Protein arginine methyltransferase 1 regulates cell proliferation and differentiation in adult mouse adult intestine
Xue, L;Bao, L;Roediger, J;Su, Y;Shi, B;Shi, YB;
PMID: 34158114 | DOI: 10.1186/s13578-021-00627-z
Adult stem cells play an essential role in adult organ physiology and tissue repair and regeneration. While much has been learnt about the property and function of various adult stem cells, the mechanisms of their development remain poorly understood in mammals. Earlier studies suggest that the formation of adult mouse intestinal stem cells takes place during the first few weeks after birth, the postembryonic period when plasma thyroid hormone (T3) levels are high. Furthermore, deficiency in T3 signaling leads to defects in adult mouse intestine, including reduced cell proliferation in the intestinal crypts, where stem cells reside. Our earlier studies have shown that protein arginine methyltransferase 1 (PRMT1), a T3 receptor coactivator, is highly expressed during intestinal maturation in mouse.We have analyzed the expression of PRMT1 by immunohistochemistry and studied the effect of tissue-specific knockout of PRMT1 in the intestinal epithelium.We show that PRMT1 is expressed highly in the proliferating transit amplifying cells and crypt base stem cells. By using a conditional knockout mouse line, we have demonstrated that the expression of PRMT1 in the intestinal epithelium is critical for the development of the adult mouse intestine. Specific removal of PRMT1 in the intestinal epithelium results in, surprisingly, more elongated adult intestinal crypts with increased cell proliferation. In addition, epithelial cell migration along the crypt-villus axis and cell death on the villus are also increased. Furthermore, there are increased Goblet cells and reduced Paneth cells in the crypt while the number of crypt base stem cells remains unchanged.Our finding that PRMT1 knockout increases cell proliferation is surprising considering the role of PRMT1 in T3-signaling and the importance of T3 for intestinal development, and suggests that PRMT1 likely regulates pathways in addition to T3-signaling to affect intestinal development and/or homeostasis, thus affecting cell proliferating and epithelial turn over in the adult.
Proc Natl Acad Sci U S A.
Labouesse MA, Sartori AM, Weinmann O, Simpson EH, Kellendonk C, Weber-Stadlbauer U.
PMID: 30254156 | DOI: 10.1073/pnas.1800171115
Dopaminergic signaling in the striatum, particularly at dopamine 2 receptors (D2R), has been a topic of active investigation in obesity research in the past decades. However, it still remains unclear whether variations in striatal D2Rs modulate the risk for obesity and if so in which direction. Human studies have yielded contradictory findings that likely reflect a complex nonlinear relationship, possibly involving a combination of causal effects and compensatory changes. Animal work indicates that although chronic obesogenic diets reduce striatal D2R function, striatal D2R down-regulation does not lead to obesity. In this study, we evaluated the consequences of striatal D2R up-regulation on body-weight gain susceptibility and energy balance in mice. We used a mouse model of D2R overexpression (D2R-OE) in which D2Rs were selectively up-regulated in striatal medium spiny neurons. We uncover a pathological mechanism by which striatal D2R-OE leads to reduced brown adipose tissue thermogenesis, reduced energy expenditure, and accelerated obesity despite reduced eating. We also show that D2R-OE restricted to development is sufficient to promote obesity and to induce energy-balance deficits. Together, our findings indicate that striatal D2R-OE during development persistently increases the propensity for obesity by reducing energy output in mice. This suggests that early alterations in the striatal dopamine system could represent a key predisposition factor toward obesity.
Virchows Arch. 2015 Jun 13.
