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Yu B, Lu Q, Li J, Cheng X, Hu H, Li Y, Che T, Hua Y, Jiang H, Zhang Y, Xian C, Yang T, Fu Y, Chen Y, Nan W, McCormick PJ, Xiong B, Duan J, Zeng B, Li Y, Fu Y, Zhang J. Cryo-EM structure of human HCN3 channel and its regulation by cAMP. J Biol Chem 2024; 300:107288. [PMID: 38636662 PMCID: PMC11126801 DOI: 10.1016/j.jbc.2024.107288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 03/30/2024] [Accepted: 04/08/2024] [Indexed: 04/20/2024] Open
Abstract
HCN channels are important for regulating heart rhythm and nerve activity and have been studied as potential drug targets for treating depression, arrhythmia, nerve pain, and epilepsy. Despite possessing unique pharmacological properties, HCN channels share common characteristics in that they are activated by hyperpolarization and modulated by cAMP and other membrane lipids. However, the mechanisms of how these ligands bind and modulate HCN channels are unclear. In this study, we solved structures of full-length human HCN3 using cryo-EM and captured two different states, including a state without any ligand bound and a state with cAMP bound. Our structures reveal the novel binding sites for cholesteryl hemisuccinate in apo state and show how cholesteryl hemisuccinate and cAMP binding cause conformational changes in different states. These findings explain how these small modulators are sensed in mammals at the molecular level. The results of our study could help to design more potent and specific compounds to influence HCN channel activity and offer new therapeutic possibilities for diseases that lack effective treatment.
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Affiliation(s)
- Bo Yu
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qiuyuan Lu
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jian Li
- College of Pharmacy, Gannan Medical University, Ganzhou, China
| | - Xinyu Cheng
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Han Hu
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Yuanshuo Li
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Tong Che
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yaoguang Hua
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Haihai Jiang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yuting Zhang
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Cuiling Xian
- Shenzhen Crystalo Biopharmaceutical Co, Ltd, Shenzhen, Guangdong, China
| | - Tingting Yang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Ying Fu
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yixiang Chen
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Weiwei Nan
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Peter J McCormick
- William Harvey Research Institute, Bart's and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Bing Xiong
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jingjing Duan
- Human Aging Research Institute (HARI), School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yanyan Li
- Department of Chemical Biology, School of Life Southern University of Science and Technology, Southern University of Science and Technology, Shenzhen, Guangdong, China; Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Jin Zhang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China.
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O'Donnell AM. Translational research in Hirschprung's disease at the National Children's Research Centre in Dublin. Pediatr Surg Int 2022; 39:33. [PMID: 36460933 DOI: 10.1007/s00383-022-05323-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/24/2022] [Indexed: 12/04/2022]
Abstract
Hirschsprung's disease (HD) is a congenital condition characterised by aganglionosis in the distal bowel. Over the years, at the National Children's Research Centre (NCRC), HD has been one of the most prominent and successful research areas for Prof. Prem Puri's research team. Research fellows from around the world came to the NCRC to work on both animal and human studies of HD and, cumulatively, made important discoveries in this field, publishing a total of 144 HD articles in peer-reviewed journals. Through their published work, the NCRC has been recognised as the leading international centre for the investigation of HD and its allied disorders. In this review, I will summarise the main findings from this work.
