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Teoh CM, Tan SSL, Langenbach SY, Wong AH, Cheong DHJ, Tam JKC, New CS, Tran T. Integrin α7 expression is increased in asthmatic patients and its inhibition reduces Kras protein abundance in airway smooth muscle cells. Sci Rep 2019; 9:9892. [PMID: 31289310 PMCID: PMC6616330 DOI: 10.1038/s41598-019-46260-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/25/2019] [Indexed: 02/07/2023] Open
Abstract
Airway smooth muscle (ASM) cells exhibit plastic phenotypic behavior marked by reversible modulation and maturation between contractile and proliferative phenotypic states. Integrins are a class of transmembrane proteins that have been implicated as novel therapeutic targets for asthma treatment. We previously showed that integrin α7 is a novel marker of the contractile ASM phenotype suggesting that targeting this protein may offer new avenues to counter the increase in ASM cell mass that underlies airways hyperresponsiveness (AHR) in asthma. We now determine whether inhibition of integrin α7 expression would revert ASM cells back to a proliferative phenotype to cause an increase in ASM cell mass. This would be detrimental to asthmatic patients who already exhibit increased ASM mass in their airways. Using immunohistochemical analysis of the Melbourne Epidemiological Study of Childhood Asthma (MESCA) cohort, we show for the first time that integrin α7 expression in patients with severe asthma is increased, supporting a clinically relevant role for this protein in asthma pathophysiology. Moreover, inhibition of the laminin-integrin α7 signaling axis results in a reduction in smooth muscle-alpha actin abundance and does not revert ASM cells back to a proliferative phenotype. We determined that integrin α7-induced Kras isoform of p21 Ras acts as a point of convergence between contractile and proliferative ASM phenotypic states. Our study provides further support for targeting integrin α7 for the development of novel anti-asthma therapies.
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Affiliation(s)
- Chun Ming Teoh
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sheryl S L Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Shenna Y Langenbach
- Department of Pharmacology and Therapeutics, and Lung Health Research Centre, University of Melbourne, Melbourne, Australia
| | - Amanda H Wong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Dorothy H J Cheong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - John K C Tam
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chih Sheng New
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Thai Tran
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Teoh CM, Tan SSL, Tran T. Integrins as Therapeutic Targets for Respiratory Diseases. Curr Mol Med 2016; 15:714-34. [PMID: 26391549 PMCID: PMC5427774 DOI: 10.2174/1566524015666150921105339] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 09/09/2015] [Accepted: 09/19/2015] [Indexed: 01/14/2023]
Abstract
Integrins are a large family of transmembrane heterodimeric proteins that constitute the main receptors for extracellular matrix components. Integrins were initially thought to be primarily involved in the maintenance of cell adhesion and tissue integrity. However, it is now appreciated that integrins play important roles in many other biological processes such as cell survival, proliferation, differentiation, migration, cell shape and polarity. Lung cells express numerous combinations and permutations of integrin heterodimers. The complexity and diversity of different integrin heterodimers being implicated in different lung diseases present a major challenge for drug development. Here we provide a comprehensive overview of the current knowledge of integrins from studies in cell culture to integrin knockout mouse models and provide an update of results from clinical trials for which integrins are therapeutic targets with a focus on respiratory diseases (asthma, emphysema, pneumonia, lung cancer, pulmonary fibrosis and sarcoidosis).
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Affiliation(s)
| | | | - T Tran
- Department of Physiology, MD9, 2 Medical Drive, National University of Singapore, Singapore 117597, Singapore.
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Tran T, Teoh CM, Tam JKC, Qiao Y, Chin CY, Chong OK, Stewart AG, Harris T, Wong WSF, Guan SP, Leung BP, Gerthoffer WT, Unruh H, Halayko AJ. Laminin drives survival signals to promote a contractile smooth muscle phenotype and airway hyperreactivity. FASEB J 2013; 27:3991-4003. [PMID: 23756649 DOI: 10.1096/fj.12-221341] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Increased airway smooth muscle (ASM) mass is believed to underlie the relatively fixed airway hyperresponsiveness (AHR) in asthma. Developments of therapeutic approaches to reverse airway remodeling are impeded by our lack of insight on the mechanisms behind the increase in mass of contractile ASM cells. Increased expression of laminin, an extracellular matrix protein, is associated with asthma. Our studies investigate the role of laminin-induced ASM survival signals in the development of increased ASM and AHR. Antagonizing laminin integrin binding using the laminin-selective competing peptide, YIGSR, and mimicking laminin with exogenous α2-chain laminin, we show that laminin is both necessary and sufficient to induce ASM cell survival, concomitant with the induction of ASM contractile phenotype. Using siRNA, we show that the laminin-binding integrin α7β1 mediates this process. Moreover, in laminin-211-deficient mice, allergen-induced AHR was not observed. Notably, ASM cells from asthmatic airways express a higher abundance of intracellular cell survival proteins, consistent with a role for reduced rates of cell apoptosis in development of ASM hyperplasia. Targeting the laminin-integrin α7β1 signaling pathway may offer new avenues for the development of therapies to reduce the increase in mass of contractile phenotype ASM cells that underlie AHR in asthma.
