution. This study provides important information to help with the prevention and control of CIAV in the poultry industry.

SNAP-25(1-180) enhances insulin secretion by blocking Kv2.1 channels in rat pancreatic islet beta-cells.

Voltage-gated outward K(+) currents from pancreatic islet beta-cells are known to repolarize the action potential during a glucose stimulus, and consequently to modulate Ca(2+) entry and insulin secretion. The voltage gated K(+) (Kv) channel, Kv2.1, which is expressed in rat islet beta-cells, mediates over 60% of the Kv outward K(+) currents. A novel peptidyl inhibitor of Kv2.1/Kv2.2 channels, guangxitoxin (GxTX)-1, has been shown to enhance glucose-stimulated insulin secretion. Here, we show that SNAP-25(1-180) (S180), an N-terminal SNAP-25 domain, but not SNAP-25(1-206) (S206), inhibits Kv current and enhances glucose-dependent insulin secretion from rat pancreatic islet beta-cells, and furthermore, this enhancement was induced by the blockade of the Kv2.1 current. This study indicates that the Kv2.1 channel is a potential target for novel therapeutic agent design for the treatment of type 2 diabetes. This target may possess advantages over currently-used therapies, which modulate insulin secretion in a glucose-independent manner.

An exploratory study of the association between KCNB1 rs1051295 and type 2 diabetes and its related traits in Chinese Han population.

Since the KCNB1 encoding Kv2.1 channel accounts for the majority of Kv currents modulating insulin secretion by pancreatic islet beta-cells, we postulated that KCNB1 is a plausible candidate gene for genetic variation contributing to the variable compensatory secretory function of beta-cells in type-2 diabetes (T2D). We conducted two studies, a case-control study and a cross-section study, to investigate the association of common single-nucleotide polymorphisms (SNPs) in KCNB1 with T2D and its linking traits. In the case-control study, we first examined the association of 20 tag SNPs of KCNB1 with T2D in a population with 226 T2D patients and non-diabetic subjects (screening study). We then identified the association in an enlarged population of 412 T2D patients and non-diabetic subjects (replication study). In the cross-sectional study, we investigated the linkage between the candidate SNP rs1051295 and T2D by comparing beta-cell function and insulin sensitivity among rs1051295 genotypes in a general population of 1051 subjects at fasting and after glucose loading (oral glucose tolerance tests, OGTT) in 84 fasting glucose impaired subjects, and several T2D-related traits. We found that among the 19 available tag SNPs, only the KCNB1 rs1051295 was associated with T2D (P = 0.027), with the rs1051295 TT genotype associated with an increased risk of T2D compared with genotypes CC (P = 0.009). At fasting, rs1051295 genotype TT was associated with a 9.8% reduction in insulin sensitivity compared to CC (P = 0.008); along with increased plasma triglycerides (TG) levels (TT/CC: P = 0.046) and increased waist/hip (W/H) ratio (TT/CC: P = 0.013; TT/TC: P = 0.002). OGTT confirmed that genotype TT exhibited reduced insulin sensitivity by 16.3% (P = 0.030) compared with genotype TC+CC in a fasting glucose impaired population. The KCNB1 rs1051295 genotype TT in the Chinese Han population is associated with decreased insulin sensitivity and increased plasma TG and W/H ratio, which together contribute to an increased risk for T2D.

Lysosomal cysteine peptidase cathepsin L protects against cardiac hypertrophy through blocking AKT/GSK3beta signaling.

The lysosomal cysteine peptidase cathepsin L (CTSL) is an important lysosomal proteinase involved in a variety of cellular functions including intracellular protein turnover, epidermal homeostasis, and hair development. Deficiency of CTSL in mice results in a progressive dilated cardiomyopathy. In the present study, we tested the hypothesis that cardiac overexpression of human CTSL in the murine heart would protect against cardiac hypertrophy in vivo. The effects of constitutive human CTSL expression on cardiac hypertrophy were investigated using in vitro and in vivo models. Cardiac hypertrophy was produced by aortic banding (AB) in CTSL transgenic mice and control animals. The extent of cardiac hypertrophy was quantitated by two-dimensional and M-mode echocardiography as well as by molecular and pathological analyses of heart samples. Constitutive overexpression of human CTSL in the murine heart attenuated the hypertrophic response, markedly reduced apoptosis, and fibrosis. Cardiac function was also preserved in hearts with increased CTSL levels in response to hypertrophic stimuli. These beneficial effects were associated with attenuation of the Akt/GSK3beta signaling cascade. Our in vitro studies further confirmed that CTSL expression in cardiomyocytes blunts cardiac hypertrophy through blocking of Akt/GSK3beta signaling. The study indicates that CTSL improves cardiac function and inhibits cardiac hypertrophy, inflammation, and fibrosis through blocking Akt/GSK3beta signaling.

[Actions of Syn-1A on blocking the activation of K(ATP) channel induced by acidic pH].

AIM: To investigate the action and mechanism of Syn-1A in reversing the activation of K(ATP) channel induced by weak acidic pH. METHODS: The patches excised from Kir6.2/SUR2A expressing HEK-293 cells were used to establish inside-out configuration. To examine the actions of weak acidic pH in activation of the channel and the reverse action of Syn-1A on it, the inside-out patches were continuously perfused with the solution of pH from 7.4, 7.0, 6.8, 6.5 to 6.0 with or without Syn-1A. In vitro binding was employed to study the influence of different pH to the binding of Syn-1A to SUR2A subunit. RESULTS: Syn-1A blocked pH 6.5, 6.8 and 7.0 induced activation of the channel, and Syn-1A binding to SUR2A were increased by reducing pH from 7.4 to 6.0. CONCLUSION: Syn-1A would assert some inhibition of the KATP channels, which might temper the fluctuation of acidic pH-induced K(ATP) channel opening that could induce fatal re-entrant arrhythmias.