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Choi S, Seo H, Lee K, Shin DH, Wu MJ, Wu W, Huang X, Zhang J, Hong C, Jun JY. Hyperpolarization-activated cyclic nucleotide-gated channels working as pacemaker channels in colonic interstitial cells of Cajal. J Cell Mol Med 2021; 26:364-374. [PMID: 34845842 PMCID: PMC8743669 DOI: 10.1111/jcmm.17087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/28/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
Hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels function as pacemaker channels in spontaneously active cells. We studied the existence of HCN channels and their functional roles in the interstitial cells of Cajal (ICC) from the mouse colon using electrophysiological, immunohistochemical and molecular techniques. HCN1 and HCN3 channels were detected in anoctamin‐1 (Ca2+‐activated Cl− channel; ANO1)‐positive cells within the muscular and myenteric layers in colonic tissues. The mRNA transcripts of HCN1 and HCN3 channels were expressed in ANO1‐positive ICC. In the deletion of HCN1 and HCN3 channels in colonic ICC, the pacemaking potential frequency was reduced. Basal cellular adenylate cyclase activity was decreased by adenylate cyclase inhibitor in colonic ICC, whereas cAMP‐specific phosphodiesterase inhibitors increased it. 8‐Bromo‐cyclic AMP and rolipram increased spontaneous intracellular Ca2+ oscillations. In addition, Ca2+‐dependent adenylate cyclase 1 (AC1) mRNA was detected in colonic ICC. Sulprostone, a PGE2‐EP3 agonist, increased the pacemaking potential frequency, maximum rate of rise of resting membrane in pacemaker potentials and basal cellular adenylate cyclase activity in colonic ICC. These results indicate that HCN channels exist in colonic ICC and participate in generating pacemaking potentials. Thus, HCN channels may be therapeutic targets in disturbed colonic motility disorders.
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Affiliation(s)
- Seok Choi
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Hyunhyo Seo
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Kyungmin Lee
- Department of Anatomy, Brain Science & Engineering Institute, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Dong Hoon Shin
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Mei Jin Wu
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Wenhao Wu
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Xingyou Huang
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Jingwei Zhang
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Chansik Hong
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
| | - Jae Yeoul Jun
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
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Verkuijl SJ, Friedmacher F, Harter PN, Rolle U, Broens PMA. Persistent bowel dysfunction after surgery for Hirschsprung’s disease: A neuropathological perspective. World J Gastrointest Surg 2021; 13:822-833. [PMID: 34512906 PMCID: PMC8394380 DOI: 10.4240/wjgs.v13.i8.822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/12/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023] Open
Abstract
Hirschsprung’s disease (HD) is a congenital disorder, characterized by aganglionosis in the distal part of the gastrointestinal tract. Despite complete surgical resection of the aganglionic segment, both constipation and fecal incontinence persist in a considerable number of patients with limited treatment options. There is growing evidence for structural abnormalities in the ganglionic bowel proximal to the aganglionosis in both humans and animals with HD, which may play a role in persistent bowel dysfunction. These abnormalities include: (1) Histopathological abnormalities of enteric neural cells; (2) Imbalanced expression of neurotransmitters and neuroproteins; (3) Abnormal expression of enteric pacemaker cells; (4) Abnormalities of smooth muscle cells; and (5) Abnormalities within the extracellular matrix. Hence, a better understanding of these previously unrecognized neuropathological abnormalities may improve follow-up and treatment in patients with HD suffering from persistent bowel dysfunction following surgical correction. In the long term, further combination of clinical and neuropathological data will hopefully enable a translational step towards more individual treatment for HD.
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Affiliation(s)
- Sanne J Verkuijl
- Department of Pediatric Surgery, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt 60590, Germany
- Neurological Institute (Edinger-Institute), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt 60528, Germany
- Department of Surgery, Division of Pediatric Surgery, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, Netherlands
| | - Florian Friedmacher
- Department of Pediatric Surgery, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt 60590, Germany
| | - Patrick N Harter
- Neurological Institute (Edinger-Institute), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt 60528, Germany
| | - Udo Rolle
- Department of Pediatric Surgery, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt 60590, Germany
| | - Paul MA Broens
- Department of Surgery, Division of Pediatric Surgery, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, Netherlands
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Benzoni P, Bertoli G, Giannetti F, Piantoni C, Milanesi R, Pecchiari M, Barbuti A, Baruscotti M, Bucchi A. The funny current: Even funnier than 40 years ago. Uncanonical expression and roles of HCN/f channels all over the body. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 166:189-204. [PMID: 34400215 DOI: 10.1016/j.pbiomolbio.2021.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/25/2021] [Accepted: 08/09/2021] [Indexed: 12/25/2022]
Abstract
Discovered some 40 years ago, the If current has since been known as the "pacemaker" current due to its role in the initiation and modulation of the heartbeat and of neuronal excitability. But this is not all, the funny current keeps entertaining the researchers; indeed, several data discovering novel and uncanonical roles of f/HCN channel are quickly accumulating. In the present review, we provide an overview of the expression and cellular functions of HCN/f channels in a variety of systems/organs, and particularly in sour taste transduction, hormones secretion, activation of astrocytes and microglia, inhibition of osteoclastogenesis, renal ammonium excretion, and peristalsis in the gastrointestinal and urine systems. We also analyzed the role of HCN channels in sustaining cellular respiration in mitochondria and their participation to mitophagy under specific conditions. The relevance of HCN currents in undifferentiated cells, and specifically in the control of stem cell cycle and in bioelectrical signals driving left/right asymmetry during zygote development, is also considered. Finally, we present novel data concerning the expression of HCN mRNA in human leukocytes. We can thus conclude that the emerging evidence presented in this review clearly points to an increasing interest and importance of the "funny" current that goes beyond its role in cardiac sinoatrial and neuronal excitability regulation.
