Paternal sleep deprivation induces metabolic perturbations in male offspring via altered LRP5 DNA methylation of pancreatic islets.

Diabetes and metabolic perturbation are global health challenges. Sleep insufficiency may trigger metabolic dysregulation leading to diabetes. However, the intergenerational transmission of this environmental information is not clearly understood. The research objective was to determine the possible effect of paternal sleep deprivation on the metabolic phenotype of the offspring and to investigate the underlying mechanism of epigenetic inheritance. Male offspring of sleep-deprived fathers exhibit glucose intolerance, insulin resistance, and impaired insulin secretion. In these SD-F1 offspring, a reduction in beta cell mass and proliferation of beta cells were observed. Mechanistically, in pancreatic islets of SD-F1 offspring, we identified alterations in DNA methylation at the promoter region of the LRP5 (LDL receptor related protein 5) gene, a coreceptor of Wnt signaling, resulting in downregulation of downstream effectors cyclin D1, cyclin D2, and Ctnnb1. Restoration of Lrp5 in the pancreas of SD-F1 male mice could improve impaired glucose tolerance and expression of cyclin D1, cyclin D2, and Ctnnb1. This study might significantly contribute to our understanding of the effects of sleeplessness on health and metabolic disease risk from the perspective of the heritable epigenome.

VR-10 polypeptide interacts with CD36 to induce cell apoptosis and autophagy in choroid-retinal endothelial cells: Identification of VR-10 as putative novel therapeutic agent for choroid neovascularization (CNV) treatment.

Choroid neovascularization (CNV) is important adverse pathological changes that contributes to the aggravation of hypoxic-ischemic eye diseases, and our preliminary work evidences that the thrombospondin-1 (TSP-1) synthetic polypeptide VR-10 may be the candidate therapeutic agent for the treatment of CNV, but its detailed effects and molecular mechanisms are not fully delineated. In this study, the CNV models in BN rats were established by using the laser photocoagulation method, which were further subjected to VR-10 peptide treatment. The RNA-seq and bioinformatics analysis suggested that VR-10 peptide significantly altered the expression patterns of genes in the rat ocular tissues, and the changed genes were especially enriched in the CD36-associated signal pathways. Next, by performing the Real-Time qPCR and Western Blot analysis, we expectedly found that VR-10 upregulated the anti-angiogenesis biomarker (PEDF) and downregulated pro-angiogenesis biomarkers (VEGF, HIF-1 and IL-17) in rat tissues. In addition, we evidenced that VR-10 downregulated CDK2, CDK4, CDK6, Cyclin D1 and Cyclin D2 to induce cell cycle arrest, upregulated cleaved Caspase-3, Bax and downregulated Bcl-2 to promote cell apoptosis, and increased LC3B-II/I ratio and facilitate p62 degradation to promote cell autophagy in RF/6A cells, which were all reversed by knocking down CD36. Moreover, VR-10 upregulated PEDF, and decreased the expression levels of VEGF, HIF-1 and IL-17 to block angiogenesis of RF/6A cells in a CD36-dependent manner. Taken together, VR-10 peptide interacts with its receptor CD36 to regulate the biological functions of RF/6A cells, and these data suggest that VR-10 peptide may be the putative therapeutic drug for the treatment of CNV in clinic.

Exosomal transfer of circ_0006174 contributes to the chemoresistance of doxorubicin in colorectal cancer by depending on the miR-1205/CCND2 axis

Exosomes are the mediators of intercellular signal transduction, and they have been involved in the carcinogenesis and chemoresistance of tumor cells. Herein, we intended to investigate whether circular RNA (circRNA) circ_0006174 can regulate chemoresistance of doxorubicin (DOX) in colorectal cancer via exosomes. Forty-one pairs of normal and CRC (DOX sensitive, n = 16; DOX resistant, n = 25) samples were collected. The resistant cell lines (LoVo/DOX and HCT116/DOX) were constructed by exposure of parental cell lines (LoVo and HCT116) to DOX. The detection of circ_0006174, microRNA-1205 (miR-1205), and cyclin D2 (CCND2) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8(CCK-8) was applied for determining the half of inhibitory concentration (IC50) of DOX and cell proliferation. The migration and invasion capacities were analyzed via transwell assay. Exosomes were extracted using ultracentrifugation. Protein levels were determined using western blot. Dual-luciferase reporter assay was used for affirming target interaction. In vivo experiment was performed by establishing xenograft models in mice. Circ_0006174 level was upregulated in DOX-resistant CRC tissues and cells. The downregulation of circ_0006174 inhibited DOX resistance, cell proliferation, migration, and invasion in DOX-resistant CRC cells. Interestingly, the abundant circ_0006174 was enriched in exosomes derived from DOX-resistant CRC cells. Furthermore, circ_0006174 could enhance DOX resistance via the exosomal intercellular transfer. Moreover, we validated the target relation of circ_0006174/miR-1205 or miR-1205/CCND2. The effect of exosomal circ_0006174 on DOX resistance was achieved by upregulating the miR-1205-mediated CCND2. In vivo, knockdown of circ_0006174 also enhanced tumor sensitivity to DOX by targeting miR-1205/CCND2 axis. (AU)

Exosomal transfer of circ_0006174 contributes to the chemoresistance of doxorubicin in colorectal cancer by depending on the miR-1205/CCND2 axis.

