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Background: Mitral annular calcification (MAC) has been reported as a possible cause of systolic anterior motion (SAM) of the mitral valve and dynamic left ventricular outflow tract (LVOT) obstruction. While morphologic features predisposing to SAM in other clinical settings have been described, patients with MAC+SAM have not been systematically investigated. We hypothesized that bulky calcium deposits in the mitral annulus could displace the valve toward the septum, thus promoting development of SAM., Methods: We studied 30 patients with severe MAC who had SAM with septal contact. Three comparator groups (matched for age and sex) were developed: 30 controls without MAC or SAM, 30 with severe MAC but no SAM, and 30 with SAM but no MAC., Results: Significant differences were found across groups for mitral valve coaptation point-septal distance (CSD), anterior mitral leaflet (AML) length, left ventricular diastolic dimension, and ejection fraction. Comparing all MAC subjects (n = 60) with controls, CSD was less (20.5 ± 4.1 vs 23.2 ± 3.7 mm, P = .003) and ejection fraction was higher (67.7% ± 7.8% vs 60.9% ± 6.4%, P < .0001) in MAC patients. Within MAC subjects AML was longer (21.9 ± 3.0 vs 17.4 ± 2.2 mm, P < .0001) and CSD was smaller (18.0 ± 2.7 vs 23.1 ± 3.6 mm, P < .0001) when SAM was present despite similar height of the calcium bar in the 2 MAC groups (12.4 ± 2.9 vs 11.1 ± 3.1 mm, P = .11). Regression analysis confirmed AML length and CSD as independent predictors of SAM. MAC+SAM patients also had more echocardiographic risk factors for SAM (acute aortomitral angle, small LVOT, long AML, small CSD, and presence of a septal bump) than MAC/no-SAM patients (3.4 ± 0.9 vs 1.8 ± 1.0, P < .0001)., Conclusions: Bulky MAC appears to contribute to dynamic LVOT obstruction when it accumulates in such a way that the mitral valve is displaced anteriorly toward the septum. However, other features are also associated with SAM in these patients, particularly a long AML. A combination of morphologic features and favorable hemodynamics may be needed for SAM to develop in patients with severe MAC., (Copyright © 2022 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Background: Children with exposure to coronavirus disease 2019 in recent times (asymptomatic or symptomatic infection) approaching congenital heart surgery programme are in increasing numbers. Understanding outcomes of such children will help risk-stratify and guide optimisation prior to congenital heart surgery., Objective: The objective of the present study was to determine whether convalescent coronavirus disease 2019 children undergoing congenital heart surgery have any worse mortality or post-operative outcomes., Design: Consecutive children undergoing congenital heart surgery from Oct 2020 to May 2021 were enrolled after testing for reverse transcription-polymerase chain reaction or rapid antigen test and immunoglobulin G antibody prior to surgery. Convalescent coronavirus disease 2019 was defined in any asymptomatic patient positive for immunoglobulin G antibodies and negative for reverse transcription-polymerase chain reaction or rapid antigen test anytime 6 weeks prior to surgery. Control patients were negative for any of the three tests. Mortality and post-operative outcomes were compared among the groups., Results: One thousand one hundred and twenty-nine consecutive congenital heart surgeries were stratified as convalescence and control. Coronavirus disease 2019 Convalescent (n = 349) and coronavirus disease 2019 control (n = 780) groups were comparable for all demographic and clinical factors except younger and smaller kids in control. Convalescent children had no higher mortality, ventilation duration, ICU and hospital stay, no higher support with extracorporeal membrane oxygenation, high flow nasal cannula, no higher need for re-intubations, re-admissions, and no higher infections as central line-associated bloodstream infection, sternal site infection, and ventilator-associated pneumonia on comparison with coronavirus disease 2019 control children., Conclusions: Convalescent coronavirus disease 2019 does not have any unfavourable outcomes as compared to coronavirus disease 2019 control children. Positive immunoglobulin G antibody screening prior to surgery is suggestive of convalescence and supports comparable outcomes on par with control peers.

COVID-19 is a recent pandemic that is still a major health problem of modern times and already more than 17.5 lakhs people succumbed to this deadly disease. This disease is caused by novel coronavirus which is named SARS-COV-2 by the International Committee on Taxonomy of Viruses. This virus originated from Wuhan city in Hubei province of China in December 2019 and within a short period spread across the many countries in the globe. There are a lot of basic as well as clinical research is going on to study the mode of transmission and the mechanism of action of SARS-COV-2 infection and its therapeutics. SARS-COV-2 is not only known to infect lungs, but it also infects other organs in the human body including the gastrointestinal (GI) tract, the liver, and the pancreas via the angiotensin-converting enzyme (ACE) 2, an important component of the renin-angiotensin system. In this short review, we are mainly discussing the mode of SARS-COV-2 transmission, physiological counterbalancing roles of ACE2 and ACE and the tissue patterns of ACE2 expression, and the overall effect of COVID19 on human gastrointestinal System. Therefore, this review sheds light on the possible mechanism of SARS-COV-2 infection in the GI system and its pathological symptoms raising a potential possibility of GI tract acting as a secondary site for SARS-CoV-2 tropism and infection. Finally, future studies to understand the fecal-oral transmission of the virus and the correlation of viral load and severity of GI symptoms are proposed to gain knowledge of the GI symptoms in COVID-19 to aid in early diagnosis and prognosis., Competing Interests: Conflicts of interest Authors do not have any conflicts of interest., (Copyright © 2021 Chang Gung University. All rights reserved.)

