Probes for INS

Wnt5a is a non-canonical Wnt ligand that is essential for normal embryonic development in mammals. The role of Wnt5a in early intestinal development has been examined in gene ablation models, where _Wnt5a__−/−_ mice exhibit strikingly shortened intestines. However, the exact cellular source of Wnt5a has remained elusive, until a recent study found that FoxL1-expressing mesenchymal cells (FoxL1+ cells), which are localized directly beneath the intestinal epithelium, express Wnt5a. To determine whether FoxL1+ cells are a required source of Wnt5a during intestinal development, we derived _FoxL1-Cre; Wnt5a__f/f_ mice, which is the first mouse model to ablate Wnt5a in a cell type-specific manner in the intestine _in vivo_. Our results show that Wnt5a deletion in FoxL1+ cells during fetal life causes a shortened gut phenotype in neonatal mice, and that our model is sufficient to increase rate of apoptosis in the elongating epithelium, thus explaining the shortened gut phenotype. However, in contrast to previous studies using Wnt5a null mice, we did not observe dysregulation of epithelial structure or apical-basal protein localization. Altogether, our findings establish a developmental role for FoxL1+ mesenchymal cells in controlling non-canonical Wnt signaling during midgut elongation.

Tumor microenvironment (TME) exerts key roles in pancreatic ductal adenocarcinoma (PDAC) development. However, the factors regulating the cross-talk between PDAC cells and TME are largely unknown. In the present study, we identified a long noncoding RNA (lncRNA) KLHDC7B divergent transcript (KLHDC7B-DT), which was up-regulated in PDAC and correlated with poor survival of PDAC patients. Functional assays demonstrated that KLHDC7B-DT enhanced PDAC cell proliferation, migration, and invasion. Mechanistically, KLHDC7B-DT was found to directly bind IL-6 promoter, induce open chromatin structure at IL-6 promoter region, activate IL-6 transcription, and up-regulate IL-6 expression and secretion. The expression of KLHDC7B-DT was positively correlated with IL-6 in PDAC tissues. Via inducing IL-6 secretion, KLHDC7B-DT activated STAT3 signaling in PDAC cells in an autocrine manner. Furthermore, KLHDC7B-DT also activated STAT3 signaling in macrophages in a paracrine manner, which induced macrophage M2 polarization. KLHDC7B-DT overexpressed PDAC cells-primed macrophages promoted PDAC cell proliferation, migration, and invasion. Blocking IL-6/STAT3 signaling reversed the effects of KLHDC7B-DT on macrophage M2 polarization and PDAC cell proliferation, migration, and invasion. In conclusion, KLHDC7B-DT enhanced malignant behaviors of PDAC cells via IL-6-induced macrophage M2 polarization and IL-6-activated STAT3 signaling in PDAC cells. The cross-talk between PDAC cells and macrophages induced by KLHDC7B-DT represents potential therapeutic target for PDAC.

To define the contribution of CD8+ T cell responses to control of SIV reactivation during and following antiretroviral therapy (ART), we determined the effect of long-term CD8+ T cell depletion using a rhesusized anti-CD8β monoclonal antibody (mAb) on barcoded SIVmac239 dynamics on stable ART and after ART cessation in Rhesus Macaques (RMs). Among the RMs with full CD8+ T cell depletion in both blood and tissue, there were no significant differences in the frequency of viral blips in plasma, the number of SIV RNA+ cells and the average number of RNA copies/infected cell in tissue, and levels of cell-associated SIV RNA and DNA in blood and tissue relative to control-treated RM during ART. Upon ART cessation, both CD8+ T cell-depleted and control RMs rebounded in <12 days with no difference in the time to viral rebound, or in either the number or growth rate of rebounding SIVmac239M barcode clonotypes. However, effectively CD8+ T cell-depleted RMs showed a stable ~2-log increase in post-ART plasma viremia relative to controls. These results indicate that while potent anti-viral CD8+ T cell responses can develop during ART-suppressed SIV infection, these responses effectively intercept post-ART SIV rebound only after systemic viral replication, too late to limit reactivation frequency or the early spread of reactivating SIV reservoirs.

