Molecular cloning, polymorphism, and expression analysis of the LKB1/STK11 gene and its association with non-specific digestive disorder in rabbits

Genome-wide association studies for diarrhoea outcomes identified genomic regions affecting resistance to a severe enteropathy in suckling rabbits

Selection and breeding strategies to improve resistance to enteropathies are essential to reaching the sustainability of the rabbit production systems. However, disease heterogeneity (having only as major visible symptom diarrhoea) and low disease heritability are two barriers for the implementation of these strategies. Diarrhoea condition can affect rabbits at different life stages, starting from the suckling period, with large negative economic impacts. In this study, from a commercial population of suckling rabbits (derived from 133 litters) that experienced an outbreak of enteropathy, we first selected a few animals that died with severe symptoms of diarrhoea and characterized their microbiota, using 16S rRNA gene sequencing data. Clostridium genus was consistently present in all affected specimens. In addition, with the aim to identify genetic markers in the rabbit genome that could be used as selection tools, we performed genome-wide association studies for symptoms of diarrhoea in the same commercial rabbit population. These studies were also complemented with FST analyses between the same groups of rabbits. A total of 332 suckling rabbits (151 with severe symptoms of diarrhoea, 42 with mild symptoms and 129 without any symptoms till the weaning period), derived from 45 different litters (a subset of the 133 litters) were genotyped with the Affymetrix Axiom OrcunSNP Array. In both genomic approaches, rabbits within litters were paired to constitute two groups (susceptible and resistant, including the mildly affected in one or the other group) and run case and control genome-wide association analyses. Genomic heritability estimated in the designed experimental structure integrated in a commercial breeding scheme was 0.19-0.21 (s.e. 0.09-0.10). A total of eight genomic regions on rabbit chromosome 2 (OCU2), OCU3, OCU7, OCU12, OCU13, OCU16 and in an unassembled scaffold had significant single nucleotide polymorphisms (SNPs) and/or markers that trespassed the FST percentile distribution. Among these regions, three main peaks of SNPs were identified on OCU12, OCU13 and OCU16. The QTL region on OCU13 encompasses several genes that encode members of a family of immunoglobulin Fc receptors (FCER1G, FCRLA, FCRLB and FCGR2A) involved in the immune innate system, which might be important candidate genes for this pathogenic condition. The results obtained in this study demonstrated that resistance to an enteropathy occurring in suckling rabbits is in part genetically determined and can be dissected at the genomic level, providing DNA markers that could be used in breeding programmes to increase resistance to enteropathies in meat rabbits.

MicroRNA-106a-5p promotes the proliferation, autophagy and migration of lung adenocarcinoma cells by targeting LKB1/AMPK

It has previously been reported that lung cancer has the highest morbidity and mortality rate worldwide; however, the pathogenesis underlying lung cancer has not been fully elucidated. The aim of the present was primarily to assess the influence of microRNA (miR)-106a-5p on the biological behaviors of lung cancer cells. In the present study, bioinformatics analysis was used to analyze the expression characteristics of miR-106a-5p and its relationship with the prognosis of patients with lung adenocarcinoma (LUAD) in The Cancer Genome Atlas. A dual luciferase reporter assay was performed to verify the binding of miR-106a-5p and liver kinase B1 (LKB1). The Cell Counting Kit-8, colony formation and Transwell assays were utilized to detect cell viability, proliferation and migration, respectively. Protein and RNA expression levels were examined by western blotting and reverse transcription-quantitative PCR analysis, respectively. It was observed that miR-106a-5p was highly expressed in LUAD and associated with poor prognosis. miR-106a-5p promoted the proliferation and migration of LUAD cells, and inhibited autophagy. By contrast, LKB1 inhibited cell proliferation and migration, promoted autophagy and blocked the cancer-promoting effects of miR-106a-5p. Overexpression of miR-106a-5p inhibited the phosphorylation of AMP-activated protein kinase (AMPK) and tuberin (TSC2), and promoted the phosphorylation of mTOR. By contrast, overexpression of LKB1 blocked the promotion of mTOR phosphorylation, and the inhibition of AMPK and TSC2 phosphorylation caused by miR-106a-5p. In summary, the results of the present study indicated that miR-106a-5p regulated the phosphorylation of the AMPK pathway by targeting LKB1, and was involved in the proliferation, migration and autophagy of LUAD cells.

Effect of Liver Kinase B1 on Osteogenic/Adipogenic Differentiation of Bone Marrow Mesenchymal Stem Cells in High Glucose Environment

Bone marrow mesenchymal stem cells (BMSCs) present reduced proliferation under high glucose condition. Liver kinase B1 (LKB1) can maintain the homeostasis of hematopoietic stem cells. However, whether LKB1 regulates BMSCs osteogenic/adipogenic differentiation under high glucose is unclear. Rat BMSCs were isolated and separated into control group, high glucose group, and LKB1 group (BMSCs were transfected with pc-DNA 3.1-LKB1 plasmid under high glucose condition) followed by analysis of LKB1 expression by Real time PCR and Western blot, osteocalcin, type I collagen, RUNX2 and OPN mRNA level by real-time PCR, FABP4 and PPARγ2 level by western blot. In high glucose group, LKB1 expression was significantly decreased, with reduced expression of osteocalcin, type I collagen, RUNX2 and OPN mRNA and elevated FABP4 and PPARγ2 level compared to control group (P < 0.05). Transfection of LKB1 plasmid reduced LKB1 expression, upregulated osteocalcin, type I collagen, RUNX2 and OPN mRNA and downregulated FABP4 and PPARγ2. Compared with the high glucose group, there was a statistical difference (P <0.05). High glucose can inhibit LKB1 expression and BMSCs osteogenic differentiation, and promote adipogenic differentiation. Upregulating LKB1 expression can promote BMSCs osteogenic differentiation.

Genome-Wide SNPs and InDels Characteristics of Three Chinese Cattle Breeds

Simple Summary

Whole-genome resequencing is an important tool to reveal the in-depth genomic characteristics of a genome. Adaptability traits are key to the survival of the south Chinese zebu cattle. However, the potential genetic information behind these remarkable traits still remains uncertain and needs to be addressed. In the current study, we utilized a total of 15 local south Chinese cattle samples (Leiqiong (LQ), Wannan (WN), Wenshan (WS)) from one of our previous studies mapped to the old reference genome (Btau_5.0.1) and remapped them to the latest reference genome (ARS-UCD1.2) to explore potential single nucleotide polymorphisms (SNPs) and insertions-deletions (InDels) responsible for some important immune related traits. The present study emphasizes and illustrates the genetic diversity, extending our previous study. The InDel annotation show that WS cattle had more enriched genes associated with immune functions than the other two breeds. Our findings provide valuable resources for further investigation of the functions of SNP- and InDels-related genes and help to determine the molecular basis of adaptive mutations in Chinese zebu cattle.

Abstract

We report genome characterization of three native Chinese cattle breeds discovering ~34.3 M SNPs and ~3.8 M InDels using whole genome resequencing. On average, 10.4 M SNPs were shared amongst the three cattle breeds, whereas, 3.0 M, 4.9 M and 5.8 M were specific to LQ, WN and WS breeds, respectively. Gene ontology (GO)analysis revealed four immune response-related GO terms were over represented in all samples, while two immune signaling pathways were significantly over-represented in WS cattle. Altogether, we found immune related genes (PGLYRP2, ROMO1, FYB2, CD46, TSC1) in the three cattle breeds. Our study provides insights into the genetic basis of Chinese indicine adaptation to the tropic and subtropical environment, and provides a valuable resource for further investigations of genetic characteristics of the three breeds.