Background: Duchenne muscular dystrophy (DMD) is characterized by the lack of dystrophin in skeletal, cardiac, and smooth muscle. Slow colonic transit and constipation are common in DMD patients and animal models of DMD. However, the cause of this hypocontractility and the expression of contractile proteins in smooth muscle are unknown. The aim of the study was to investigate the expression of contractile proteins in the colonic smooth muscle and the function of the colon in control and mdx mice., Methods: Muscle contraction was measured in muscle strips and isolated muscle cells. Peristaltic activity was measured in ex vivo preparations by spatiotemporal mapping, and gastrointestinal (GI) transit in vivo was measured by the distribution of fluorescent marker along the intestine and colon. mRNA expression of contractile proteins smoothelin, caldesmon, calponin, and tropomyosin was measured by qRT-PCR., Results: Expression of mRNA for contractile proteins was decreased in colonic smooth muscle of mdx mice compared with control. Contraction in response to acetylcholine and KCl was decreased in colonic muscle strips and in isolated muscle cells of mdx mice. Distension of ex vivo colons with Krebs buffer induced peristalsis in both control and mdx mice; however, significantly fewer full peristaltic waves were recorded in the colons of mdx mice. GI transit was also inhibited in mdx mice., Conclusion and Inferences: The data indicate that the lack of dystrophin causes decrease in colonic smooth muscle contractility, peristalsis, and GI transit and provides the basis for analysis of mechanisms involved in smooth muscle dysfunction in DMD., (© 2020 John Wiley & Sons Ltd.)

Background: Endoplasmic reticulum (ER) stress is an essential response of epithelial and immune cells to inflammation in Crohn's disease. The presence and mechanisms that might regulate the ER stress response in subepithelial myofibroblasts (SEMFs) and its role in the development of fibrosis in patients with Crohn's disease have not been examined., Methods: Subepithelial myofibroblasts were isolated from the affected ileum and normal ileum of patients with each Montreal phenotype of Crohn's disease and from normal ileum in non-Crohn's subjects. Binding of GRP78 to latent TGF-β1 and its subcellular trafficking was examined using proximity ligation-hybridization assay (PLA). The effects of XBP1 and ATF6 on TGF-β1 expression were measured using DNA-ChIP and luciferase reporter assay. Endoplasmic reticulum stress components, TGF-β1, and collagen levels were analyzed in SEMF transfected with siRNA-mediated knockdown of DNMT1 and GRP78 or with DNMT1 inhibitor 5-Azacytidine or with overexpression of miR-199a-5p., Results: In SEMF of strictured ileum from patients with B2 Crohn's disease, expression of ER stress sensors increased significantly. Tunicamycin elicited time-dependent increase in GRP78 protein levels, direct interaction with latent TGF-β1, and activated TGF-β1 signaling. The TGFB1 DNA-binding activity of ATF-6α and XBP1 were significantly increased and elicited increased TGFB1 transcription in SEMF-isolated from affected ileum. The levels of ER stress components, TGF-β1, and collagen expression in SEMF were significantly decreased following knockdown of DNMT1 or GRP78 by 5-Azacytidine treatment or overexpression of miR-199a-5p., Conclusions: Endoplasmic reticulum stress is present in SEMF of patients susceptible to fibrostenotic Crohn's disease and can contribute to development of fibrosis. Targeting ER stress may represent a novel therapeutic target to prevent fibrosis in patients with fibrostenotic Crohn's disease., (© 2020 Crohn’s & Colitis Foundation. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Justification: A number of guidelines are available for management of congenital heart diseases from infancy to adult life. However, these guidelines are for patients living in high income countries. Separate guidelines, applicable to Indian children, are required when recommending an intervention for congenital heart diseases, as often these patients present late in the course of the disease and may have co-existing morbidities and malnutrition., Process: Guidelines emerged following expert deliberations at the National Consensus Meeting on Management of Congenital Heart Diseases in India, held on 10th and 11th of August 2018 at the All India Institute of Medical Sciences, New Delhi. The meeting was supported by Children's HeartLink, a non-governmental organization based in Minnesota, USA., Objectives: To frame evidence based guidelines for (i) indications and optimal timing of intervention in common congenital heart diseases; (ii) follow-up protocols for patients who have undergone cardiac surgery/catheter interventions for congenital heart diseases., Recommendations: Evidence based recommendations are provided for indications and timing of intervention in common congenital heart diseases, including left-to-right shunts (atrial septal defect, ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus and others), obstructive lesions (pulmonary stenosis, aortic stenosis and coarctation of aorta) and cyanotic congenital heart diseases (tetralogy of Fallot, transposition of great arteries, univentricular hearts, total anomalous pulmonary venous connection, Ebstein anomaly and others). In addition, protocols for follow-up of post surgical patients are also described, disease wise.