The placenta is formed by the coordinated expansion and differentiation of trophoblast stem (TS) cells along a multi-lineage pathway. Dynamic regulation of histone 3 lysine 9 (H3K9) methylation is pivotal to cell differentiation for many cell lineages, but little is known about its involvement in trophoblast cell development. Expression of H3K9 methyltransferases was surveyed in rat TS cells maintained in the stem state and following differentiation. The role of suppressor of variegation 3-9 homolog 2 (SUV39H2) in the regulation of trophoblast cell lineage development was investigated using a loss-of-function approach in rat TS cells and ex vivo cultured rat blastocysts. Among the twelve-known H3K9 methyltransferases, only SUV39H2 exhibited robust differential expression in stem versus differentiated TS cells. SUV39H2 transcript and protein expression were high in the stem state and declined as TS cells differentiated. Disruption of SUV39H2 expression in TS cells led to an arrest in TS cell proliferation and activation of trophoblast cell differentiation. SUV39H2 regulated H3K9 methylation status at loci exhibiting differentiation-dependent gene expression. Analyses of SUV39H2 on ex vivo rat blastocyst development supported its role in regulating TS cell expansion and differentiation. We further identified SUV39H2 as a downstream target of caudal type homeobox 2, a master regulator of trophoblast lineage development. Our findings indicate that SUV39H2 contributes to the maintenance of TS cells and restrains trophoblast cell differentiation. SUV39H2 serves as a contributor to the epigenetic regulation of hemochorial placental development.

Astrocytes are glial cells proposed as the main Sonic Hedgehog (Shh)-responsive cells in the adult brain. Their roles in mediating Shh functions are still poorly understood. In the hypothalamus, astrocytes support neuronal circuits implicated in the regulation of energy metabolism. Here, we investigated the impact of genetic activation of Shh signaling on hypothalamic astrocytes and characterized its effects on energy metabolism. We analyzed the distribution of gene transcripts of the Shh pathway (Ptc, Gli1, Gli2, Gli3) in astrocytes using single molecule fluorescence in situ hybridization combined to immunohistofluorescence and of Shh peptides by Western blotting in the adult mouse hypothalamus. Based on the metabolic phenotype, we characterized Glast-CreERT2-YFP-Ptc-/- (YFP-Ptc-/-) mice and their controls over time and under high-fat-diet (HFD) to investigate the potential effects of conditional astrocytic deletion of the Shh receptor Patched (Ptc) on metabolic efficiency, insulin sensitivity and systemic glucose metabolism. Molecular and biochemical assays were used to analyze the alteration of key pathways modulating energy metabolism, insulin sensitivity, glucose uptake and inflammation. Primary astrocyte cultures were used to evaluate a potential role of Shh signaling in astrocytic glucose uptake. Shh peptides were the highest in the hypothalamic extracts of adult mice and a large population of hypothalamic astrocytes expressed Ptc and Gli1-3 mRNAs. Characterization of Shh signaling after conditional Ptc deletion in YFP-Ptc-/- mice revealed heterogeneity in hypothalamic astrocyte populations. Interestingly, the activation of Shh signaling in Glast+ astrocytes enhanced insulin responsiveness as evidenced by glucose and insulin tolerance tests. This effect was maintained over time and associated with lower blood insulin levels and was also observed under HFD. YFP-Ptc-/- mice exhibited a lean phenotype with the absence of body weight gain and a marked reduction of white and brown adipose tissues accompanied by increased whole body fatty acid oxidation. In contrast, food intake, locomotor activity and body temperature were not altered. At the cellular level, Ptc deletion did not affect glucose uptake in primary astrocyte cultures. In the hypothalamus, the activation of astrocytic Shh pathway was associated with the upregulation of transcripts coding for the insulin receptor and the Liver Kinase B1 (LKB1) after 4 weeks, and for the glucose transporter Glut-4 after 32 weeks. Here, we define hypothalamic Shh action on astrocytes as a novel master regulator of energy metabolism. In the hypothalamus, astrocytic Shh signaling could be critically involved in preventing both aging- and obesity-related metabolic disorders.

