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Abstract
Short telomere syndrome is a genetically inherited syndrome resulting in premature telomere shortening. This premature shortening of telomeres can result in hematologic, pulmonary, vascular, gastrointestinal, and hepatic manifestations of disease. Identifying patients with short telomere syndrome can be a clinical challenge due to the multitude of potential manifestations and lack of widely available diagnostic tests. In this review, we will highlight hepatic manifestations of short telomere syndrome with a focus on diagnosis, testing, and potential treatments.
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Affiliation(s)
- Daniel D Penrice
- Department of Internal Medicine, Mayo Clinic Rochester, Rochester, Minnesota
| | - Douglas A Simonetto
- Division of Gastroenterology and Hepatology, Mayo Clinic Rochester, Rochester, Minnesota
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Aramburu T, Plucinsky S, Skordalakes E. POT1-TPP1 telomere length regulation and disease. Comput Struct Biotechnol J 2020; 18:1939-1946. [PMID: 32774788 PMCID: PMC7385035 DOI: 10.1016/j.csbj.2020.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/24/2020] [Accepted: 06/27/2020] [Indexed: 12/27/2022] Open
Abstract
Telomeres are DNA repeats at the ends of linear chromosomes and are replicated by telomerase, a ribonucleoprotein reverse transcriptase. Telomere length regulation and chromosome end capping are essential for genome stability and are mediated primarily by the shelterin and CST complexes. POT1-TPP1, a subunit of shelterin, binds the telomeric overhang, suppresses ATR-dependent DNA damage response, and recruits telomerase to telomeres for DNA replication. POT1 localization to telomeres and chromosome end protection requires its interaction with TPP1. Therefore, the POT1-TPP1 complex is critical to telomere maintenance and full telomerase processivity. The aim of this mini-review is to summarize recent POT1-TPP1 structural studies and discuss how the complex contributes to telomere length regulation. In addition, we review how disruption of POT1-TPP1 function leads to human disease.
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Key Words
- ATM, Ataxia Telangiectasia Mutated protein
- ATR, Ataxia Telangiectasia and Rad3-related Protein
- CST, CTC1, Stn1 and Ten1
- CTC1, Conserved Telomere Capping Protein 1
- POT1
- POT1, Protection of telomere 1
- RAP1, Repressor/Activator Protein 1
- RPA, Replication Protein A
- SMCHD1, Structural Maintenance Of Chromosomes Flexible Hinge Domain Containing 1
- Shelterin
- Stn1, Suppressor of Cdc Thirteen
- TERC, Telomerase RNA
- TERT, Telomerase Reverse Transcriptase
- TIN2, TRF1- and TRF2-Interacting Nuclear Protein 2
- TPP1
- TPP1 also known as ACD, Adrenocortical Dysplasia Protein Homolog
- TRF1, Telomere Repeat binding Factor 1
- TRF2, Telomere Repeat binding Factor 2
- TSPYL5, Testis-specific Y-encoded-like protein 5
- Telomerase
- Telomeres
- Ten1, Telomere Length Regulation Protein
- USP7, ubiquitin-specific-processing protease 7
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Shan L, Liu Z, Ci L, Shuai C, Lv X, Li J. Research progress on the anti-hepatic fibrosis action and mechanism of natural products. Int Immunopharmacol 2019; 75:105765. [PMID: 31336335 DOI: 10.1016/j.intimp.2019.105765] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 07/15/2019] [Indexed: 12/15/2022]
Abstract
Hepatic fibrosis is the most common pathological feature of most chronic liver diseases, and its continuous deterioration gradually develops into liver cirrhosis and eventually leads to liver cancer. At present, there are many kinds of drugs used to treat liver fibrosis. However, Western drugs tend to only target single genes/proteins and induce many adverse reactions. Most of the mechanisms and active ingredients of traditional Chinese medicine (TCM) are not clear, and there is a lack of unified diagnosis and treatment standards. Natural products, which are characterized by structural diversity, low toxicity, and origination from a wide range of sources, have unique advantages and great potential in anti-liver fibrosis. This article summarizes the work done over the previous decade, on the active ingredients in natural products that are reported to have anti-hepatic fibrosis effects. The effective anti-hepatic fibrosis ingredients identified can be generally divided into flavonoids, saponins, polysaccharides and alkaloids. Mechanisms of anti-liver fibrosis include inhibition of liver inflammation, anti-lipid peroxidation injury, inhibition of the activation and proliferation of hepatic stellate cells (HSCs), modulation of the synthesis and secretion of pro-fibrosis factors, and regulation of the synthesis and degradation of the extracellular matrix (ECM). This review provides suggestions for the development of anti-hepatic fibrosis drugs.
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Affiliation(s)
- Liang Shan
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China
| | - Zhenni Liu
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China
| | - Leilei Ci
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China
| | - Chen Shuai
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China
| | - Xiongwen Lv
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China.
| | - Jun Li
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China; The Key laboratory of Anti-inflammatory and Immune medicines, Ministry of Education Hefei, China; Institute for Liver Diseases of Anhui Medical University, Hefei, China
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Abstract
Previous studies have established a correlation between increasing chronological age and risk of cirrhosis. This pattern raised interest in the role of telomeres and the telomerase complex in the pathogenesis of liver fibrosis and cirrhosis. This review aims to summarize and analyze the current understanding of telomere regulation in hepatocytes and lymphocytes and how this ultimately relates to the development of liver fibrosis. Notably, in chronic viral hepatitis, telomere shortening in hepatocytes and lymphocytes occurs in such a way that may promote further viral replication while also leading to liver damage. However, while telomere shortening occurs in both hepatocytes and lymphocytes and ultimately results in cellular death, the mechanisms of telomere loss appear to be initiated by independent processes. The understanding of telomere maintenance on a hepatic and immune system level in both viral and non-viral etiologies of cirrhosis may open doors to novel therapeutic strategies.
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Affiliation(s)
- Abbey Barnard
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA
| | - Ashley Moch
- Department of Surgery, University of California at Los Angeles, Los Angeles, CA, USA
| | - Sammy Saab
- Department of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.,Department of Surgery, University of California at Los Angeles, Los Angeles, CA, USA
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