Background: l-amino acids, such as monosodium glutamate (MSG), activate the umami receptor T1R1/T1R3. We previously showed increased peristalsis in response to activation of T1R1/T1R3 by MSG in mouse colon. However, the expression and function of these receptors in the different regions of the stomach are not clear., Methods: Mouse gastric smooth muscle cells (SMCs) were isolated and cultured in Dulbecco's Modified Eagle Medium. Expression of T1R1 and T1R3 was measured by RT-PCR and Western blot. The effect of MSG with and without inosine monophosphate (IMP, an allosteric activator of T1R1/T1R3) on acetylcholine (ACh)-induced contraction was measured in muscle strips and isolated SMCs by scanning micrometry. The effect of MSG with or without IMP on activation of G proteins and ACh-induced Ca 2+ release was measured in SMCs., Key Results: Monosodium glutamate inhibited ACh-induced contractions in muscle strips from both antrum and fundus and the effect of MSG was augmented by IMP; the effects were concentration-dependent and not affected by the nitric oxide synthase inhibitor, L-NNA, or tetrodotoxin suggesting a direct effect on SMCs. In isolated gastric SMCs, T1R1 and T1R3 transcripts and protein were identified. Addition of MSG with or without IMP inhibited ACh-induced Ca 2+ release and muscle contraction; the effect on contraction was blocked by pertussis toxin suggesting activation of Gα i proteins. MSG in the presence of IMP selectively activated Gα i2 ., Conclusions and Inferences: Umami receptors (T1R1/T1R3) are present on SMCs of the stomach, and activation of these receptors induces muscle relaxation by decreasing [Ca 2+ ] i via Gα i2 ., (© 2019 John Wiley & Sons Ltd.)

Regulation of gut function depends on the detection and response to luminal contents. Luminal L-amino acids (L-AA) are detected by several receptors including metabotropic glutamate receptors 1 and 4 (mGluR1 and mGluR4), calcium-sensing receptor (CaSR), GPRC family C group 6 subtype A receptor (GPRC6A) and umami taste receptor heterodimer T1R1/T1R3. Here, we show that murine mucosal homogenates and STC-1 cells, a murine enteroendocrine cell line, express mRNA for all L-AA receptors. Immunohistochemical analysis demonstrated the presence of all L-AA receptors on STC-1 with CaSR being most commonly expressed and T1R1 least expressed (35% versus 15% of cells); mGluRs and GPRC6a were intermediate (~ 20% of cells). Regarding coexpression of L-AA receptors, the mGluRs and T1R1 were similarly coexpressed with CaSR (10-12% of cells) whereas GPRC6a was coexpressed least (7% of cells). mGluR1 was coexpressed with GPRC6a in 11% of cells whereas coexpression between other receptors was less (2-8% of cells). CaSR and mGluR1 were coexpressed with glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in 20-25% of cells whereas T1R1 and GPRC6a were coexpressed with GLP-1 and PYY less (8-12% of cells). Only mGluR4 showed differential coexpression with GLP-1 (13%) and PYY (21%). L-Phenylalanine (10 mM) caused a 3-fold increase in GLP-1 release, which was strongly inhibited by siRNA to CaSR indicating functional coupling of CaSR to GLP-1 release. The results suggest that not all STC-1 cells express (and coexpress) L-AA receptors to the same extent and that the pattern of response likely depends on the pattern of expression of L-AA receptors.

A number of guidelines are available for the management of congenital heart diseases (CHD) from infancy to adult life. However, these guidelines are for patients living in high-income countries. Separate guidelines, applicable to Indian children, are required when recommending an intervention for CHD, as often these patients present late in the course of the disease and may have coexisting morbidities and malnutrition. Guidelines emerged following expert deliberations at the National Consensus Meeting on Management of Congenital Heart Diseases in India, held on August 10 and 11, 2018, at the All India Institute of Medical Sciences. The meeting was supported by Children's HeartLink, a nongovernmental organization based in Minnesota, USA. The aim of the study was to frame evidence-based guidelines for (i) indications and optimal timing of intervention in common CHD; (ii) follow-up protocols for patients who have undergone cardiac surgery/catheter interventions for CHD; and (iii) indications for use of pacemakers in children. Evidence-based recommendations are provided for indications and timing of intervention in common CHD, including left-to-right shunts (atrial septal defect, ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus, and others), obstructive lesions (pulmonary stenosis, aortic stenosis, and coarctation of aorta), and cyanotic CHD (tetralogy of Fallot, transposition of great arteries, univentricular hearts, total anomalous pulmonary venous connection, Ebstein's anomaly, and others). In addition, protocols for follow-up of postsurgical patients are also described, disease wise. Guidelines are also given on indications for implantation of permanent pacemakers in children., Competing Interests: There are no conflicts of interest.

