Rho family GTPases belong to the Ras GTPase superfamily and transduce intracellular signals known to regulate a variety of cellular processes, including cell polarity, morphogenesis, migration, apoptosis, vesicle trafficking, viral transport and cellular transformation. The three best-characterized Rho family members are Cdc42, RhoA and Rac1. Cdc42 regulates endocytosis, the transport between the endoplasmic reticulum and Golgi apparatus, post-Golgi transport and exocytosis. Cdc42 influences trafficking through interaction with Wiskott-Aldrich syndrome protein (N-WASP) and the Arp2/3 complex, leading to changes in actin dynamics. Rac1 mediates endocytic and exocytic vesicle trafficking by interaction with its effectors, PI3kinase, synaptojanin 2, IQGAP1 and phospholipase D1. RhoA participates in the regulation of endocytosis through controlling its downstream target, Rho kinase. Interestingly, these GTPases play important roles at different stages of viral protein and genome transport in infected host cells. Importantly, dysregulation of Cdc42, Rac1 and RhoA leads to numerous disorders, including malignant transformation. In some cases, hyperactivation of Rho GTPases is required for cellular transformation. In this article, we review a number of findings related to Rho GTPase function in intracellular transport and cellular transformation.

Effects of green macroalgae 55% ethanolic extract Enteromorpha prolifera through an ultrafiltration membrane of 3 kDa (EPE3k) on antidiabetic activity, gut microbiota, and regulation mechanism were investigated in high-fat/high-sucrose diet and streptozocin-induced diabetic mice. The structural characterizations of its major compounds in EPE3k were determined by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry. Furthermore, the intestinal microflora modulation in diabetic mice was also investigated with high-throughput 16S rRNA gene sequencing. The proposed presence of polyphenols in EPE3k was confirmed. EPE3k could significantly decrease the fasting blood glucose and improve fasting glucose tolerance. The hypoglycemic effect of EPE3k was via activation of phosphatidylinositol 3-kinase and suppression of c-Jun N-terminal kinase in liver. EPE3k treatment significantly increased the relative abundance of Akkermansia and decreased the proportion of Alistipes and Turicibacter. The above results indicated that EPE3k could be provided as a new potential therapy for the treatment of type 2 diabetic mellitus.

: Non-alcoholic fatty liver disease (NAFLD) is a major public health problem in many countries. In this study, the ability of Grifola frondosa heteropolysaccharide (GFP) to ameliorate NAFLD was investigated in rats fed a high-fat diet (HFD). The molecular mechanisms modulating the expression of specific gene members related to lipid synthesis and conversion, cholesterol metabolism, and inflammation pathways were determined. The components of the intestinal microflora in rats were analyzed by high-throughput next-generation 16S rRNA gene sequencing. Supplementation with GFP significantly increased the proportions of Allobaculum, Bacteroides, and Bifidobacterium and decreased the proportions of Acetatifactor, Alistipes, Flavonifractor, Paraprevotella, and Oscillibacter. In addition, Alistipes, Flavonifractor, and Oscillibacter were shown to be significant cecal microbiota according to the Spearman’s correlation test between the gut microbiota and biomedical assays (|r| > 0.7). Histological analysis and biomedical assays showed that GFP treatments could significantly protect against NAFLD. In addition, Alistipes, Flavonifractor, and Oscillibacter may play vital roles in the prevention of NAFLD. These results suggest that GFP could be used as a functional material to regulate the gut microbiota of NAFLD individuals.

The aim of this work was to clarify the molecular mechanism underlying the fatty degeneration of livers infected with Muscovy duck reovirus (MDRV), which produces obvious white necrotic foci in the liver. Transcriptome data for MDRV-infected Muscovy duck livers and control livers were sequenced, assembled, and annotated with Illumina^® HiSeq 2000. The differentially expressed genes were screened and their functions were analysed. We also determined and confirmed the molecular mechanism of the hepatic fat metabolism disorder caused by MDRV infection. The expression of 4190 genes was higher in the infected livers than in the control livers, and the expression of 1113 genes was reduced. A Gene Ontology analysis showed that these genes were involved in 48 biological functions, and were significantly enriched in 237 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The free fatty acid content was significantly higher in the livers of infected Muscovy ducks than in the control livers (P < 0.01). The KEGG analysis showed that MDRV infection inhibited the cholesterol efflux from hepatic cells and reduced the expression of key enzymes involved in fatty acid degradation (scavenger receptor class b type 1, ABCG8, and APOA4), leading to the accumulation of fatty acids and cholesterol in the liver cells. In this study, we have identified the genes differentially expressed in livers infected by MDRV, from which we inferred the genes associated with lipodystrophia, and elucidated the molecular mechanism of the hepatic steatosis induced by MDRV. Abbreviations: ABC: ATP binding cassette transport; ACADVL: acyl-CoA dehydrogenase, very long chain; ACAT: mitochondrial-like acetyl-CoA acetyltransferase A; ACAT2: acetyl-CoA acyltransferase 2; ACNAT2: acyl-coenzyme A amino acid N-acyltransferase 2-like; ACOT1: acyl-CoA thioesterase 1; ACOT7: acyl-CoA thioesterase 7; ACOX1: acyl-CoA oxidase 1, palmitoyl; ACSBG2: acyl-CoA synthetase bubblegum family member 2; ACSL1: acyl-CoA synthetase long-chain family member 1; ADH1: alcohol dehydrogenase 1; APOA4: apolipoprotein A-IV; ARV: avian reovirus; cDNA: complementary deoxyribonucleic acid; COG: Clusters of Orthologous Groups; DEG: differentially expressed gene; DGAT: diacylgycerol acyltransferase; DNA: deoxyribonucleic acid; ECI2: enoyl-CoA delta isomerase 2; EHHADH: enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase; FDR: false discovery rate; GCDH: Pseudopodoces humilis glutaryl-CoA dehydrogenase; GO: Gene Ontology; HADHA: hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), alpha subunit; I-FABP: intestinal fatty acid binding protein; KEGG: Kyoto Encyclopedia of Genes and Genomes; L-FABP: liver fatty acid binding protein; MDRV: Muscovy duck reovirus; MOI: multiplicity of infection; NPC1L1: Niemann-Pick C1-like 1; qPCR: real-time quantitative polymerase chain reaction; RNA: ribonucleic acid; RNase: ribonuclease; RNA-seq: RNA sequencing technology; RPKM: reads per kilobase per million mapped reads; SR-B1: scavenger receptor class b type 1.