Olfactomedin 4 (OLFM4) has been demonstrated to be upregulated in various cancers and involved in many cellular processes such as cell adhesion, apoptosis, and cell proliferation. In gastric cancer, clinicopathological relevance of OLFM4 expression has been reported. However, there are few studies showing how expression of OLFM4 evolves during multistep gastric carcinogenesis. In this study, we investigated OLFM4 expression during gastric carcinogenesis using RNA in situ hybridization (ISH). We found that OLFM4 expression is absent in normal gastric mucosa, begins to appear at the isthmus region in gastric glands in chronic gastritis, and is remarkably increased in intestinal metaplasia (IM). Interestingly, gastric-type glands around IM frequently expressed OLFM4 before CDX2 was expressed, suggesting that OLFM4 might be involved in regulating CDX2 expression. However, overexpression of OLFM4 failed to induce CDX2 transcription. All gastric adenomas were strongly positive for OLFM4. OLFM4 expression was higher in intestinal type, well to moderately differentiated and early-stage adenocarcinomas, and decreased in poorly differentiated and advanced-stage gastric cancer (GC). Although OLFM4 expression had no prognostic value for GC overall (P = 0.441), it was associated with poor survival of GC in stage II, III, and IV (P = 0.018), suggesting that OLFM4 expression has prognostic significance for late-stage GC. Our findings suggest that OLFM4 is not only involved in early stages of gastric carcinogenesis but also a useful prognostic marker for advanced GC, which is encouraging for further studies exploring OLFM4 as a potential target for therapy of GC.
PLoS One. 2015 May 21;10(5):e0127300.
Jang BG, Lee BL, Kim WH.
PMID: 26015511 | DOI: clincanres.3357.2014.
Gastric intestinal metaplasia (IM) is a highly prevalent preneoplastic lesion; however, the molecular mechanisms regulating its development remain unclear. We have previously shown that a population of cells expressing the intestinal stem cell (ISC) marker LGR5 increases remarkably in IM. In this study, we further investigated the molecular characteristics of these LGR5+ cells in IM by examining the expression profile of several ISC markers. Notably, we found that ISC markers-including OLFM4 and EPHB2-are positively associated with the CDX2 expression in non-tumorous gastric tissues. This finding was confirmed in stomach lesions with or without metaplasia, which demonstrated that OLFM4 and EPHB2 expression gradually increased with metaplastic progression. Moreover, RNA in situ hybridization revealed that LGR5+ cells coexpress several ISC markers and remained confined to the base of metaplastic glands, reminiscent to that of normal intestinal crypts, whereas those in normal antral glands expressed none of these markers. Furthermore, a large number of ISC marker-expressing cells were diffusely distributed in gastric adenomas, suggesting that these markers may facilitate gastric tumorigenesis. In addition, Barrett's esophagus (BE)-which is histologically similar to intestinal metaplasia-exhibited a similar distribution of ISC markers, indicating the presence of a stem cell population with intestinal differentiation potential. In conclusion, we identified that LGR5+ cells in gastric IM and BE coexpress ISC markers, and exhibit the same expression profile as those found in normal intestinal crypts. Taken together, these results implicate an intestinal-like stem cell population in the pathogenesis of IM, and provide an important basis for understanding the development and maintenance of this disease.
Brain : a journal of neurology
Ray, PR;Shiers, S;Caruso, JP;Tavares-Ferreira, D;Sankaranarayanan, I;Uhelski, ML;Li, Y;North, RY;Tatsui, C;Dussor, G;Burton, MD;Dougherty, PM;Price, TJ;
PMID: 35867896 | DOI: 10.1093/brain/awac266
Neuropathic pain is a leading cause of high impact pain, is often disabling and is poorly managed by current therapeutics. Here we focused on a unique group of neuropathic pain patients undergoing thoracic vertebrectomy where the dorsal root ganglia is removed as part of the surgery allowing for molecular characterization and identification of mechanistic drivers of neuropathic pain independently of preclinical models. Our goal was to quantify whole transcriptome RNA abundances using RNA-seq in pain-associated human dorsal root ganglia from these patients, allowing comprehensive identification of molecular changes in these samples by contrasting them with non-pain associated dorsal root ganglia. We sequenced 70 human dorsal root ganglia, and among these 50 met inclusion criteria for sufficient neuronal mRNA signal for downstream analysis. Our expression analysis revealed profound sex differences in differentially expressed genes including increase of IL1B, TNF, CXCL14, and OSM in male and including CCL1, CCL21, PENK and TLR3 in female dorsal root ganglia associated with neuropathic pain. Co-expression modules revealed enrichment in members of JUN-FOS signalling in males, and centromere protein coding genes in females. Neuro-immune signalling pathways revealed distinct cytokine signalling pathways associated with neuropathic pain in males (OSM, LIF, SOCS1) and females (CCL1, CCL19, CCL21). We validated cellular expression profiles of a subset of these findings using RNAscope in situ hybridization. Our findings give direct support for sex differences in underlying mechanisms of neuropathic pain in patient populations.