Background: Isovaleric acid (IVA) is a 5-carbon branched-chain fatty acid present in fermented foods and produced in the colon by bacterial fermentation of leucine. We previously reported that the shorter, straight-chain fatty acids acetate, propionate and butyrate differentially affect colonic motility; however, the effect of branched-chain fatty acids on gut smooth muscle and motility is unknown., Aims: To determine the effect of IVA on contractility of colonic smooth muscle., Methods: Murine colonic segments were placed in a longitudinal orientation in organ baths in Krebs buffer and fastened to force transducers. Segments were contracted with acetylcholine (ACh), and the effects of IVA on ACh-induced contraction were measured in the absence and presence of tetrodotoxin (TTx) or inhibitors of nitric oxide synthase [L-N-nitroarginine (L-NNA)] or adenylate cyclase (SQ22536). The effect of IVA on ACh-induced contraction was also measured in isolated muscle cells in the presence or absence of SQ22536 or protein kinase A (PKA) inhibitor (H-89). Direct activation of PKA was measured in isolated muscle cells., Results: In colonic segments, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion; the IVA response was not affected by TTx or L-NNA but inhibited by SQ22536. Similarly, in isolated colonic muscle cells, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion and the effect blocked by SQ22536 and H-89. IVA also increased PKA activity in isolated smooth muscle cells., Conclusions: The branched-chain fatty acid IVA acts directly on colonic smooth muscle and causes muscle relaxation via the PKA pathway.

Introduction: A number of guidelines are available for management of congenital heart diseases from infancy to adult life. However, these guidelines are for patients living in high-income countries. Separate guidelines, applicable to Indian children, are required when recommending an intervention for congenital heart diseases, as often these patients present late in the course of the disease and may have co-existing morbidities and malnutrition., Process: Guidelines emerged following expert deliberations at the National Consensus Meeting on Management of Congenital Heart Diseases in India, held on the 10th and 11th of August, 2018 at the All India Institute of Medical Sciences., Objectives: The aim of the study was to frame evidence-based guidelines for (i) indications and optimal timing of intervention in common congenital heart diseases and (ii) follow-up protocols for patients who have undergone cardiac surgery/catheter interventions for congenital heart diseases., Recommendations: Evidence-based recommendations are provided for indications and timing of intervention in common congenital heart diseases, including left-to-right shunts, obstructive lesions, and cyanotic congenital heart diseases. In addition, protocols for follow-up of postsurgical patients are also described., (Copyright © 2019 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

The insulinotropic effects of the incretin hormone, glucagon-like peptide-1 (GLP-1) are mediated via GLP-1 receptors (GLP-1R) present on pancreatic β cells. GLP-1 causes a decrease in the motility of stomach and intestine which involves both central and peripheral nervous systems. The expression and function of GLP-1R in gastrointestinal smooth muscle, however, are not clear. Muscle strips and isolated muscle cells were prepared from mouse colon and the effect of GLP-1(7-36) amide on acetylcholine (ACh)-induced contraction was measured. Muscle cells in culture were used to identify the expression of GLP-1R and the signaling pathways activated by GLP-1(7-36) amide. GLP-1R was expressed in the mucosal and non-mucosal tissue preparations derived from colon, and in smooth muscle cell cultures devoid of other cells such as enteric neurons. In colonic muscle strips, the addition of GLP-1(7-36) amide caused dose-dependent inhibition of acetylcholine-induced contractions. The effect of GLP-1(7-36) amide was partly inhibited by the neuronal blocker tetrodotoxin and nitric oxide (NO) synthase inhibitor l-NNA suggesting both NO-dependent neural and NO-independent direct effects on smooth muscle. In isolated colonic smooth muscle cells, GLP-1(7-36) amide caused an increase in Gα s activity, cAMP levels, and PKA activity, and inhibited ACh-induced contraction. The effect of GLP-1(7-36) amide on Gα s activity and cAMP levels was blocked by NF449, an inhibitor of Gα s, and the effect of GLP-1(7-36) amide on contraction was blocked by NF449 and myristoylated PKI, an inhibitor of PKA. We conclude that colonic smooth muscle cells express GLP-1R, and GLP-1(7-36) amide inhibits acetylcholine-induced contraction via GLP-1R coupled to the Gα s /cAMP/PKA pathway., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Actin polymerization plays an important role in smooth muscle contraction. Integrin-linked kinase (ILK) was shown to mediate actin polymerization in airway smooth muscle. The role of ILK in actin polymerization in response to m2 receptor activation was not in gastric smooth muscle., Methods: Phosphorylation of paxillin, neuronal Wiskott-Aldrich syndrome protein (N-WASp), and association of paxillin with GEF proteins (Cool2/αPix [Cool2/PAK-interacting exchange factor alpha], Cool1/βPix [Cool1/PAK-interacting exchange factor beta], and DOCK 180 [Dedicator of cytokinesis]) and N-WASp with Arp2/3 complex were measured by western blot. Activation of Cdc42 was determined using an antibody for activated Cdc42. Actin polymerization was measured as an increase in F-actin/G-actin ratio., Results: Phosphorylation of paxillin, an association of paxillin with GEF proteins, Cdc42 activity, and actin polymerization were increased in response to m2 receptor activation in gastric smooth muscle cells. The increases in paxillin phosphorylation, Cdc42 activity, and actin polymerization were inhibited by a PI3Kγ inhibitor (AS-605240), ILK siRNA, and ILK dominant negative mutant (ILK [R211]). Increase in actin polymerization was also inhibited by Cdc42 dominant negative mutant (Cdc42 [T17N]). Increases in the association of paxillin with GEF proteins, phosphorylation of N-WASp and its association with Arp2/3 complex were inhibited by ILK (R211)., Conclusion: In gastric smooth muscle cells, activation of PI3Kγ by muscarinic m2 receptors causes ILK-dependent phosphorylation of paxillin, an association of paxillin with Cdc42 GEF proteins and activation of Cdc42, which, in turn, causes phosphorylation of N-WASp and its association with Arp2/3 complex leading to actin polymerization., (© 2018 John Wiley & Sons Ltd.)

