Melanocortin 4 receptor signals at the neuronal primary cilium to control food intake and body weight
The Journal of clinical investigation
Wang, Y;Bernard, A;Comblain, F;Yue, X;Paillart, C;Zhang, S;Reiter, JF;Vaisse, C;
PMID: 33938449 | DOI: 10.1172/JCI142064
The melanocortin 4 receptor (MC4R) plays a critical role in the long-term regulation of energy homeostasis, and mutations in the MC4R are the most common cause of monogenic obesity. However, the precise molecular and cellular mechanisms underlying the maintenance of energy balance within MC4R-expressing neurons are unknown. We recently reported that the MC4R localizes to the primary cilium, a cellular organelle that allows for partitioning of incoming cellular signals, raising the question of whether the MC4R functions in this organelle. Here, using mouse genetic approaches, we found that cilia were required specifically on MC4R-expressing neurons for the control of energy homeostasis. Moreover, these cilia were critical for pharmacological activators of the MC4R to exert an anorexigenic effect. The MC4R is expressed in multiple brain regions. Using targeted deletion of primary cilia, we found that cilia in the paraventricular nucleus of the hypothalamus (PVN) were essential to restrict food intake. MC4R activation increased adenylyl cyclase (AC) activity. As with the removal of cilia, inhibition of AC activity in the cilia of MC4R-expressing neurons of the PVN caused hyperphagia and obesity. Thus, the MC4R signaled via PVN neuron cilia to control food intake and body weight. We propose that defects in ciliary localization of the MC4R cause obesity in human inherited obesity syndromes and ciliopathies.
Muscarinic M4 and M5 receptor subtypes in the ventral subiculum differentially modulate alcohol seeking vs consumption in male alcohol preferring rats
British journal of pharmacology
Walker, LC;Huckstep, KL;Chen, NA;Hand, LJ;Lindsley, CW;Langmead, CJ;Lawrence, AJ;
PMID: 33942300 | DOI: 10.1111/bph.15513
Muscarinic acetylcholine receptors (mAChRs) mediate alcohol consumption and seeking in rats, and while M4 and M5 mAChRs have recently been implicated to mediate these behaviours in the striatum, their role in other regions remain unknown. The ventral tegmental area (VTA) and ventral subiculum (vSub) both densely express M4 and M5 mAChRs and modulate alcohol seeking via their projections to the nucleus accumbens shell (AcbSh). In Indiana alcohol preferring (iP) male rats we examined Chrm4 (M4 ) and Chrm5 (M5 ) expression in the VTA and vSub following long-term alcohol consumption and abstinence using RT-qPCR. Next, using a combination of retrograde tracing and RNAscope, we examined the localisation of Chrm4 and Chrm5 on vSub cells that project to the AcbSh. Using selective allosteric modulators, we examined the functional role of M4 and M5 mAChRs within the vSub in alcohol consumption, context-induced alcohol seeking, locomotor activity and food/water consumption. Long-term alcohol and abstinence dysregulated mAChR gene expression in the vSub, not VTA. Chrm4 was downregulated following long-term alcohol and abstinence, while Chrm5 was upregulated following long-term alcohol consumption. In line with these data, intra-vSub M4 positive allosteric modulator (VU0467154) reduced context-induced alcohol seeking, but not motivation for alcohol self-administration, while M5 negative allosteric modulator (ML375) reduced initial motivation for alcohol self-administration, but not context-induced alcohol seeking. Collectively our data highlight alcohol-induced cholinergic dysregulation in the vSub and distinct roles for M4 and M5 mAChR allosteric modulators to reduce alcohol consumption or seeking. This article is protected by
ARCGHR Neurons Regulate Muscle Glucose Uptake
de Lima, JBM;Debarba, LK;Rupp, AC;Qi, N;Ubah, C;Khan, M;Didyuk, O;Ayyar, I;Koch, M;Sandoval, DA;Sadagurski, M;
PMID: 34063647 | DOI: 10.3390/cells10051093