Sheahan, BJ;Theriot, CM;Cortes, JE;Dekaney, CM;
PMID: 35012435 | DOI: 10.1080/19490976.2021.2018898
Acute intestinal mucositis is a common off-target effect of chemotherapy, leading to co-morbidities such as vomiting, diarrhea, sepsis, and death. We previously demonstrated that the presence of enteric bacteria modulates the extent of jejunal epithelial damage induced by doxorubicin (DXR) in mice. Despite conventional thinking of the crypt as a sterile environment, recent evidence suggests that bacterial signaling influences aISC function. In this study, we labeled aISCs using transgenic Lgr5-driven fluorescence or with immunostaining for OLFM4. We examined the effect of DXR in both germ free (GF) mice and mice depleted of microbiota using an established antimicrobial treatment protocol (AMBx). We found differences in DXR-induced loss of aISCs between GF mice and mice treated with AMBx. aISCs were decreased after DXR in GF mice, whereas AMBx mice retained aISC expression after DXR. Neither group of mice exhibited an inflammatory response to DXR, suggesting the difference in aISC retention was not due to differences in local tissue inflammation. Therefore, we suspected that there was a protective microbial signal present in the AMBx mice that was not present in the GF mice. 16S rRNA sequencing of jejunal luminal contents demonstrated that AMBx altered the fecal and jejunal microbiota. In the jejunal contents, AMBx mice had increased abundance of Ureaplasma and Burkholderia. These results suggest pro-survival signaling from microbiota in AMBx-treated mice to the aISCs, and that this signaling maintains aISCs in the face of chemotherapeutic injury. Manipulation of the enteric microbiota presents a therapeutic target for reducing the severity of chemotherapy-associated mucositis.
Harris NA, Isaac AT, Günther A, Merkel K, Melchior J, Xu M, Eguakun E, Perez R, Nabit BP, Flavin S, Gilsbach R, Shonesy B, Hein L, Abel T, Baumann A, Matthews R, Centanni SW, Winder DG.
PMID: 30150361 | DOI: 10.1523/JNEUROSCI.0963-18.2018
Stress is a precipitating agent in neuropsychiatric disease and initiates relapse to drug-seeking behavior in addicted patients. Targeting the stress system in protracted abstinence from drugs of abuse with anxiolytics may be an effective treatment modality for substance use disorders. α2A-adrenergic receptors (α2A-ARs) in extended amygdala structures play key roles in dampening stress responses. Contrary to early thinking, α2A-ARs are expressed at non-noradrenergic sites in the brain. These non-noradrenergic α2A-ARs play important roles in stress-responses, but their cellular mechanisms of action are unclear. In humans, the α2A-AR agonist guanfacine reduces overall craving and uncouples craving from stress yet minimally affects relapse, potentially due to competing actions in the brain. Here we show that heteroceptor α2A-ARs postsynaptically enhance dorsal BNST (dBNST) neuronal activity in mice of both sexes. This effect is mediated by hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels, as inhibition of these channels is necessary and sufficient for excitatory actions. Finally, this excitatory action is mimicked by clozapine-N-oxide activation of the Gi-coupled DREADD hM4Di in dBNST neurons, and its activation elicits anxiety-like behavior in the elevated plus maze. Together, this data provides a framework for elucidating cell-specific actions of GPCR signaling and provides a potential mechanism whereby competing anxiogenic and anxiolytic actions of guanfacine may affect its clinical utility in the treatment of addiction.SIGNIFICANCE STATEMENTStress impacts the development of neuropsychiatric disorders including anxiety and addiction. Guanfacine is an α2A-adrenergic receptor (α2A-AR) agonist with actions in the bed nucleus of the stria terminalis (BNST) that produces antidepressant actions and uncouples stress from reward-related behaviors. Here we show that guanfacine increases dBNST neuronal activity through actions at postsynaptic α2A-ARs via a mechanism that involves hyperpolarization-activated cyclic nucleotide gated cation (HCN) channels. This action is mimicked by activation of the designer receptor hM4Di expressed in the BNST, which also induces anxiety-like behaviors. Together, these data suggest 1) that postsynaptic α2A-ARs in BNST have excitatory actions on BNST neurons, and 2) these actions can be phenocopied by the so-called "inhibitory" DREADDs, suggesting care must be taken regarding interpretation of data obtained with these tools.