Maturation of the definitive adrenal cortex occurs between 3 and 6 weeks post-partum and involves onset of CYP11B2 expression and establishment of the laminin-encased 3D structure of glomeruli that contain rosettes of 10 to 15 zona glomerulosa (zG) cells that work in coordination to produce optimal amounts of aldosterone. Although this process is dependent on canonical WNT/b-catenin signaling, cellular sources of WNT ligands remain elusive and the mechanisms involved in the extensive extra-cellular matrix remodeling associated with rosette/glomeruli morphogenesis are unknown. Beyond their role in innate immunity, macrophages are involved in extra-cellular matrix remodeling under a wide variety of pathophysiological conditions and have the capacity to produce WNT ligands. This, together with the presence of macrophages within the zG cells, strongly suggest that macrophages may play a role in zG morphogenesis and differentiation. Supporting this idea, a recent publication has shown that intra-tissular aldosterone concentration was reduced in the absence of macrophages under stress conditions. However, whether macrophages play a direct role in controlling aldosterone secretion or an indirect role by remodelling the postnatal zG is unknown. The presence of tissue resident macrophages in a specific zone is dependent on the production of trophic factors such as IL34, CSF1, CSF2 or CX3CL1 by nearby, tissue resident ‘niche’ cells. In return, macrophages are thought to provide positive ‘feedback’ signals to their niche, generating mutually beneficial circuits between the niche and its macrophages. To gain insight into the role of macrophages in zG morphogenesis and homeostasis, we used single cell sequencing and RNAscope analyses to show expression of CX3CL1 in the zG and of CX3CR1 in macrophages. Interestingly, CX3CL1 expression in the zG was downstream of WNT signalling, suggesting existence of a bi-directional interaction between macrophages and zG. To further study the role of macrophages during the maturation of the zG, we pharmacologically depleted macrophages by the small molecule inhibitor Pexidartinib at different time points between 3- and 12-weeks post-partum, when maturation of the zG occurs. Short-term depletion of macrophages resulted in a more disorganized and elongated zG, suggesting a delay in maturation. However, long-term depletion of macrophages resulted in exacerbated maturation of the rosettes, suggesting that the short-term zG defect was followed by establishment of a compensatory mechanism to allow formation of rosettes even in the absence of macrophages. Whether these perturbations of the zG are correlated with an altered production of aldosterone is still under study.

A precise sequence of axon guidance events is required for the development of the ocular motor system. Three cranial nerves grow towards, and connect with, six extraocular muscles in a stereotyped pattern, in order to control eye movements. The signalling protein alpha2-chimaerin (α2-CHN) plays a pivotal role in the formation of the ocular motor system; mutations in CHN1, encoding α2-CHN, cause the human eye movement disorder Duane Retraction Syndrome (DRS). Our research has demonstrated that manipulation of α2-chn signalling in the zebrafish embryo leads to ocular motor axon wiring defects, although the signalling cascades regulated by α2-chn remain poorly understood. Here, we demonstrate that several cytoskeletal regulatory proteins - collapsin response mediator protein 2 (CRMP2), (encoded by the gene dpysl2), stathmin1 and stathmin 2 - bind to α2-CHN. dpysl2, stathmin1 and especially stathmin2 are expressed by ocular motor neurons. We find that manipulation of dpysl2 and of stathmins in zebrafish larvae leads to defects in both the axon wiring of the ocular motor system and the optokinetic reflex, impairing horizontal eye movements. Knockdowns of these molecules in zebrafish larvae of either sex caused axon guidance phenotypes that included defasciculation and ectopic branching; in some cases these phenotypes were reminiscent of DRS. chn1 knockdown phenotypes were rescued by overexpression of CRMP2 and STMN1, suggesting that these proteins act in the same signalling pathway. These findings suggest that CRMP2 and stathmins signal downstream of α2-CHN to orchestrate ocular motor axon guidance, and to control eye movements.Significance statementThe precise control of eye movement is crucial for the life of vertebrate animals, including humans. In humans, this control depends on the arrangement of nerve wiring of the ocular motor system, composed of three nerves and six muscles, a system that is conserved across vertebrate phyla. Mutations in the protein alpha2-chimaerin have previously been shown to cause eye movement disorders (squint) and axon wiring defects in humans. Our recent work has unravelled how alpha2-chimaerin co-ordinates axon guidance of the ocular motor system in animal models. In this paper, we demonstrate key roles for the proteins CRMP2 and stathmin 1/2 in the signalling pathway orchestrated by alpha2-chimaerin, potentially giving insight into the aetiology of eye movement disorders in humans.

