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Bisht S, Singh MF. The triggering pathway, the metabolic amplifying pathway, and cellular transduction in regulation of glucose-dependent biphasic insulin secretion. Arch Physiol Biochem 2024:1-12. [PMID: 38196246 DOI: 10.1080/13813455.2023.2299920] [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] [Received: 08/07/2023] [Accepted: 12/16/2023] [Indexed: 01/11/2024]
Abstract
Introduction: Insulin secretion is a highly regulated process critical for maintaining glucose homeostasis. This abstract explores the intricate interplay between three essential pathways: The Triggering Pathway, The Metabolic Amplifying Pathway, and Cellular Transduction, in orchestrating glucose-dependent biphasic insulin secretion.Mechanism: During the triggering pathway, glucose metabolism in pancreatic beta-cells leads to ATP production, closing ATP-sensitive potassium channels and initiating insulin exocytosis. The metabolic amplifying pathway enhances insulin secretion via key metabolites like NADH and glutamate, enhancing calcium influx and insulin granule exocytosis. Additionally, the cellular transduction pathway involves G-protein coupled receptors and cyclic AMP, modulating insulin secretion.Result and Conclusion: These interconnected pathways ensure a dynamic insulin response to fluctuating glucose levels, with the initial rapid phase and the subsequent sustained phase. Understanding these pathways' complexities provides crucial insights into insulin dysregulation in diabetes and highlights potential therapeutic targets to restore glucose-dependent insulin secretion.
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Affiliation(s)
- Shradha Bisht
- Amity Institute of Pharmacy, Amity University, Lucknow, Uttar Pradesh, India
| | - Mamta F Singh
- School of Pharmaceutical Sciences, SBS University, Balawala, Uttarakhand, India
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Sissaoui S, Cochet M, Poinsot P, Bordat C, Collardeau-Frachon S, Lachaux A, Lacaille F, Peretti N. Lipids Responsible for Intestinal or Hepatic Disorder: When to Suspect a Familial Intestinal Hypocholesterolemia? J Pediatr Gastroenterol Nutr 2021; 73:4-8. [PMID: 33853111 DOI: 10.1097/mpg.0000000000003145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
ABSTRACT Familial intestinal hypocholesterolemias, such as abetalipoproteinemia, hypobetalipoproteinemia, and chylomicron retention disease, are rare genetic diseases that result in a defect in the synthesis or secretion of lipoproteins containing apolipoprotein B.In children, these conditions present with diarrhoea and growth failure, whereas adults present with neuromuscular, ophthalmological, and hepatic symptoms. Simple laboratory investigations have shown that diagnosis can be made from findings of dramatically decreased cholesterol levels, deficiencies in fat-soluble vitamins (mostly vitamin E), endoscopic findings of the characteristic white intestinal mucosa, and fat-loaded enterocytes in biopsy samples. Genetic analysis is used to confirm the diagnosis. Treatment is based on a low-fat diet with essential fatty acid supplementation, high doses of fat-soluble vitamins, and regular and life-long follow-up.The present study examines cases and literature findings of these conditions, and emphasises the need to explore severe hypocholesterolemia and deficiencies in fat-soluble vitamins to not miss these rare, but easy to diagnose and treat, disorders.
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Affiliation(s)
- Samira Sissaoui
- Pediatric Hepatology Unit
- Department of Pediatric Gastroenterology-Hepatology-Nutrition, Reference Center for Biliary Atresia and Genetic Cholestasis, Hôpital Universitaire Necker-Enfants Malades, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris
| | - Manon Cochet
- Pediatric Hepatology Unit
- Department of Pediatric Gastroenterology-Hepatology-Nutrition, Reference Center for Biliary Atresia and Genetic Cholestasis, Hôpital Universitaire Necker-Enfants Malades, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris
| | - Pierre Poinsot
- Univ. Lyon, Hospices Civil de Lyon, Gastro-enterology and Pediatric Nutrition, Reference Center for Intestinal Rare Disease (MaRDi), Hôpital Femme Mere Enfant, Bron
- Univ. Lyon, CarMeN Laboratory, INRAE, UMR1397, INSERM, UMR1060, Pierre-Bénite
| | - Claire Bordat
- Univ. Lyon, CarMeN Laboratory, INRAE, UMR1397, INSERM, UMR1060, Pierre-Bénite
| | - Sophie Collardeau-Frachon
- Univ. Lyon, Hospices Civil de Lyon, Gastro-enterology and Pediatric Nutrition, Reference Center for Intestinal Rare Disease (MaRDi), Hôpital Femme Mere Enfant, Bron
- Univ. Lyon, CarMeN Laboratory, INRAE, UMR1397, INSERM, UMR1060, Pierre-Bénite
- Univ. Lyon, Hospices Civil de Lyon, Institut de pathologie, Groupement Hospitalier Est, Bron, France
| | - Alain Lachaux
- Univ. Lyon, Hospices Civil de Lyon, Gastro-enterology and Pediatric Nutrition, Reference Center for Intestinal Rare Disease (MaRDi), Hôpital Femme Mere Enfant, Bron
- Univ. Lyon, CarMeN Laboratory, INRAE, UMR1397, INSERM, UMR1060, Pierre-Bénite
| | - Florence Lacaille
- Department of Pediatric Gastroenterology-Hepatology-Nutrition, Reference Center for Biliary Atresia and Genetic Cholestasis, Hôpital Universitaire Necker-Enfants Malades, Assistance Publique - Hôpitaux de Paris (AP-HP), Paris
| | - Noël Peretti
- Univ. Lyon, Hospices Civil de Lyon, Gastro-enterology and Pediatric Nutrition, Reference Center for Intestinal Rare Disease (MaRDi), Hôpital Femme Mere Enfant, Bron
- Univ. Lyon, CarMeN Laboratory, INRAE, UMR1397, INSERM, UMR1060, Pierre-Bénite
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In vitro functional characterization of splicing variants of the APOB gene found in familial hypobetalipoproteinemia. J Clin Lipidol 2019; 13:960-969. [PMID: 31629702 DOI: 10.1016/j.jacl.2019.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/22/2019] [Accepted: 09/06/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. OBJECTIVE The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. METHODS ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. RESULTS Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. CONCLUSIONS These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1.
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Rabacchi C, Bigazzi F, Puntoni M, Sbrana F, Sampietro T, Tarugi P, Bertolini S, Calandra S. Phenotypic variability in 4 homozygous familial hypercholesterolemia siblings compound heterozygous for LDLR mutations. J Clin Lipidol 2016; 10:944-952.e1. [DOI: 10.1016/j.jacl.2016.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 12/31/2022]
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