In gastrointestinal smooth muscle, acetylcholine induced muscle contraction is biphasic, initial peak followed by sustained contraction. Contraction is regulated by phosphorylation of 20 kDa myosin light chain (MLC) at Ser19, interaction of actin and myosin, and actin polymerization. The present study characterized the signaling mechanisms involved in actin polymerization during initial and sustained muscle contraction in response to muscarinic M3 receptor activation in gastric smooth muscle cells by targeting the effectors of initial (phospholipase C (PLC)-β/Ca2+ pathway) and sustained (RhoA/focal adhesion kinase (FAK)/Rho kinase pathway) contraction. The initial Ca2+ dependent contraction and actin polymerization is mediated by sequential activation of PLC-β1 via Gαq, IP3 formation, Ca2+ release and Ca2+ dependent phosphorylation of proline-rich-tyrosine kinase 2 (Pyk2) at Tyr402. The sustained Ca2+ independent contraction and actin polymerization is mediated by activation of RhoA, and phosphorylation of FAK at Tyr397. Both phosphorylation of Pyk2 and FAK leads to phosphorylation of paxillin at Tyr118 and association of phosphorylated paxillin with the GEF proteins p21-activated kinase (PAK) interacting exchange factor α, β (α and β PIX) and DOCK 180. These GEF proteins stimulate Cdc42 leading to the activation of nucleation promoting factor N-WASP (neuronal Wiskott-Aldrich syndrome protein), which interacts with actin related protein complex 2/3 (Arp2/3) to induce actin polymerization and muscle contraction. Acetylcholine induced muscle contraction is inhibited by actin polymerization inhibitors. Thus, our results suggest that a novel mechanism for the regulation of smooth muscle contraction is mediated by actin polymerization in gastrointestinal smooth muscle which is independent of MLC20 phosphorylation., Competing Interests: The authors have declared that no competing interests exist.

NKX2.5 , a homeobox containing gene, plays an important role in embryonic heart development and associated mutations are linked with various cardiac abnormalities. We sequenced the NKX2.5 gene in 100 congenital heart disease (CHD) patients and 200 controls. Our analysis revealed a total of 7 mutations, 3 in intronic region, 3 in coding region and 1 in 3' UTR. Of the above mutations, one mutation was found to be associated with tetralogy of fallot (TOF) and two (rs2277923 and a novel mutation, D16N) were strongly associated with VSD. A novel missense mutation, D16N (p-value =0.009744), located in the tinman (TN) region and associated with ventricular septal defect (VSD), is the most significant findings of this study. Computational analysis revealed that D16N mutation is pathogenic in nature. Through the molecular modeling, docking and molecular dynamics simulation studies, we have identified the location of mutant D16N in NKX2.5 and its interaction map with other partners at the atomic level. We found NKX2.5-GATA4 complex is stable, however, in case of mutant we observed significant conformational changes and loss of key polar interactions, which might be a cause of the pathogenic behavior. This study underscores the structural basis of D16N pathogenic mutation in the regulation of NKX2.5 and how this mutation renders the structural-functional divergence that possibly leading towards the diseased state., Competing Interests: CONFLICTS OF INTEREST The authors declare that they do not have any conflicts of interest.

Hydrogen sulfide (H 2 S) plays an important role in smooth muscle relaxation. Here, we investigated the expression of enzymes in H 2 S synthesis and the mechanism regulating colonic smooth muscle function by H 2 S. Expression of cystathionine-γ-lyase (CSE), but not cystathionine-β-synthase (CBS), was identified in the colonic smooth muscle of rabbit, mouse, and human. Carbachol (CCh)-induced contraction in rabbit muscle strips and isolated muscle cells was inhibited by l-cysteine (substrate of CSE) and NaHS (an exogenous H 2 S donor) in a concentration-dependent fashion. H 2 S induced S-sulfhydration of RhoA that was associated with inhibition of RhoA activity. CCh-induced Rho kinase activity also was inhibited by l-cysteine and NaHS in a concentration-dependent fashion. Inhibition of CCh-induced contraction by l-cysteine was blocked by the CSE inhibitor, dl-propargylglycine (DL-PPG) in dispersed muscle cells. Inhibition of CCh-induced Rho kinase activity by l-cysteine was blocked by CSE siRNA in cultured cells and DL-PPG in dispersed muscle cells. Stimulation of Rho kinase activity and muscle contraction in response to CCh was also inhibited by l-cysteine or NaHS in colonic muscle cells from mouse and human. Collectively, our studies identified the expression of CSE in colonic smooth muscle and determined that sulfhydration of RhoA by H 2 S leads to inhibition of RhoA and Rho kinase activities and muscle contraction. The mechanism identified may provide novel therapeutic approaches to mitigate gastrointestinal motility disorders., (© 2017 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