The growth hormone receptor (GHR) is expressed in brain regions that are known to participate in the regulation of energy homeostasis and glucose metabolism. We generated a novel transgenic mouse line (GHRcre) to characterize GHR-expressing neurons specifically in the arcuate nucleus of the hypothalamus (ARC). Here, we demonstrate that ARCGHR+ neurons are co-localized with agouti-related peptide (AgRP), growth hormone releasing hormone (GHRH), and somatostatin neurons, which are activated by GH stimulation. Using the designer receptors exclusively activated by designer drugs (DREADD) technique to control the ARCGHR+ neuronal activity, we demonstrate that the activation of ARCGHR+ neurons elevates a respiratory exchange ratio (RER) under both fed and fasted conditions. However, while the activation of ARCGHR+ promotes feeding, under fasting conditions, the activation of ARCGHR+ neurons promotes glucose over fat utilization in the body. This effect was accompanied by significant improvements in glucose tolerance, and was specific to GHR+ versus GHRH+ neurons. The activation of ARCGHR+ neurons increased glucose turnover and whole-body glycolysis, as revealed by hyperinsulinemic-euglycemic clamp studies. Remarkably, the increased insulin sensitivity upon the activation of ARCGHR+ neurons was tissue-specific, as the insulin-stimulated glucose uptake was specifically elevated in the skeletal muscle, in parallel with the increased expression of muscle glycolytic genes. Overall, our results identify the GHR-expressing neuronal population in the ARC as a major regulator of glycolysis and muscle insulin sensitivity in vivo.
Expression of Myosin 5a splice variants in murine stomach
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society
Carew, JA;Cristofaro, V;Siegelman, NA;Goyal, RK;Sullivan, MP;
PMID: 33939222 | DOI: 10.1111/nmo.14162
The motor protein, Myosin 5a (Myo5a) is known to play a role in inhibitory neurotransmission in gastric fundus. However, there is no information regarding the relative expression of total Myo5a, or of its alternative exon splice variants, across the stomach. This study investigated the differential distribution of Myo5a variants expressed within distinct anatomical regions of murine stomach. The distribution of Myo5a protein and mRNA in the stomach was assessed by immunofluorescence microscopy and fluorescent in situ hybridization. Quantitative PCR, restriction enzyme analysis, and electrophoresis were used to identify Myo5a splice variants and quantify their expression levels in the fundus, body, antrum, and pylorus. Myo5a protein colocalized with βIII-Tubulin in the myenteric plexus, and with synaptophysin in nerve fibers. Total Myo5a mRNA expression was lower in pylorus than in antrum, body, or fundus (p < 0.001), which expressed equivalent amounts of Myo5a. However, Myo5a splice variants were differentially expressed across the stomach. While the ABCE splice variant predominated in the antrum and body regions, the ACEF/ACDEF variants were enriched in fundus and pylorus. Myo5a splice variants varied in their relative expression across anatomically distinguishable stomach regions and might mediate distinct physiological functions in gastric neurotransmission. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.
Neuronal metabotropic glutamate receptor 8 protects against neurodegeneration in CNS inflammation
The Journal of experimental medicine
Woo, MS;Ufer, F;Rothammer, N;Di Liberto, G;Binkle, L;Haferkamp, U;Sonner, JK;Engler, JB;Hornig, S;Bauer, S;Wagner, I;Egervari, K;Raber, J;Duvoisin, RM;Pless, O;Merkler, D;Friese, MA;
PMID: 33661276 | DOI: 10.1084/jem.20201290
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with continuous neuronal loss. Treatment of clinical progression remains challenging due to lack of insights into inflammation-induced neurodegenerative pathways. Here, we show that an imbalance in the neuronal receptor interactome is driving glutamate excitotoxicity in neurons of MS patients and identify the MS risk-associated metabotropic glutamate receptor 8 (GRM8) as a decisive modulator. Mechanistically, GRM8 activation counteracted neuronal cAMP accumulation, thereby directly desensitizing the inositol 1,4,5-trisphosphate receptor (IP3R). This profoundly limited glutamate-induced calcium release from the endoplasmic reticulum and subsequent cell death. Notably, we found Grm8-deficient neurons to be more prone to glutamate excitotoxicity, whereas pharmacological activation of GRM8 augmented neuroprotection in mouse and human neurons as well as in a preclinical mouse model of MS. Thus, we demonstrate that GRM8 conveys neuronal resilience to CNS inflammation and is a promising neuroprotective target with broad therapeutic implications.