Abstract Aims Intestinal stem cell (ISC) markers such as LGR5, ASCL2, EPHB2 and OLFM4 and their clinical implications have been extensively studied in colorectal cancers (CRCs). However, little is known about their expression in precancerous lesions of CRCs. Here, we investigated the expression and distribution of ISC markers in serrated polyps and conventional adenomas. Methods and results RT-PCR analysis revealed that all ISC markers were significantly upregulated in conventional adenomas with low grade dysplasia (CALGs) compared with other lesions. RNA in situ hybridization confirmed that CALGs exhibited strong and diffuse expression of all ISC markers, which indicate a stem cell-like phenotype. However, normal colonic mucosa hyperplastic polyps and sessile serrated adenomas harbored LGR5+ cells that were confined to the crypt base and demonstrated an organized expression of ISC markers. Notably, in traditional serrated adenomas, expression of LGR5 and ASCL2 was localized to the ectopic crypts as in the normal crypts, but expression of EPHB2 and OLFM4 was distributed in a diffuse manner, which is suggestive of a progenitor-like features. Conclusions The expression and distribution profile of ISC markers possibly provides insights into the organization of stem and progenitor-like cells in each type of precancerous lesion of CRC
Ahn SY, Kim J, Kim MA, Choi J, Kim WH.
PMID: 28314274 | DOI: -
Abstract
BACKGROUND:
Increased expression of hepatocyte growth factor (HGF) and MET proto-oncogene (c-MET) is associated with poor prognosis in various cancer types. Recently, it was reported that the expression of HGF induces resistance to tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor, human epidermal receptor receptor 2, and b-raf proto-oncogene. Here, we investigated the effects of HGF overexpression in gastric cancer cells in the absence or presence of c-MET TKIs.
MATERIALS AND METHODS:
The effects of c-MET TKIs in gastric cancer cells with and without c-MET overexpression were determined in gastric cancer cell lines with various cell biology methods.
RESULTS:
Compared to the control, cells with induced expression of HGF showed increase in anchorage-independent colony formation (p<0.001). The c-MET TKIs inhibited HGF/c-MET downstream signaling, cell proliferation, migration and invasion, and triggered cell-cycle arrest in Hs746T cells. However, HGF-transfected cells were less affected.
CONCLUSION:
c-MET TKIs had inhibitory effects only on cells overexpressing c-MET. Furthermore, overexpression of HGF resulted in resistance to c-MET TKIs through an autocrine manner in gastric cancer cells.
Yu, B;Zhang, Q;Lin, L;Zhou, X;Ma, W;Wen, S;Li, C;Wang, W;Wu, Q;Wang, X;Li, XM;
PMID: 36788214 | DOI: 10.1038/s41421-022-00506-y
The amygdala, or an amygdala-like structure, is found in the brains of all vertebrates and plays a critical role in survival and reproduction. However, the cellular architecture of the amygdala and how it has evolved remain elusive. Here, we generated single-nucleus RNA-sequencing data for more than 200,000 cells in the amygdala of humans, macaques, mice, and chickens. Abundant neuronal cell types from different amygdala subnuclei were identified in all datasets. Cross-species analysis revealed that inhibitory neurons and inhibitory neuron-enriched subnuclei of the amygdala were well-conserved in cellular composition and marker gene expression, whereas excitatory neuron-enriched subnuclei were relatively divergent. Furthermore, LAMP5+ interneurons were much more abundant in primates, while DRD2+ inhibitory neurons and LAMP5+SATB2+ excitatory neurons were dominant in the human central amygdalar nucleus (CEA) and basolateral amygdalar complex (BLA), respectively. We also identified CEA-like neurons and their species-specific distribution patterns in chickens. This study highlights the extreme cell-type diversity in the amygdala and reveals the conservation and divergence of cell types and gene expression patterns across species that may contribute to species-specific adaptations.