Hydrogen sulfide (H 2 S), like nitric oxide (NO), causes smooth muscle relaxation, but unlike NO, does not stimulate soluble guanylyl cyclase (sGC) activity and generate cyclic guanosine 5'-monophosphate (cGMP). The aim of this study was to investigate the interplay between NO and H 2 S in colonic smooth muscle. In colonic smooth muscle from rabbit, mouse, and human, l-cysteine, substrate of cystathionine-γ-lyase (CSE), or NaHS, an H 2 S donor, inhibited phosphodiesterase 5 (PDE5) activity and augmented the increase in cGMP levels, IP 3 receptor phosphorylation at Ser 1756 (measured as a proxy for PKG activation), and muscle relaxation in response to NO donor S- nitrosoglutathione (GSNO), suggesting augmentation of cGMP/PKG pathway by H 2 S. The inhibitory effect of l-cysteine, but not NaHS, on PDE5 activity was blocked in cells transfected with CSE siRNA or treated with CSE inhibitor d,l-propargylglycine (dl-PPG), suggesting activation of CSE and generation of H 2 S in response to l-cysteine. H 2 S levels were increased in response to l-cysteine, and the effect of l-cysteine was augmented by GSNO in a cGMP-dependent protein kinase-sensitive manner, suggesting augmentation of CSE/H 2 S by cGMP/PKG pathway. As a result, GSNO-induced relaxation was inhibited by dl-PPG. In flat-sheet preparation of colon, l-cysteine augmented calcitonin gene-related peptide release in response to mucosal stimulation, and in intact segments, l-cysteine increased the velocity of pellet propulsion. These results demonstrate that in colonic smooth muscle, there is a novel interplay between NO and H 2 S. NO generates H 2 S via cGMP/PKG pathway, and H 2 S, in turn, inhibits PDE5 activity and augments NO-induced cGMP levels. In the intact colon, H 2 S promotes colonic transit. NEW & NOTEWORTHY Hydrogen sulfide (H 2 S) and nitric oxide (NO) are important regulators of gastrointestinal motility. The studies herein provide the cross talk between NO and H 2 S signaling to mediate smooth muscle relaxation and colonic transit. H 2 S inhibits phosphodiesterase 5 activity to augment cGMP levels in response to NO, which, in turn, via cGMP/PKG pathway, generates H 2 S. These studies suggest that interventions targeted at restoring NO and H 2 S homeostasis within the smooth muscle may provide novel therapeutic approaches to mitigate motility disorders., (Copyright © 2017 the American Physiological Society.)

Background: The pathophysiology of increased severity of erectile dysfunction in men with diabetes and their poor response to oral pharmacotherapy are unclear. Defective vascular endothelium and consequent impairment in the formation and action of nitric oxide (NO) are implicated as potential mechanisms. Endothelial NO synthase, critical for NO generation, is localized to caveolae, plasma membrane lipid rafts enriched in structural proteins, and caveolins. Type 2 diabetes mellitus (T2DM)-induced changes in caveolin expression are recognized to play a role in cardiovascular dysfunction., Aims: To evaluate DM-related changes to male erectile tissue in a mouse model that closely resembles human T2DM and study the specific role of caveolins in penile blood flow and microvascular perfusion using mice lacking caveolin (Cav)-1 or Cav-3., Methods: We used wild-type C57BL6 (control) and Cav-1 and Cav-3 knockout (KO) male mice. T2DM was induced by streptozotocin followed by a high-fat diet for 4 months. Penile expressions of Cav-1, Cav-3, and endothelial NO synthase were determined by western blot, and phosphodiesterase type 5 activity was measured using [ 3 H] cyclic guanosine monophosphate as a substrate. For hemodynamic studies, Cav-1 and Cav-3 KO mice were anesthetized, and penile blood flow (peak systolic velocity and end-diastolic velocity; millimeters per second) was determined using a high-frequency and high-resolution digital imaging color Doppler system. Penile tissue microcirculatory blood perfusion (arbitrary perfusion units) was measured using a novel PeriCam PSI system., Outcomes: Penile erectile tissues were harvested for histologic studies to assess Cav-1, Cav-3, and endothelial NO synthase expression, phosphodiesterase type 5 activity, and blood flow, and perfusion measurements were assessed for hemodynamic studies before and after an intracavernosal injection of prostaglandin E 1 (50 ng)., Results: In T2DM mice, decreased Cav-1 and Cav-3 penile protein expression and increased phosphodiesterase type 5 activity were observed. Decreased response to prostaglandin E 1 in peak systolic velocity (33 ± 4 mm/s in Cav-1 KO mice vs 62 ± 5 mm/s in control mice) and perfusion (146 ± 12 AU in Cav-1 KO mice vs 256 ± 12 AU in control mice) was observed. Hemodynamic changes in Cav-3 KO mice were insignificant., Clinical Translation: Our findings provide novel mechanistic insights into erectile dysfunction severity and poor pharmacotherapy that could have potential application to patients with T2DM., Strengths and Limitations: Use of KO mice and novel hemodynamic techniques are the strengths. A limitation is the lack of direct evaluation of penile hemodynamics in T2DM mice., Conclusion: Altered penile Cav-1 expression in T2DM mice and impaired penile hemodynamics in Cav-1 KO mice suggests a regulatory role for Cav-1 in DM-related erectile dysfunction. Parikh J, Zemljic-Harpf A, Fu J, et al. Altered Penile Caveolin Expression in Diabetes: Potential Role in Erectile Dysfunction. J Sex Med 2017;14:1177-1186., (Published by Elsevier Inc.)