LncRNA PCIR Is an Oncogenic Driver via Strengthen the Binding of TAB3 and PABPC4 in Triple Negative Breast Cancer
Guo, W;Li, J;Huang, H;Fu, F;Lin, Y;Wang, C;
PMID: 34012913 | DOI: 10.3389/fonc.2021.630300
Long non-coding RNAs (LncRNA) as the key regulators in all stages of tumorigenesis and metastasis. However, the underlying mechanisms are largely unknown. Here, we report a lncRNA RP11-214F16.8, which renamed Lnc-PCIR, is upregulated and higher RNA level of Lnc-PCIR was positively correlated to the poor survival of patients with triple negative breast cancer (TNBC) tissues. Lnc-PCIR overexpression significantly promoted cell proliferation, migration, and invasion in vitro and in vivo. RNA pulldown, RNA immunoprecipitation (RIP) and RNA transcriptome sequencing technology (RNA-seq) was performed to identify the associated proteins and related signaling pathways. Mechanistically, higher Lnc-PCIR level of blocks PABPC4 proteasome-dependent ubiquitination degradation; stable and highly expressed PABPC4 can further increase the stability of TAB3 mRNA, meanwhile, overexpression of Lnc-PCIR can disrupt the binding status of TAB3 and TAB2 which lead to activate the TNF-α/NF-κB pathway in TNBC cells. Our findings suggest that Lnc-PCIR promotes tumor growth and metastasis via up-regulating the mRNA/protein level of TAB3 and PABPC4, activating TNF-α/NF-κB signaling pathway in TNBC.
Role for Mucin-5AC in Upper and Lower Airway Pathogenesis in Mice
Cho, HY;Park, S;Miller, L;Lee, HC;Langenbach, R;Kleeberger, SR;
PMID: 33938323 | DOI: 10.1177/01926233211004433
Mucin-5AC (MUC5AC) is a major secreted mucin in pathogenic airways. To determine its role in mucus-related airway disorders, Muc5ac-deficient (Muc5ac-/-) and wild-type (Muc5ac+/+) mice were compared in bleomycin-induced pulmonary fibrosis, respiratory syncytial virus (RSV) disease, and ozone toxicity. Significantly greater inflammation and fibrosis by bleomycin were developed in Muc5ac-/- lungs compared to Muc5ac+/+ lungs. More severe mucous cell metaplasia in fibrotic Muc5ac-/- lungs coincided with bronchial Muc2, Muc4, and Muc5b overexpression. Airway RSV replication was higher in Muc5ac-/- than in Muc5ac+/+ during early infection. RSV-caused pulmonary epithelial death, bronchial smooth muscle thickening, and syncytia formation were more severe in Muc5ac-/- compared to Muc5ac+/+. Nasal septal damage and subepithelial mucoserous gland enrichment by RSV were greater in Muc5ac-/- than in Muc5ac+/+. Ozone exposure developed more severe nasal airway injury accompanying submucosal gland hyperplasia and pulmonary proliferation in Muc5ac-/- than in Muc5ac+/+. Ozone caused periodic acid-Schiff-positive secretion only in Muc5ac-/- nasal airways. Lung E-cadherin level was relatively lower in Muc5ac-/- than in Muc5ac+/+ basally and after bleomycin, RSV, and ozone exposure. Results indicate that MUC5AC is an essential mucosal component in acute phase airway injury protection. Subepithelial gland hyperplasia and adaptive increase of other epithelial mucins may compensate airway defense in Muc5ac-/- mice.
