دانلود مقاله مهار بیان ژن PDHα1 در متابولیسم سلول های کبد چرب
خلاصه
معرفی
مواد و روش ها
نتایج
بحث
نتیجه گیری
منابع مالی
بیانیه هیئت بررسی نهادی
بیانیه رضایت آگاهانه
بیانیه مشارکت نویسنده CRediT
اعلامیه منافع رقابتی
سپاسگزاریها
پیوست A. داده های تکمیلی
در دسترس بودن داده ها
منابع
Abstract
Introduction
Materials and methods
Results
Discussion
Conclusions
Funding
Institutional Review Board Statement
Informed Consent Statement
CRediT authorship contribution statement
Declaration of competing interest
Acknowledgements
Appendix A. Supplementary data
Data availability
References
چکیده
ژن PDHα1 زیرواحد کاتالیزوری PDHE1α کمپلکس پیروات دهیدروژناز (PDH) را کد می کند. بر اساس مطالعات قبلی، این فرضیه وجود دارد که مهار فعالیت PDH از ورود پیروات گلیکولیتیک به چرخه TCA جلوگیری می کند، در حالی که اکسیداسیون اسیدهای چرب را ترویج می کند و سطح تری گلیسیرید کبد (TG) را کاهش می دهد و در نتیجه بیماری کبد چرب غیر الکلی (NAFLD) را کاهش می دهد. در این مطالعه، یک مدل آزمایشگاهی برای NAFLD با امولسیون چربی پزشکی ایجاد شد. موثرترین siRNA برای ژن PDHα1 با فناوری qPCR غربالگری شد. تغییرات در متابولیسم گلوکز و لیپید، و ساختار و عملکرد میتوکندری در سلول های NAFLD در درجه اول پس از انتقال PDHα1 siRNA مورد بررسی قرار گرفت. همانطور که نتایج نشان داد، پس از مهار بیان ژن PDHα1، سطح گلوکز در محیط کشت به طور وابسته به زمان افزایش یافت و فعالیت LDH در سلول‌ها پس از 24 ساعت ترانسفکشن به طور متوسط افزایش یافت و پس از 48 ساعت به سطح طبیعی بازگشت. سطح TG داخل سلولی کاهش یافت در حالی که فعالیت LPS به صورت وابسته به زمان افزایش یافت. هیچ تغییر قابل توجهی در ساختار میتوکندری با یا بدون ترانسفکشن siRNA مشاهده نشد و محتوای ATP به وضوح پس از 24 ساعت ترانسفکشن کاهش یافت و پس از 48 ساعت ترمیم شد. می‌توان نتیجه گرفت که مهار ژن PDHα1 در سلول‌های کبد چرب، تخریب چربی را افزایش می‌دهد و استفاده از گلوکز را تا حدی سرکوب می‌کند، بنابراین سطح TG را بدون تأثیر بر تولید انرژی مورد نیاز برای بقای سلول کاهش می‌دهد.
Abstract
PDHα1 gene encodes catalytic subunit PDHE1α of pyruvate dehydrogenase (PDH) complex. Based on previous studies, it is hypothesized that inhibition of PDH activity prevents the entry of glycolytic pyruvate into TCA cycle, while promotes fatty acid oxidation and reduces liver triglyceride (TG) level, thereby alleviating nonalcoholic fatty liver disease (NAFLD). In this study, an in vitro model for NAFLD was established with medical fat emulsion; the most effective siRNA for PDHα1 gene was screened out by qPCR technology; the alterations in metabolism of glucose and lipid, and structure & function of mitochondria in the NAFLD cells were primarily evaluated after transfecting PDHα1 siRNA. As the results showed, after inhibiting the expression of PDHα1 gene, glucose level in culture medium was time-dependently increased, and LDH activity in the cells was moderately elevated after 24 h of transfection and then returned to the normal level after 48 h; intracellular TG level was decreased while LPS activity was increased in a time-dependent manner; no significant change in mitochondrial structure was observed with or without siRNA transfection, and ATP content was obviously reduced after 24 h of transfection, followed by restoration after 48 h. It can be concluded that inhibiting PDHα1 gene in fatty liver cells enhances lipid degradation, and represses the utilization of glucose to an extent, thus reducing TG level without impacting energy generation required for cell survival.
Introduction
Nonalcoholic fatty liver disease (NAFLD) is a continuous spectrum of diseases characterized by excessive deposition of fat in the liver accompanied with diffuse hepatic cell bullous steatosis caused by the factors other than alcohol and other known liver injury-related factors (Farrell et al., 2007, Targher and Byrne, 2017). In turn, hepatic steatosis further aggravates liver metabolic disorders, or even develops into liver fibrosis and cirrhosis, exacerbating liver damage if not given proper treatment (Monteillet et al., 2018).
Nowadays, it has been widely accepted that intrahepatic lipid accumulation caused by various factors (excessive liver fat synthesis, insulin resistance, inflammation, mitochondrial dysfunction, gut microbiota and adipokines), together with the increased de novo fatty acid synthesis, the reduced fatty acid oxidation (FAO) and the blocked liver lipid efflux ultimately cause the occurrence of fatty liver disease (Ratziu et al., 2016, Matsumoto et al., 2018). Obviously, the formation of fatty liver is closely related with the abnormality of lipid metabolism. Accordingly, how to improve the degradation and transportation of intrahepatic lipid is of great significance in preventing the occurrence of fatty liver. It is noteworthy that mitochondria, also called powerhouses of the cells, play an important role in the regulation of fat metabolism and inflammatory response (Ni et al., 2015). As an example, it has been found that adding MitoQ, one mitochondrial-targeted antioxidant, could strongly rescue mitochondrial function and attenuate the development of fatty liver disease by decreasing pathogenic alterations of cardiolipin content, an unique mitochondrial phospholipid playing a key role in mitochondrial bioenergetics (Fouret et al., 2015).
Conclusions
Based on above findings, inhibiting PDHα1 gene expression could attenuate glucose utilization by the cells, while facilitate lipid degradation which was mainly reflected by the elevated glucose level in the medium and the increased LPS activity, respectively; whereas the cellular energy produced by lipid degradation after interfering the expression of this gene might be not enough to compensate for the decrease of ATP level caused by the reduced glycolysis, which might be the reason for the short-time decrease of energy production.