Purpose : Mechanisms of axonal insult within the ONH in glaucoma are not fully understood. This study aimed to delineate ONH molecular alterations in chronic stages of glaucoma, in an inherited feline model with ONH structure comparable to humans. Methods : ONH tissues from 10 LTBP2mut/mut cats with glaucoma and 5 wt control cats (age 1-3 yrs) were used to generate cDNA libraries for RNAseq. Weekly intraocular pressure (IOP) data and optic nerve axon counts were available for all subjects. Differentially expressed genes (DEGs) were identified using DESeq2 (false discovery rate < 0.05), and g:Profiler was used for functional enrichment analysis. DEGs in chronic glaucoma were compared to DEGs in an RNA-seq dataset generated by our lab from ONH tissues of LTBP2mut/mut cats prior to axon degeneration. Transcriptomic findings were validated by RNAscope in situ hybridization (ISH) and by immunolabeling (IF) of archived ONH tissue sections. For confirmatory studies, data were compared between groups by two-tailed unpaired t-test or ANOVA (p < 0.05 considered significant). Results : Mean and cumulative IOP over 10mths prior to tissue collection were consistently higher in LTBP2mut/mut than in wt cats. Stratifying subjects by optic nerve damage based on histological evaluation (mild [MLD], moderate [MOD] and severe [SEV] damage), 77, 882 and 1878 DEGs were identified, respectively, in glaucoma relative to age-matched controls. Functional analysis of DEGs in chronic, established glaucoma (MOD and SEV groups) identified upregulated DEGs ascribed to cell adhesion, immune/inflammatory responses, and MAPK cascade, and downregulated DEGs associated with metabolism, fatty acid synthesis, actin cytoskeleton and myelination. Comparing these DEGs in established chronic glaucoma to those in pre-degenerative, early-stage disease, 111 DEGs were shared between stages, including significant upregulation of HP and TNC. ISH confirmed expression of HP and TNC in the ONH, but with sub-regional differences in expression. TNC was highly expressed in the prelaminar - laminar regions and HP in the laminar and retrolaminar regions. ISH and IF identified astrocytes as the predominant ONH cell-type expressing these gene products. Conclusions : Early and chronic stages of glaucoma share a reactive astrocyte molecular signature. Gene expression changes are more complex and enhanced in chronic glaucoma.

Dengue (DENV) and West Nile (WNV) viruses are arthropod-transmitted flaviviruses that respectively cause systemic vascular leakage and encephalitis syndromes in humans. However, the viral factors contributing to these specific clinical disorders are not completely understood. Flavivirus nonstructural protein 1 (NS1) is required for replication, expressed on the cell surface, and secreted as a soluble glycoprotein, reaching high levels in the blood of infected individuals. Extracellular DENV and WNV NS1 interact with host proteins and cells, have immune evasion functions, and promote endothelial dysfunction in a tissue-specific manner. To characterize how differences in DENV and WNV NS1 might function in pathogenesis, we generated WNV NS1 variants with substitutions corresponding to residues found in DENV NS1. We discovered that the substitution NS1-P101K led to reduced WNV infectivity of the brain and attenuated lethality in infected mice, although the virus replicated efficiently in cell culture and peripheral organs and bound at wild-type levels to brain endothelial cells and complement components. The P101K substitution resulted in reduced NS1 antigenemia in mice, and this was associated with reduced WNV spread to the brain. As exogenous administration of NS1 protein rescued WNV brain infectivity in mice, we conclude that circulating WNV NS1 facilitates viral dissemination into the central nervous system and impacts disease outcome. IMPORTANCE Flavivirus NS1 serves as an essential scaffolding molecule during virus replication but also is expressed on the cell surface and secreted as a soluble glycoprotein that circulates in the blood of infected individuals. Although extracellular forms of NS1 are implicated in immune modulation and in promoting endothelial dysfunction at blood-tissue barriers, it has been challenging to study specific effects of NS1 on pathogenesis without disrupting its key role in virus replication. Here we assessed West Nile virus (WNV) NS1 variants that do not affect virus replication and evaluated their effects on pathogenesis in mice. Our characterization of WNV NS1-P101K suggests that the levels of NS1 in circulation facilitate WNV dissemination to the brain and disease outcome. Our findings help understand the role of NS1 during flavivirus infection and support antiviral strategies for targeting circulating forms of NS1.