B cells, antibody-secreting cells, and virus-specific antibodies respond to herpes simplex virus 2 reactivation in skin
The Journal of clinical investigation
Ford, ES;Sholukh, AM;Boytz, R;Carmack, SS;Klock, A;Phasouk, K;Shao, D;Rossenkhan, R;Edlefsen, PT;Peng, T;Johnston, C;Wald, A;Zhu, J;Corey, L;
PMID: 33784252 | DOI: 10.1172/JCI142088
Tissue-based T cells are important effectors in the prevention and control of mucosal viral infections; less is known about tissue-based B cells. We demonstrate that B cells and antibody-secreting cells (ASCs) are present in inflammatory infiltrates in skin biopsy specimens from study participants during symptomatic herpes simplex virus 2 (HSV-2) reactivation and early healing. Both CD20+ B cells, most of which are antigen inexperienced based on their coexpression of IgD, and ASCs - characterized by dense IgG RNA expression in combination with CD138, IRF4, and Blimp-1 RNA - were found to colocalize with T cells. ASCs clustered with CD4+ T cells, suggesting the potential for crosstalk. HSV-2-specific antibodies to virus surface antigens were also present in tissue and increased in concentration during HSV-2 reactivation and healing, unlike in serum, where concentrations remained static over time. B cells, ASCs, and HSV-specific antibody were rarely detected in biopsies of unaffected skin. Evaluation of samples from serial biopsies demonstrated that B cells and ASCs followed a more migratory than resident pattern of infiltration in HSV-affected genital skin, in contrast to T cells. Together, these observations suggest the presence of distinct phenotypes of B cells in HSV-affected tissue; dissecting their role in reactivation may reveal new therapeutic avenues to control these infections.
Expression of Kisspeptin, Neurokinin B, and Dynorphin During Pubertal Development in Female Sheep
Journal of the Endocrine Society
Aerts, E;Harlow, K;Griesgraber, M;Bowdridge, E;Hardy, S;Nestor, C;Hileman, S;
| DOI: 10.1210/jendso/bvab048.1098
Puberty onset depends upon an increase in pulsatile GnRH/LH secretion, which in sheep is the result of reduced sensitivity to estrogen negative feedback. Neurons within the arcuate nucleus of the hypothalamus (ARC) expressing kisspeptin, neurokinin B (NKB), and dynorphin (i.e. KNDy neurons) express estrogen receptors and are believed to play a key role in mediating the effects of estrogen on GnRH/LH secretion. Therefore, the purpose of this study was to assess changes in kisspeptin, NKB, and dynorphin within the ARC across pubertal development in female sheep. Blood samples were collected at 12-minute intervals for 4 hours and assessed for LH secretion in five age groups of ewes: 5 months (n=6), 6 months (n=6), 7 months (n=5), 8 months (n=5), and 10 months (n=6) of age. Following each bleed, ewes were sacrificed, hypothalamic tissue containing the ARC was collected, and then processed for use in dual immunofluorescence and RNAscope. Mean LH and LH pulse frequencies followed the expected patterns: concentrations and frequencies were low during the prepubertal ages (5-7 months of age), intermediate during the peripubertal age (8 months of age), and elevated in the postpubertal age group (10 months of age). Using immunofluorescence, kisspeptin and NKB immuno-positive cell numbers did not change significantly (P > 0.50) over time with cell numbers averaging 235.3±16.8 and 231.3±16.8, respectively. Colocalization of kisspeptin and NKB was greater than 90% for all age groups. Using RNAscope, the total number of cells expressing mRNA for kisspeptin and dynorphin did not change significantly (P > 0.05) over time with cell numbers averaging 46.7±12.0 and 28.3±10.0 cells/hemisection, respectively. Taken together, our data suggest that the increase in LH secretion that drives puberty onset is not limited by changes in kisspeptin, NKB, or dynorphin expression, but may instead depend on other factors such as changes in receptor expression or changes in KNDy neuron activity via a reduction in inhibitory and/or an increase in stimulatory afferent inputs.
