[Research progress of human coronaviruses and associated eye diseases].

Coronaviruses are RNA viruses. We should be alerted from the outbreak of the severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003, the discovery of the human coronavirus NL63 (HCoV-NL63) in 2004 and the pneumonia outbreak caused by the novel coronavirus in 2019 (2019-nCoV). Coronaviruses can adhere to mucous membranes of the eye, nose, mouth, respiratory tract and digestive tract through various media, which leads to inflammatory reaction, pulmonary fibrosis, kidney failure and death in severe cases. As an exposed organ, the eye can also be infected. With the progress of molecular technology and the in-depth research of coronaviruses, there have been seven known coronaviruses that can infect humans, among which HCoV-NL63, SARS-CoV and 2019-nCoV can cause eye diseases. This article summarizes and analyzes the latest research results at home and abroad concerning the structural characteristics, transmission routes, ocular pathogenic characteristics and treatment of HCoV-NL63, SARS-CoV and 2019-nCoV, in order to provide reference for clinical diagnosis and treatment. (Chin J Ophthalmol, 2021, 57: 871-875).

Phylogeography and origin of Chinese domestic chicken.

The loss of local chicken breeds as result of replacement with cosmopolitan breeds indicates the need for conservation measures to protect the future of local genetic stocks. The aim of this study is to describe the patterns of polymorphism of the hypervariable control region of mitochondrial DNA (HVR1) in domestic chicken in China's Jiangxi province to investigate genetic diversity, genetic structure and phylo-dynamics. To this end, we sequenced the mtDNA HVR1 in 231 chickens including 22 individuals which belonged to previously published sequences. A neighbor-joining tree revealed that these samples clustered into five lineages (Lineages A, B, C, E and G). The highest haplotype diversity and nucleotide diversity were both found in Anyi tile-liked gray breed. We estimated that the most recent common ancestor of the local chicken existed approximately 16 million years ago. The mismatch distribution analysis showed two major peaks at positions 4 and 9, while the neutrality test (Tajima's D = -2.19, p < 0.05) and Fu's F-statistics (-8.59, p < 0.05) revealed a significant departure from the neutrality assumption. These results support the idea that domestication of chickens facilitated population increases. Results of a global AMOVA indicated that there was no obvious geographic structure among the local chicken breeds analyzed in this study. The data obtained in this study will assist future conservation management of local breeds and also reveals intriguing implications for the history of human population movements and commerce.

Pharmacological reduction of NEFA restores the efficacy of incretin-based therapies through GLP-1 receptor signalling in the beta cell in mouse models of diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes mellitus is associated with reduced incretin effects. Although previous studies have shown that hyperglycaemia contributes to impaired incretin responses in beta cells, it is largely unknown how hyperlipidaemia, another feature of type 2 diabetes, contributes to impaired glucagon-like peptide 1 (GLP-1) response. Here, we investigated the effects of NEFA on incretin receptor signalling and examined the glucose-lowering efficacy of incretin-based drugs in combination with the lipid-lowering agent bezafibrate. METHODS: We used db/db mice to examine the in vivo efficacy of the treatment. Beta cell lines and mouse islets were used to examine GLP-1 and glucose-dependent insulinotropic peptide receptor signalling. RESULTS: Palmitate treatment decreased Glp1r expression in rodent insulinoma cell lines and isolated islets. This was associated with impairment of the following: GLP-1-stimulated cAMP production, phosphorylation of cAMP-responsive elements binding protein (CREB) and insulin secretion. In insulinoma cell lines, the expression of exogenous Glp1r restored cAMP production and the phosphorylation of CREB. Treatment with bezafibrate in combination with des-fluoro-sitagliptin or exendin-4 led to more robust glycaemic control, associated with improved islet morphology and beta cell mass in db/db mice. CONCLUSIONS/INTERPRETATION: Elevated NEFA contributes to impaired responsiveness to GLP-1, partially through downregulation of GLP-1 receptor signalling. Improvements in lipid control in mouse models of obesity and diabetes increase the efficacy of incretin-based therapy.