Exosomes are the mediators of intercellular signal transduction, and they have been involved in the carcinogenesis and chemoresistance of tumor cells. Herein, we intended to investigate whether circular RNA (circRNA) circ_0006174 can regulate chemoresistance of doxorubicin (DOX) in colorectal cancer via exosomes. Forty-one pairs of normal and CRC (DOX sensitive, n = 16; DOX resistant, n = 25) samples were collected. The resistant cell lines (LoVo/DOX and HCT116/DOX) were constructed by exposure of parental cell lines (LoVo and HCT116) to DOX. The detection of circ_0006174, microRNA-1205 (miR-1205), and cyclin D2 (CCND2) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8(CCK-8) was applied for determining the half of inhibitory concentration (IC50) of DOX and cell proliferation. The migration and invasion capacities were analyzed via transwell assay. Exosomes were extracted using ultracentrifugation. Protein levels were determined using western blot. Dual-luciferase reporter assay was used for affirming target interaction. In vivo experiment was performed by establishing xenograft models in mice. Circ_0006174 level was upregulated in DOX-resistant CRC tissues and cells. The downregulation of circ_0006174 inhibited DOX resistance, cell proliferation, migration, and invasion in DOX-resistant CRC cells. Interestingly, the abundant circ_0006174 was enriched in exosomes derived from DOX-resistant CRC cells. Furthermore, circ_0006174 could enhance DOX resistance via the exosomal intercellular transfer. Moreover, we validated the target relation of circ_0006174/miR-1205 or miR-1205/CCND2. The effect of exosomal circ_0006174 on DOX resistance was achieved by upregulating the miR-1205-mediated CCND2. In vivo, knockdown of circ_0006174 also enhanced tumor sensitivity to DOX by targeting miR-1205/CCND2 axis. Altogether, these findings unraveled that circ_0006174-enriched exosomes elevated DOX chemoresistance in CRC by the miR-1205/CCND2 axis. The exosomal circ_0006174 can be used as an available biomarker for the diagnosis of chemoresistance in CRC.

A novel intracellular peptide derived from g1/s cyclin d2 induces cell death.

Intracellular peptides are constantly produced by the ubiquitin-proteasome system, and many are probably functional. Here, the peptide WELVVLGKL (pep5) from G1/S-specific cyclin D2 showed a 2-fold increase during the S phase of HeLa cell cycle. pep5 (25-100 µm) induced cell death in several tumor cells only when it was fused to a cell-penetrating peptide (pep5-cpp), suggesting its intracellular function. In vivo, pep5-cpp reduced the volume of the rat C6 glioblastoma by almost 50%. The tryptophan at the N terminus of pep5 is essential for its cell death activity, and N terminus acetylation reduced the potency of pep5-cpp. WELVVL is the minimal active sequence of pep5, whereas Leu-Ala substitutions totally abolished pep5 cell death activity. Findings from the initial characterization of the cell death/signaling mechanism of pep5 include caspase 3/7 and 9 activation, inhibition of Akt2 phosphorylation, activation of p38α and -γ, and inhibition of proteasome activity. Further pharmacological analyses suggest that pep5 can trigger cell death by distinctive pathways, which can be blocked by IM-54 or a combination of necrostatin-1 and q-VD-OPh. These data further support the biological and pharmacological potential of intracellular peptides.

Cyclin D2 is essential for the compensatory beta-cell hyperplastic response to insulin resistance in rodents.

OBJECTIVE: A major determinant of the progression from insulin resistance to the development of overt type 2 diabetes is a failure to mount an appropriate compensatory beta-cell hyperplastic response to maintain normoglycemia. We undertook the present study to directly explore the significance of the cell cycle protein cyclin D2 in the expansion of beta-cell mass in two different models of insulin resistance. RESEARCH DESIGN AND METHODS: We created compound knockouts by crossing mice deficient in cyclin D2 (D2KO) with either the insulin receptor substrate 1 knockout (IRS1KO) mice or the insulin receptor liver-specific knockout mice (LIRKO), neither of which develops overt diabetes on its own because of robust compensatory beta-cell hyperplasia. We phenotyped the double knockouts and used RT-qPCR and immunohistochemistry to examine beta-cell mass. RESULTS: Both compound knockouts, D2KO/LIRKO and D2KO/IRS1KO, exhibited insulin resistance and hyperinsulinemia and an absence of compensatory beta-cell hyperplasia. However, the diabetic D2KO/LIRKO group rapidly succumbed early compared with a relatively normal lifespan in the glucose-intolerant D2KO/IRS1KO mice. CONCLUSIONS: This study provides direct genetic evidence that cyclin D2 is essential for the expansion of beta-cell mass in response to a spectrum of insulin resistance and points to the cell-cycle protein as a potential therapeutic target that can be harnessed for preventing and curing type 2 diabetes.