T cells expressing receptor recombination/revision machinery are detected in the tumor microenvironment and expanded in genomically over-unstable models
Cancer immunology research
Morello, G;Cancila, V;La Rosa, M;Germano, G;Lecis, D;Amodio, V;Zanardi, F;Iannelli, F;Greco, D;La Paglia, L;Fiannaca, A;Urso, AM;Graziano, G;Ferrari, F;Sangaletti, S;Pupa, SM;Chiodoni, C;Pruneri, G;Bardelli, A;Colombo, MP;Tripodo, C;
PMID: 33941587 | DOI: 10.1158/2326-6066.CIR-20-0645
Tumors undergo dynamic immunoediting as part of a process that balances immunological sensing of emerging neoantigens and evasion from immune responses. Tumor-infiltrating lymphocytes (TILs) comprise heterogeneous subsets of peripheral T cells characterized by diverse functional differentiation states and dependence on TCR specificity gained through recombination events during their development. We hypothesized that within the tumor microenvironment (TME), an antigenic milieu and immunological interface, tumor-infiltrating peripheral T cells could re-express key elements of the TCR recombination machinery, namely Rag1 and Rag2 recombinases and Tdt polymerase, as a potential mechanism involved in the revision of TCR specificity. Using two syngeneic invasive breast cancer transplantable models, 4T1 and TS/A, we observed Rag1, Rag2, and Dntt in situ mRNA expression characterized rare tumor-infiltrating T cells. In situ expression of the transcripts was increased in co-isogenic Mlh1-deficient tumors, characterized by genomic over-instability, and was also modulated by PD-1 immune checkpoint blockade. Through immunolocalization and mRNA hybridization analyses, we detected the presence of rare TDT+RAG1/2+ cells populating primary tumors and draining lymph nodes in human invasive breast cancer. Analysis of harmonized single-cell RNA-seq datasets of human cancers identified a very small fraction of tumor-associated T cells, characterized by the expression of recombination/revision machinery transcripts, which on pseudotemporal ordering corresponded to differentiated effector T cells. We offer thought-provoking evidence of a TIL microniche marked by rare transcripts involved in TCR shaping.
Thyroid-Like Cholangiocarcinoma: Histopathological, Immunohistochemical, In-Situ Hybridization and Molecular Studies on an Uncommon Emerging Entity
International journal of surgical pathology
Hissong, E;Chiu, K;Park, H;Solomon, J;Song, W;Jessurun, J;
PMID: 33939475 | DOI: 10.1177/10668969211013906
Thyroid-like cholangiocarcinoma is a very uncommon variant of peripheral-type cholangiocarcinoma. To date, only 4 prior cases have been reported. The molecular features of this tumor have not been described. We report a case of a 60-year-old woman with a tumor that evolved over a period of 10 years. A left hepatectomy specimen showed an 11 cm tumor that on histology exhibited areas reminiscent of a thyroid tumor with follicular and insular features which were positive on immunohistochemistry for cytokeratin 7 and in-situ hybridization for albumin. A detailed molecular analysis failed to show mutations common to cholangiocarcinomas but revealed frameshift mutations in 2 chromatin-remodeling genes, CREBBP and KMNT2A. This case confirms that thyroid-like cholangiocarcinoma is a histologic variant of this tumor that is associated with relatively low growth. As most cholangiocarcinomas, it is diffusely positive for cytokeratin 7 and albumin by in-situ hybridization. Given its rarity, the molecular alterations in this specific histologic subtype remain to be fully elucidated.
Transcription factor FOXP2 is a flow-induced regulator of collecting lymphatic vessels
Hernández Vásquez, MN;Ulvmar, MH;González-Loyola, A;Kritikos, I;Sun, Y;He, L;Halin, C;Petrova, TV;Mäkinen, T;
PMID: 33934370 | DOI: 10.15252/embj.2020107192
The lymphatic system is composed of a hierarchical network of fluid absorbing lymphatic capillaries and transporting collecting vessels. Despite distinct functions and morphologies, molecular mechanisms that regulate the identity of the different vessel types are poorly understood. Through transcriptional analysis of murine dermal lymphatic endothelial cells (LECs), we identified Foxp2, a member of the FOXP family of transcription factors implicated in speech development, as a collecting vessel signature gene. FOXP2 expression was induced after initiation of lymph flow in vivo and upon shear stress on primary LECs in vitro. Loss of FOXC2, the major flow-responsive transcriptional regulator of lymphatic valve formation, abolished FOXP2 induction in vitro and in vivo. Genetic deletion of Foxp2 in mice using the endothelial-specific Tie2-Cre or the tamoxifen-inducible LEC-specific Prox1-CreERT2 line resulted in enlarged collecting vessels and defective valves characterized by loss of NFATc1 activity. Our results identify FOXP2 as a new flow-induced transcriptional regulator of collecting lymphatic vessel morphogenesis and highlight the existence of unique transcription factor codes in the establishment of vessel-type-specific endothelial cell identities.