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Affiliation(s)
- Patrizia Benzoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Giorgia Bertoli
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Federica Giannetti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Chiara Piantoni
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy; Present Address: Institute of Neurophysiology, Hannover Medical School, Carl-Neuberg-Str.1, 30625, Hannover, Germany
| | - Raffaella Milanesi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy; Present Address: Dipartimento di Medicina Veterinaria, Università degli Studi di Milano, Via Dell'Università 6, 26900, Lodi, Italy
| | - Matteo Pecchiari
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Via L. Mangiagalli 32, 20133, Milan, Italy
| | - Andrea Barbuti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Mirko Baruscotti
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy
| | - Annalisa Bucchi
- The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via G. Celoria 26, 20133, Milan, Italy.
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Kapur RP, Smith C, Ambartsumyan L. Postoperative Pullthrough Obstruction in Hirschsprung Disease: Etiologies and Diagnosis. Pediatr Dev Pathol 2020; 23:40-59. [PMID: 31752599 DOI: 10.1177/1093526619890735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Some patients continue to have obstructive symptoms and/or incontinence after pullthrough surgery for Hirschsprung disease. Incontinence can be due to injury to the anal sphincter and/or dentate line, abnormal colonic motility (nonretentive), or a chronic large stool burden (retentive). A diagnostic algorithm based on clinical and pathological evaluations can be applied to distinguish potential etiologies for obstructive symptoms, which segregate into anatomic (mechanical or histopathological) or physiologic subgroups. Valuable clinical information may be obtained by anorectal examination under anesthesia, radiographic studies, and anorectal or colonic manometry. In addition, histopathological review of a patient's original resection specimen(s) as well as postoperative biopsies of the neorectum usually are an important component of the diagnostic workup. Goals for the surgical pathologist are to exclude incomplete resection of the aganglionic segment or transition zone and to identify other neuromuscular pathology that might explain the patient's dysmotility. Diagnoses established from a combination of clinical and pathological data dramatically alter management strategies. In rare instances, reoperative pullthrough surgery is required, in which case the pathologist must be aware of histopathological features specific to redo pullthrough resection specimens.
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Affiliation(s)
- Raj P Kapur
- Department of Pathology, Seattle Children's Hospital, University of Washington, Seattle, Washington
| | - Caitlin Smith
- Department of Pediatric Surgery, Seattle Children's Hospital, University of Washington, Seattle, Washington
| | - Lusine Ambartsumyan
- Department of Gastroenterology, Seattle Children's Hospital, University of Washington, Seattle, Washington
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Smith C, Ambartsumyan L, Kapur RP. Surgery, Surgical Pathology, and Postoperative Management of Patients With Hirschsprung Disease. Pediatr Dev Pathol 2020; 23:23-39. [PMID: 31747833 DOI: 10.1177/1093526619889436] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Endorectal pullthrough surgery is integral in the treatment of patients with Hirschsprung disease. Several different surgical procedures exist, which share as common goals to excise the aganglionic segment and upstream transition zone and attach ganglionic bowel just proximal to the anal canal. The operation requires collaboration between surgeon and pathologist to localize ganglionic bowel and prevent retention of transition zone. Intraoperative frozen sections are extremely important, first to establish that ganglion cells are present and subsequently to exclude features of transition zone (partial circumferential aganglionosis, myenteric hypoganglionosis, and submucosal nerve hypertrophy) at the proximal surgical (anastomotic) margin. Postoperative histopathological analysis of resection specimens should be tailored to document distal aganglionosis, document the length of the aganglionic segment and its proximity to the anastomotic margin, and confirm that transition zone has been resected completely. Adherence to the recommendations described in this review will reduce the likelihood of transition zone pullthrough and should decrease the incidence of persistent postoperative obstructive symptoms.