The pathogenesis of diabetes-associated motility disorders are multifactorial and attributed to abnormalities in extrinsic and intrinsic innervation, and a decrease in the number of interstitial cells of Cajal, and nNOS expression and activity. Here we studied the effect of hyperglycemia on smooth muscle function. Using smooth muscles from the fundus of ob/ob mice and of wild type (WT) mice treated with 30 mM glucose (HG), we identified the molecular mechanism by which hyperglycemia upregulates RhoA/Rho kinase pathway and muscle contraction. RhoA expression, Rho kinase activity and muscle contraction were increased, while miR-133a expression was decreased in smooth muscle of ob/ob mice and in smooth muscle treated with HG. Intraperitoneal injections of pre-miR-133a decreased RhoA expression in WT mice and reversed the increase in RhoA expression in ob/ob mice. Intraperitoneal injections of antagomiR-133a increased RhoA expression in WT mice and augmented the increase in RhoA expression in ob/ob mice. The effect of pre-miR-133a or antagomiR-133a in vitro in smooth muscle treated with HG was similar to that obtained in vivo, suggesting that the expression of RhoA is negatively regulated by miR-133a and a decrease in miR-133a expression in diabetes causes an increase in RhoA expression. Oxidative stress (levels of reactive oxygen species and hydrogen peroxide, and expression of superoxide dismutase 1 and NADPH oxidase 4) was increased in smooth muscle of ob/ob mice and in HG-treated smooth muscle. Treatment of ob/ob mice with N-acetylcysteine (NAC) in vivo or addition of NAC in vitro to HG-treated smooth muscle reversed the effect of glucose on the expression of miR-133a and RhoA, Rho kinase activity and muscle contraction. NAC treatment also reversed the decrease in gastric emptying in ob/ob mice. We conclude that oxidative stress in diabetes causes a decrease in miR-133a expression leading to an increase in RhoA/Rho kinase pathway and muscle contraction.

During postnatal development rats demonstrate an age-dependent increase in NaCl chorda tympani (CT) responses and the number of functional apical amiloride-sensitive epithelial Na+ channels (ENaCs) in salt sensing fungiform (FF) taste receptor cells (TRCs). Currently, the intracellular signals that regulate the postnatal development of salt taste have not been identified. We investigated the effect of cAMP, a downstream signal for arginine vasopressin (AVP) action, on the postnatal development of NaCl responses in 19-23 day old rats. ENaC-dependent NaCl CT responses were monitored after lingual application of 8-chlorophenylthio-cAMP (8-CPT-cAMP) under open-circuit conditions and under ±60 mV lingual voltage clamp. Behavioral responses were tested using 2 bottle/24h NaCl preference tests. The effect of [deamino-Cys1, D-Arg8]-vasopressin (dDAVP, a specific V2R agonist) was investigated on ENaC subunit trafficking in rat FF TRCs and on cAMP generation in cultured adult human FF taste cells (HBO cells). Our results show that in 19-23 day old rats, the ENaC-dependent maximum NaCl CT response was a saturating sigmoidal function of 8-CPT-cAMP concentration. 8-CPT-cAMP increased the voltage-sensitivity of the NaCl CT response and the apical Na+ response conductance. Intravenous injections of dDAVP increased ENaC expression and γ-ENaC trafficking from cytosolic compartment to the apical compartment in rat FF TRCs. In HBO cells dDAVP increased intracellular cAMP and cAMP increased trafficking of γ- and δ-ENaC from cytosolic compartment to the apical compartment 10 min post-cAMP treatment. Control 19-23 day old rats were indifferent to NaCl, but showed clear preference for appetitive NaCl concentrations after 8-CPT-cAMP treatment. Relative to adult rats, 14 day old rats demonstrated significantly less V2R antibody binding in circumvallate TRCs. We conclude that an age-dependent increase in V2R expression produces an AVP-induced incremental increase in cAMP that modulates the postnatal increase in TRC ENaC and the neural and behavioral responses to NaCl., Competing Interests: The authors have declared that no competing interests exist.