Background About 40 disease genes have been described to date for isolated congenital anomalies of the kidneys and urinary tract (CAKUT), the most common cause of childhood chronic kidney disease. However, these genes account for only 20% of cases. ARHGEF6, a guanine nucleotide exchange factor that is implicated in such biologic processes as cell migration and focal adhesion, acts downstream of integrin linked kinase (ILK) and parvin proteins. A genetic variant of ILK that causes murine renal agenesis abrogates the interaction of ILK with a murine focal adhesion protein encoded by Parva, leading to CAKUT in mice with this variant. Methods To identify novel genes that, when mutated, result in CAKUT, we performed exome sequencing in an international cohort of 1265 families with CAKUT. We also assessed the effects in vitro of wild-type and mutant ARHGEF6 proteins, as well as the effects of Arhgef6 deficiency in mouse and frog models. Results We detected six different hemizygous variants in the gene ARHGEF6 (which is located on the X chromosome in humans) in eight individuals from six families with CAKUT. In kidney cells, overexpression of wild-type ARHGEF6-but not proband-derived mutant ARHGEF6- increased active levels of CDC42/RAC1, induced lamellipodia formation, and stimulated PARVAdependent cell spreading. ARHGEF6 mutant proteins showed loss of interaction with PARVA. Three-dimensional MDCK cell cultures expressing ARHGEF6 mutant proteins exhibited reduced lumen formation and polarity defects. Arhgef6 deficiency in mouse and frog models recapitulated features of human CAKUT. Conclusions Deleterious variants in ARHGEF6 may cause dysregulation of integrin-parvinRAC1/CDC42 signaling, thereby leading to X-linked CAKUT.

Background Opioid discontinuation generates a withdrawal syndrome marked by increased negative affect. Increased symptoms of anxiety and dysphoria during opioid discontinuation are a significant barrier to achieving long-term abstinence in opioid-dependent individuals. While adaptations in the nucleus accumbens are implicated in the opioid abstinence syndrome, the precise neural mechanisms are poorly understood. Additionally, our current knowledge is limited to changes following natural and semi-synthetic opioids, despite recent increases in synthetic opioid use and overdose. Methods We used a combination of cell subtype specific viral-labeling and electrophysiology in male and female mice to investigate structural and functional plasticity in nucleus accumbens medium spiny neuron (MSNs) subtypes after fentanyl abstinence. We characterized molecular adaptations after fentanyl abstinence with subtype specific RNAseq and Weighted Gene Co-expression Network Analysis. We used viral-mediated gene transfer to manipulate the molecular signature of fentanyl abstinence in D1-MSNs. Results Here we show fentanyl abstinence increases anxiety-like behavior, decreases social interaction, and engenders MSN subtype-specific plasticity in both sexes. D1, but not D2-MSNs exhibit dendritic atrophy and an increase in excitatory drive. We identified a cluster of co-expressed dendritic morphology genes downregulated selectively in D1-MSNs that are transcriptionally co-regulated by E2F1. E2f1 expression in D1-MSNs protects against loss of dendritic complexity, altered physiology, and negative affect-like behaviors caused by fentanyl abstinence. Conclusion Our findings indicate fentanyl abstinence causes unique structural, functional, and molecular changes in nucleus accumbens D1-MSNs that can be targeted to alleviate negative affective symptoms during abstinence.

Fatty liver is closely associated with elevated concentrations of nonesterified fatty acids (NEFA) and a low level of very low-density lipoproteins (VLDL) in blood of dairy cows. High NEFA inhibit the VLDL synthesis and assembly, and cause hepatic triacylglycerol (TAG) deposition. Sirtuin 3 (SIRT3), a mitochondrial deacetylase, antagonizes NEFA-induced TAG accumulation through modulating expressions of fatty acid synthesis and oxidation genes in cow hepatocytes. However, the role of SIRT3 in the VLDL synthesis and assembly was largely unknown. Here we aimed to test whether SIRT3 would recover the synthesis and assembly of VLDL in cow hepatocytes induced by high NEFA. Primary cow hepatocytes were isolated from 3 Holstein cows. Hepatocytes were infected with SIRT3 overexpression adenovirus (Ad-SIRT3), SIRT3-short interfering (si) RNA, or first infected with Ad-SIRT3 and then incubated with 1.0 mM NEFA (Ad-SIRT3 + NEFA). Expressions of key genes in VLDL synthesis and the VLDL contents in cell culture supernatants were measured. SIRT3 overexpression significantly increased the mRNA abundance of microsomal triglyceride transfer protein (MTP), apolipoprotein B100 (ApoB100) and ApoE (p < 0.01), and raised VLDL contents in the supernatants (p < 0.01). However, SIRT3 silencing displayed a reverse effect in comparison to SIRT3 overexpression. Compared with NEFA treatment alone, the Ad-SIRT3 + NEFA significantly upregulated the mRNA abundance of MTP, ApoB100 and ApoE (p < 0.01), and increased VLDL contents in the supernatants (p < 0.01). Our data demonstrated that SIRT3 restored the synthesis and assembly of VLDL in cow hepatocytes challenged with NEFA, providing an in vitro basis for further investigations testing its feasibility against hepatic TAG accumulation in dairy cows during the perinatal period.