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Affiliation(s)
- Caitlin Smith
- Department of Pediatric Surgery, Seattle Children's Hospital and University of Washington, Seattle, Washington
| | - Lusine Ambartsumyan
- Department of Gastroenterology, Seattle Children's Hospital and University of Washington, Seattle, Washington
| | - Raj P Kapur
- Department of Pathology, Seattle Children's Hospital and University of Washington, Seattle, Washington
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Decreased expression of TRAAK channels in Hirschsprung's disease: a possible cause of postoperative dysmotility. Pediatr Surg Int 2019; 35:1431-1435. [PMID: 31542828 DOI: 10.1007/s00383-019-04572-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/12/2019] [Indexed: 12/31/2022]
Abstract
AIM OF THE STUDY Potassium (K+) channels with a two-pore domain (K2P) are a large family of hyperpolarising ion channels which play a key role in cell excitability. This family comprises three members: TREK-1, TREK-2 and TRAAK. TRAAK channels have previously been reported to be expressed in murine enteric ganglia. To date, no data exist regarding TRAAK channel expression in the human colon. Thus, we designed this study to investigate TRAAK gene expression in the normal human colon and in Hirschsprung's disease (HSCR). METHODS HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). qRT-PCR analysis was undertaken to quantify TRAAK gene expression, and immunolabelling of TRAAK proteins was visualized using confocal microscopy. MAIN RESULTS Confocal microscopy revealed TRAAK protein expression within both neurons and interstitial cells of Cajal in the myenteric plexus, with a reduction in both ganglionic HSCR colon and aganglionic HSCR colon, compared to controls. qRT-PCR analysis revealed a significant downregulation of the TRAAK gene in both aganglionic and ganglionic HSCR specimens compared to controls (p < 0.05). CONCLUSIONS TRAAK gene expression is significantly downregulated in HSCR colon, suggesting a role for these ion channels in colonic neurotransmission. TRAAK downregulation within ganglionic specimens highlights the dysfunctional nature of ganglia in this region.
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Abnormal Scn1b and Fxyd1 gene expression in the pulled-through ganglionic colon may influence functional outcome in patients with Hirschsprung's disease. Pediatr Surg Int 2019; 35:9-14. [PMID: 30386899 DOI: 10.1007/s00383-018-4370-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/18/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE Smooth muscle cells are electrically coupled to ICC and PDGFRα+ cells, to regulate smooth muscle contraction. Recent studies have reported that the voltage-gated sodium channel type 1β (Scn1b), and the chloride channel subunit, Fxyd1, are highly expressed by both ICC and PDGFRα+ cells in the mouse colon. We designed this study to investigate the expression of the Scn1b and Fxyd1 genes in the normal human colon and in HSCR. METHODS HSCR tissue specimens (n = 6) were collected at the time of pull-through surgery, while control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 6). qRT-PCR analysis was undertaken to quantify Scn1b and Fxyd1 gene expression, and immunolabelling of Scn1b and Fxyd1 proteins were visualized using confocal microscopy. RESULTS qRT-PCR analysis revealed significant downregulation of Scn1b and Fxyd1 genes in both aganglionic and ganglionic HSCR specimens compared to controls (p < 0.05). Confocal microscopy revealed a reduction in Scn1b and Fxyd1 protein expression in both aganglionic and ganglionic HSCR colon compared to controls. CONCLUSION Scn1b and Fxyd1 expression was significantly downregulated in HSCR colon. These results add to mounting evidence suggesting that the pulled-through ganglionic segment of bowel in these patients is abnormal, despite the presence of ganglion cells.