Cooley, A;Madhukaran, S;Stroebele, E;Colon Caraballo, M;Wang, L;Akgul, Y;Hon, GC;Mahendroo, M;
PMID: 36718364 | DOI: 10.1016/j.isci.2023.105953
The cervical epithelium undergoes changes in proliferation, differentiation, and function that are critical to ensure fertility and maintain pregnancy. Here, we identify cervical epithelial subtypes in non-pregnant, pregnant, and in labor mice using single-cell transcriptome and spatial analysis. We identify heterogeneous subpopulations of epithelia displaying spatial and temporal specificity. Notably in pregnancy, two goblet cell subtypes are present in the most luminal layers with one goblet population expanding earlier in pregnancy than the other goblet population. The goblet populations express novel protective factors and distinct mucosal networks. Single-cell analysis in a model of cervical epithelial barrier disruption indicates untimely basal cell proliferation precedes the expansion of goblet cells with diminished mucosal integrity. These data demonstrate how the cervical epithelium undergoes continuous remodeling to maintain dynamic states of homeostasis in pregnancy and labor, and provide a framework to understand perturbations in epithelial health that increase the risk of premature birth.
Cloft, SE;Kinstler, SR;Reno, KE;Sellers, HS;Franca, M;Ecco, R;Lee, MD;Maurer, JJ;Wong, EA;
PMID: 35191652 | DOI: 10.1637/21-00109
Runting stunting syndrome (RSS) in broiler chickens is characterized by altered intestinal morphology and gene expression and stunted growth. The objective of this study was to conduct a retrospective study of gene expression in stem and differentiated cells in the small intestine of RSS chicks. Two different models of RSS were analyzed: broiler chicks that were experimentally infected and broiler chicks that were naturally infected. Experimentally infected chicks were exposed to litter from infected flocks (RSS-litter chicks) or infected with astrovirus (RSS-astrovirus chicks). Intestinal samples from naturally infected chicks showing clinical signs of RSS were acquired from commercial farms in Georgia and were brought into a poultry diagnostic lab (RSS-clinical-GA) and from farms in Brazil that had a history of RSS (RSS-clinical-BR). The RSS-clinical-BR chicks were separated into those that were positive or negative for gallivirus based on DNA sequencing. Intestinal morphology and intestinal cell type were identified in archived formalin-fixed, paraffin-embedded tissues. In situ hybridization for cell-specific mRNA was used to identify intestinal stem cells expressing olfactomedin 4 (Olfm4), proliferating cells expressing Ki67, absorptive cells expressing sodium glucose cotransporter 1 (SGLT1) and peptide transporter 1 (PepT1), and goblet cells expressing mucin 2 (Muc2). RSS-litter and RSS-clinical-GA chicks showed 4% to 7.5% cystic crypts, while gallivirus-positive RSS-clinical-BR chicks showed 11.7% cystic crypts. RSS-astrovirus and gallivirus-negative RSS-clinical-BR chicks showed few cystic crypts. RSS-litter and gallivirus-positive RSS-clinical-BR chicks showed an increase in crypt depth compared to control or gallivirus-negative chicks, respectively. There was no expression of Olfm4 mRNA in the stem cells of RSS-litter and RSS-clinical-GA chicks, in contrast to the normal expression of Olfm4 mRNA in RSS-astrovirus and RSS-clinical-BR chicks. All chicks regardless of infection status showed normal expression of Ki67 mRNA in crypt cells, Muc2 mRNA in goblet cells, and SGLT1 or PepT1 mRNA in enterocytes. These results demonstrate that RSS, which can be induced by different etiologies, can show differences in the expression of the stem cell marker Olfm4.