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Affiliation(s)
- Thai Tran
- 2Department of Physiology, National University of Singapore, Block MD9, 2 Medical Dr., Singapore 117597. E-Mail:
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Teoh CM, Tam JKC, Tran T. Ethical Issues in Using Bronchial Biopsies for Asthma Research. Asian Bioeth Rev 2012. [DOI: 10.1353/asb.2012.0029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Teoh CM, Gunasegaram T, Chan KY, Sukumar N, Sagap I. Review of risk factors associated with the anastomosis leakage in anterior resection in Hospital Universiti Kebangsaan Malaysia. Med J Malaysia 2005; 60:275-80. [PMID: 16379179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
This is a retrospective study evaluating the risk factors for clinical anastomotic leakage after anterior resection in 64 patients with rectal cancer operated from November 2001 till August 2003. The percentage of anastomosis leakage was higher in those patients with diabetic, low albumin level, neoadjuvant radiotherapy, higher staging, and poorly differentiated tumour. However, these differences were statistically not significant. There was a significant difference (p=0.03) of anastomosis leakage in those patients with very distal tumour of < 4cm from anal verge (42%), when compare to those patients with proximal tumor of > 15cm from anal verge (4.3%). The mortality associated with this complication was 30%. Hence, a surgeon may consider a covering stoma or be more vigilant in operating patients with multiple risk factors.
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Affiliation(s)
- C M Teoh
- Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur
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Kalyani A, Teoh CM, Sukumar N. I jejunal patch repair of a duodenal perforation. Med J Malaysia 2005; 60:237-8. [PMID: 16114169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A patient with duodenal ulcer who developed iatrogenic perforation post endoscopy is presente. We present t is case that was treated successfully treated by jejunal serosal patch.
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Affiliation(s)
- A Kalyani
- Department of Surgery, University Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, 56000, Kuala Lumpur
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Chan KY, Teoh CM, Sukumar N. Case report of a difficult venous access: retroperitoneal approach of inserting an improved non-heparinised port for long-term use. Med J Malaysia 2005; 60:94-6. [PMID: 16250289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
This is a case report of a patient with difficult venous access following thrombosis of major superficial and deep veins of the limbs as documented by ultrasound doppler and venography. The insertion of a few central ports were infected and the vein thrombosed. Venography revealed that central venous access was no longer feasible. The previous laparotomies had resulted in dense intra-peritoneal adhesions, and rendered further laparotomy virtually impossible. The patient had occasional adhesion colics, vomiting and hypoglycemic episodes. A rarely performed retro-peritoneal approach of inserting an improved non-heparinised port proved to be effective for long-term management of this patient. The surgical approach and the selected port are discussed.
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Affiliation(s)
- K Y Chan
- Department of Surgery, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, 56000, Kuala Lumpur
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Marjmin O, Badrulhisham B, Teoh CM, Sukumar N, Ahmad Zakuan K. Metastatic cervical carcinoma in the caecum. Med J Malaysia 2005; 60:97-8. [PMID: 16250290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A patient who presented with acute intestinal obstruction had a right hemicolectomy for a caecal tumour. The histopathology report confirmed metastatic carcinoma in the caecum from the cervical carcinoma. Caecum is a very rare site of metastasis from cervical carcinoma. From our literature review, there have been no such cases reported.
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Affiliation(s)
- O Marjmin
- Department of Surgery, Hospital Universiti Kebangsaan Malaysia, Jalan Yaakob Latif, Bandar Tun Razak, 56000, Cheras, Kuala Lumpur
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Sukumar N, Teoh CM. Heterotopic pancreas in the stomach. Med J Malaysia 2004; 59:541-3. [PMID: 15779591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A patient diagnosed with gastrointestinal stromal tumour of the stomach underwent gastrectomy. Post-operatively, histopathology was reported as heterotopic pancreas of the stomach. Heterotopic pancreas is very rare and though most of them appear asymptomatic, surgical resection is advisable.
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Affiliation(s)
- N Sukumar
- Department of Surgery, Hospital University Kebangsaan Malaysia, Jalan Yacob Latif, Bandar Tun Razak, 56000 Kuala Lumpur
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