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Fisher DW, Luu P, Agarwal N, Kurz JE, Chetkovich DM. Loss of HCN2 leads to delayed gastrointestinal motility and reduced energy intake in mice. PLoS One 2018; 13:e0193012. [PMID: 29466436 PMCID: PMC5821371 DOI: 10.1371/journal.pone.0193012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/03/2018] [Indexed: 01/22/2023] Open
Abstract
Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels are important regulators of excitability in neural, cardiac, and other pacemaking cells, which are often altered in disease. In mice, loss of HCN2 leads to cardiac dysrhythmias, persistent spike-wave discharges similar to those seen in absence epilepsy, ataxia, tremor, reduced neuropathic and inflammatory pain, antidepressant-like behavior, infertility, and severely restricted growth. While many of these phenotypes have tissue-specific mechanisms, the cause of restricted growth in HCN2 knockout animals remains unknown. Here, we characterize a novel, 3kb insertion mutation of Hcn2 in the Tremor and Reduced Lifespan 2 (TRLS/2J) mouse that leads to complete loss of HCN2 protein, and we show that this mutation causes many phenotypes similar to other mice lacking HCN2 expression. We then demonstrate that while TRLS/2J mice have low blood glucose levels and impaired growth, dysfunction in hormonal secretion from the pancreas, pituitary, and thyroid are unlikely to lead to this phenotype. Instead, we find that homozygous TRLS/2J mice have abnormal gastrointestinal function that is characterized by less food consumption and delayed gastrointestinal transit as compared to wildtype mice. In summary, a novel mutation in HCN2 likely leads to impaired GI motility, causing the severe growth restriction seen in mice with mutations that eliminate HCN2 expression.
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Affiliation(s)
- Daniel W. Fisher
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Phillip Luu
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Neha Agarwal
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Jonathan E. Kurz
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
| | - Dane M. Chetkovich
- Davee Department of Neurology and Clinical Neurosciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- * E-mail:
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Liu Q, Wu C, Huang S, Wu Q, Zhou T, Liu X, Liu X, Hu X, Li L. Decreased hyperpolarization-activated cyclic nucleotide-gated channels are involved in bladder dysfunction associated with spinal cord injury. Int J Mol Med 2018; 41:2609-2618. [PMID: 29436607 PMCID: PMC5846662 DOI: 10.3892/ijmm.2018.3489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/08/2018] [Indexed: 12/12/2022] Open
Abstract
Spinal cord injury (SCI) leads to bereft voluntary control of bladder, but the possible role of spontaneous excited system in bladder of SCI patients is poorly understood. Hyper polarization-activated cyclic nucleotide-gated (HCN) channels are deemed to regulate the spontaneous contraction of bladder, our study explored the functional role of HCN channels in SCI induced neurogenic bladder. Sixty female Sprague-Dawley rats were randomized into control, sham and SCI groups. Rat models subjected to SCI at S2 levels were successfully established and were assessed using hematoxylin and eosin staining and cystometry. In SCI rats, the mRNA and protein expression levels of HCN channels and the Ih density were significantly reduced, and expression levels of several bladder HCN1 channel regulatory proteins were also significantly changed. The effects of 50 µM forskolin and 50 µM 8-bromoadenosine 3′,5′-cyclic monophosphate on [Ca2+]i of isolated bladder interstitial cells of Cajal-like cells were significantly decreased in SCI rats. The spontaneous contractions in detrusor strips from SCI rats were significantly weakened. Furthermore, detrusor strips from SCI rats exhibited decreased tolerance to two doses of ZD7288 (10 and 50 µM). Taken together, our results indicate that the decreased bladder HCN channel expression and function induced by altered regulatory proteins are involved in the pathological process of SCI induced neurogenic bladder, which present HCN channels as valid therapeutic targets for treating this disease.