GATA transcription factors regulate an array of genes important in cell proliferation and differentiation. Here we report the identification of regulator of G protein signaling 4 (RGS4) as a novel target for GATA-6 transcription factor. Although three sites (a, b, c) within the proximal region of rabbit RGS4 promoter for GATA transcription factors were predicted by bioinformatics analysis, only GATA-a site (16 bp from the core TATA box) is essential for RGS4 transcriptional regulation. RT-PCR analysis demonstrated that only GATA-6 was highly expressed in rabbit colonic smooth muscle cells but GATA-4/6 were expressed in cardiac myocytes and GATA-1/2/3 expressed in blood cells. Adenovirus-mediated expression of GATA-6 but not GATA-1 significantly increased the constitutive and IL-1β-induced mRNA expression of the endogenous RGS4 in colonic smooth muscle cells. IL-1β stimulation induced GATA-6 nuclear translocation and increased GATA-6 binding to RGS4 promoter. These data suggest that GATA factor could affect G protein signaling through regulating RGS4 expression, and GATA signaling may develop as a future therapeutic target for RGS4-related diseases., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In addition to the T2R bitter taste receptors, neuronal nicotinic acetylcholine receptors (nAChRs) have recently been shown to be involved in the bitter taste transduction of nicotine, acetylcholine and ethanol. However, at present it is not clear if nAChRs are expressed in enteroendocrine cells other than beta cells of the pancreas and enterochromaffin cells, and if they play a role in the synthesis and release of neurohumoral peptides. Accordingly, we investigated the expression and functional role of nAChRs in enteroendocrine STC-1 cells. Our studies using RT-PCR, qRT-PCR, immunohistochemical and Western blotting techniques demonstrate that STC-1 cells express several α and β nAChR subunits. Exposing STC-1 cells to nicotine acutely (24h) or chronically (4 days) induced a differential increase in the expression of nAChR subunit mRNA and protein in a dose- and time-dependent fashion. Mecamylamine, a non-selective antagonist of nAChRs, inhibited the nicotine-induced increase in mRNA expression of nAChRs. Exposing STC-1 cells to nicotine increased intracellular Ca2+ in a dose-dependent manner that was inhibited in the presence of mecamylamine or dihydro-β-erythroidine, a α4β2 nAChR antagonist. Brain-derived neurotrophic factor (BDNF) mRNA and protein were detected in STC-1 cells using RT-PCR, specific BDNF antibody, and enzyme-linked immunosorbent assay. Acute nicotine exposure (30 min) decreased the cellular content of BDNF in STC-1 cells. The nicotine-induced decrease in BDNF was inhibited in the presence of mecamylamine. We also detected α3 and β4 mRNA in intestinal mucosal cells and α3 protein expression in intestinal enteroendocrine cells. We conclude that STC-1 cells and intestinal enteroendocrine cells express nAChRs. In STC-1 cells nAChR expression is modulated by exposure to nicotine in a dose- and time-dependent manner. Nicotine interacts with nAChRs and inhibits BDNF expression in STC-1 cells., Competing Interests: The authors have declared that no competing interests exist.

Background & Objectives: Dilated cardiomyopathy (DCM) is a progressive disease of heart with systolic and diastolic dysfunction carrying a poor long-term prognosis. The prognostic index and predictors of mortality are considered to be useful in guiding the treatment. This study was undertaken to evaluate the effects of hypertension at presentation on prognosis in patients with DCM presenting with normal renal and coronary angiogram., Methods: An observational, analytical, non-interventional and a combination of retrospective and prospective study was conducted in patients between 15 and 75 yr of age with DCM having on and off symptoms while receiving treatment in a cardiology outpatient department for more than a year. Sixty patients who fulfilled the inclusion criteria were enrolled in the study. Left ventricular systolic and diastolic functions were assessed by echocardiography along with New York Heart Association (NYHA) functional class prospectively and at baseline retrospectively. Patients were grouped into two categories: DCM with hypertension at presentation (HTNAP, Category 1) and DCM without hypertension at presentation (NHTNAP, Category 2). The primary end-points were the number and dose of parenteral drugs at hospitalization, duration of hospital stay and change in the left ventricular (LV) systolic function expressed as LV ejection fraction, and the secondary end-points included overall mortality, change in LV and right ventricular systolic and diastolic functions and change in the NYHA functional class between baseline and three month follow up in patients., Results: Thirty five and 25 patients presented with HTNAP and NHTNAP, respectively (total 60). The overall mortality was 10 per cent (6/60). The number of hospitalizations was less in HTNAP category and of days of hospital stay was 6.3 in HTNAP and 9.8 in NHTNAP, the difference being significant (P < 0.001). The HTNAP category required less parenteral diuretics and inotropes compared with the NHTNAP category. The echocardiographic parameters showed better improvements in the HTNAP group as compared to the NHTNAP group. Overall, the patients in the <35 yr of age showed the best prognosis (P < 0.001)., Interpretation & Conclusions: Normal or high blood pressure response at acute presentation of DCM leads to better prognosis which may be due to an intact renovascular and an active sympathetic system and can depict the stage of DCM., Competing Interests: None.