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Affiliation(s)
- Qian Liu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Chao Wu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Shengquan Huang
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Qingjian Wu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Tao Zhou
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Xiaobing Liu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Xin Liu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Xiaoyan Hu
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
| | - Longkun Li
- Department of Urology, The Second Affiliated Hospital, The Third Military Medical University, Chongqing 400037, P.R. China
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Liu Q, Long Z, Dong X, Zhang T, Zhao J, Sun B, Zhu J, Li J, Wang Q, Yang Z, Hu X, Li L. Cyclophosphamide-induced HCN1 channel upregulation in interstitial Cajal-like cells leads to bladder hyperactivity in mice. Exp Mol Med 2017; 49:e319. [PMID: 28428632 PMCID: PMC6130216 DOI: 10.1038/emm.2017.31] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 12/20/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are confirmed to be expressed in bladder interstitial Cajal-like cells (ICC-LCs), but little is known about their possible role in cystitis-associated bladder dysfunction. The present study aimed to determine the functional role of HCN channels in regulating bladder function under inflammatory conditions. Sixty female wild-type C57BL/6J mice and sixty female HCN1-knockout mice were randomly assigned to experimental and control groups, respectively. Cyclophosphamide (CYP)-induced cystitis models were successfully established in these mice. CYP treatment significantly enhanced HCN channel protein expression and Ih density and significantly altered bladder HCN1 channel regulatory proteins. Carbachol (CCH) and forskolin (FSK) exerted significant effects on bladder ICC-LC [Ca2+]i in CYP-treated wild-type (WT) mice, and HCN1 channel ablation significantly decreased the effects of CCH and FSK on bladder ICC-LC [Ca2+]i in both naive and CYP-treated mice. CYP treatment significantly potentiated the spontaneous contractions and CCH (0.001–10 μM)-induced phasic contractions of detrusor strips, and HCN1 channel deletion significantly abated such effects. Finally, we demonstrated that the development of CYP-induced bladder overactivity was reversed in HCN1−/− mice. Taken together, our results suggest that CYP-induced enhancements of HCN1 channel expression and function in bladder ICC-LCs are essential for cystitis-associated bladder hyperactivity development, indicating that the HCN1 channel may be a novel therapeutic target for managing bladder hyperactivity.
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Affiliation(s)
- Qian Liu
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Zhou Long
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Xingyou Dong
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Teng Zhang
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Jiang Zhao
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Bishao Sun
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Jingzhen Zhu
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Jia Li
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Qingqing Wang
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Zhenxing Yang
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Xiaoyan Hu
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
| | - Longkun Li
- Department of Urology, Second Affiliated Hospital, Third Military Medical University, Chongqing, China
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Guo T, Li J, Li J, Kong D, Bi C, He Z, Tang D, Jin X, Jin L. Association between hyperpolarization-activated channel in interstitial cells of Cajal and gastrointestinal dysmotility induced by malignant ascites. Oncol Lett 2017; 13:1601-1608. [PMID: 28454297 PMCID: PMC5403200 DOI: 10.3892/ol.2017.5652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/03/2016] [Indexed: 12/20/2022] Open
Abstract
Advanced malignant ascites is accompanied by gastrointestinal dysmotility, and patients often feel abdominal pain, abdominal distention, nausea and constipation. Gastrointestinal dysmotility is not only painful for the patients, but it reduces the absorption of nutrients and affects the physical recovery of patients with malignant ascites. It is reported that changes in interstitial cells of Cajal (ICCs) are responsible for the gastrointestinal dysmotility induced by malignant ascites, but the mechanism is not completely understood. The present study observed a significantly decreased expression of ion channels, including hyperpolarization-activated cyclic nucleotide-gated potassium channel 2 (HCN2) and cyclic adenosine monophosphate, in the condition of malignant ascites. Using electrophysiology, it was identified that malignant ascites led to lower amplitude and slower frequency signals in cells of the small intestine. In addition, when ICCs were cultured with malignant ascites in vitro, the expression of HCN2 of ICCs was significantly reduced, and the data of flow cytometry revealed that the Ca2+ concentration of ICCs was also decreased. The results of electron microscopy analysis demonstrated the nuclei of ICCs were pyknotic, and the processes of ICCs were reduced in malignant ascites. The present study suggests the small intestinal dysmotility caused by malignant ascites may be associated with changes in HCN2 of ICCs, which offers a potential therapeutic target for gastrointestinal dysmotility in advanced malignant ascites.
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Affiliation(s)
- Tieyun Guo
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Jiade Li
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Jing Li
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Dan Kong
- Department of Gynecology, The Third Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Chunli Bi
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Zheng He
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Dai Tang
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Xiaoming Jin
- Department of Pathology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Lianhong Jin
- Department of Histology and Embryology, Basic Medical Science College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
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