Влияние дексаметазона на экспрессию и содержание гликозилированных компонентов в ткани головного мозга мышей

Introduction. Glucocorticoids are actively used in the treatment of various diseases, however their long-term use leads to numerous negative side-effects, the molecular mechanisms of which remain poorly understood.Aim. Study of the short-term (1–10 days) effects of various doses of dexamethasone (Dex) (0,1–10 mg/kg) on the expression of the glucocorticoid receptor (GR, Nr3c1), core proteins of main proteoglycans and heparan sulfate metabolism-involved genes, as well as the content of carbohydrate macromolecules of glycosaminoglycans in the brain tissue of experimental animals.Materials and methods. In the study, C57Bl/6 mice were used. The expression of GR, proteoglycan core proteins and heparan sulfate metabolism-involved genes was determined by real-time polymerase chain reaction with reverse transcription. The content and localization of GR protein molecule were studied by Western blot and immunohistochemical analysis, and the glycosaminoglycan content was determined by dot-blot analysis and Alcian Blue staining.Results. It was shown that a single Dex administration leads to fast (1–3 days) short-term activation of GR expression (+1.5 times, p <0.05), proteoglycan’s genes (syndecan-3, Sdc3; perlecan, Hspg2; phosphacan, Ptprz1; neurocan, Ncan; +2–3-fold; p <0.05) and heparan sulfate-metabolism-involved genes (Ndst1, Glce, Hs2st1, Hs6st1, Sulf1 / 2; +1.5–2-fold; p <0.05) in the mouse brain, with a return to control values by 7–10 days after Dex administration. At the same time, the effect of Dex on carbohydrate macromolecules of glycosaminoglycans was more delayed and stable, increasing the content of low-sulfated glycosaminoglycans in the brain tissue in a dose-dependent manner starting from day 1 after Dex administration. Highly-sulfated glycosaminoglycans showed more delayed response to Dex administration, and an increase in their content was observed only at higher doses (2.5 and 10 mg/kg) and only on 7–10 days after its administration, apparently, mainly due to an increase in heparan sulfate content.Conclusion. In general, the effect of a single injection of Dex on the transcriptional activity of GR, proteoglycan core proteins and heparan sulfate metabolism-involved genes were short-termed, and the genes expression quickly returned to the normal levels. However, even a single use of Dex significantly increased the content of total as well as highly sulfated glycosaminoglycans in the mouse brain tissue, which can lead to the changes in the composition and structure of the brain tissue, as well as its functional characteristics.Введение. Глюкокортикоиды активно используются при лечении различных заболеваний, однако их длительное применение приводит ко множеству побочных эффектов, молекулярные механизмы развития которых остаются недостаточно изученными.Цель исследования – изучение краткосрочного (1–10 сут) влияния различных доз дексаметазона (Dex) (0,1–10 мг/кг) на экспрессию глюкокортикоидного рецептора (GR, Nr3c1), коровых белков основных протеогликанов и ферментов биосинтеза углеводных цепей гепарансульфата, а также содержание углеводных макромолекул гликозаминогликанов в ткани головного мозга экспериментальных животных.Материалы и методы. В исследовании использовали мышей линии C57Bl/6. Экспрессию GR, коровых белков протеогликанов и генов, кодирующих ферменты биосинтеза гепарансульфата, определяли с помощью полимеразной цепной реакции с обратной транскрипцией в реальном времени. Содержание и локализация белковой молекулы GR были изучены методами Вестерн-блоттинга и иммуногистохимического анализа, а содержание гликозаминогликанов – с помощью дот-блот анализа и окраски альциановым синим.Результаты. Было показано, что однократное введение Dex приводило к быстрой (на 1–3-и сутки) кратковременной активации экспрессии GR (+1,5 раза; p <0,05) некоторых генов коровых белков протеогликанов (синдекан-3, Sdc3; перлекан, Hspg2; фосфакан, Ptprz1; нейрокан, Ncan; +2–3 раза; p <0,05) и генов ферментов биосинтеза гепарансульфатов (Ndst1, Glce, Hs2st1, Hs6st1, Sulf1 / 2; +1,5–2 раза; p <0,05) в мозге мышей с возвращением к контрольным показателям к 7–10-м суткам после введения Dex. При этом влияние данного препарата на углеводные макромолекулы гликозаминогликанов имело более отсроченный и стабильный характер, дозозависимо увеличивая содержание общих гликозаминогликанов в ткани мозга, начиная с 1-х суток после введения Dex. Высокосульфатированные гликозаминогликаны демонстрировали более медленный ответ на введение препарата, повышение их содержания наблюдалось только при более высоких дозах (2,5 и 10 мг/кг) и только на 7–10-е сутки после его введения в основном за счет повышения содержания гепарансульфата.Заключение. Влияние однократного применения Dex на транскрипционную активность GR, протеогликанов и ферментов биосинтеза гепарансульфата носит кратковременный характер, и экспрессия генов быстро возвращается к нормальному уровню. Однако даже однократное применение Dex значительно повышает содержание общих и высокосульфатированных гликозаминогликанов в ткани головного мозга мышей, что может привести к изменению состава и структуры ткани головного мозга, а также его функциональных характеристик

LGR6 Is a High Affinity Receptor of R-Spondins and Potentially Functions as a Tumor Suppressor

BACKGROUND: LGR6 (leucine-rich repeat containing, G protein-coupled receptor 6) is a member of the rhodopsin-like seven transmembrane domain receptor superfamily with the highest homology to LGR4 and LGR5. LGR6 was found as one of the novel genes mutated in colon cancer through total exon sequencing and its promoter region is hypermethylated in 20-50% of colon cancer cases. In the skin, LGR6 marks a population of stem cells that can give rise to all cell lineages. Recently, we and others demonstrated that LGR4 and LGR5 function as receptors of R-spondins to potentiate Wnt/β-catenin signaling. However, the binding affinity and functional response of LGR6 to R-spondins, and the activity of colon cancer mutants of LGR6 have not been determined. PRINCIPAL FINDINGS: We found that LGR6 also binds and responds to R-spondins 1-3 with high affinity to enhance Wnt/β-catenin signaling through increased LRP6 phosphorylation. Similar to LGR4 and LGR5, LGR6 is not coupled to heterotrimeric G proteins or to β-arrestin following R-spondin stimulation. Functional and expression analysis of three somatic mutations identified in colon cancer samples indicates that one mutant fails to bind and respond to R-spondin (loss-of-function), but the other two have no significant effect on receptor function. Overexpression of wild-type LGR6 in HeLa cells leads to increased cell migration following co-treatment with R-spondin1 and Wnt3a when compared to vector control cells or cells overexpressing the loss-of-function mutant. CONCLUSIONS: LGR6 is a high affinity receptor for R-spondins 1-3 and potentially functions as a tumor suppressor despite its positive effect on Wnt/β-catenin signaling

RSPO3 impacts body fat distribution and regulates adipose cell biology in vitro

Fat distribution is an independent cardiometabolic risk factor. However, its molecular and cellular underpinnings remain obscure. Here we demonstrate that two independent GWAS signals at RSPO3, which are associated with increased body mass index-adjusted waist-to-hip ratio, act to specifically increase RSPO3 expression in subcutaneous adipocytes. These variants are also associated with reduced lower-body fat, enlarged gluteal adipocytes and insulin resistance. Based on human cellular studies RSPO3 may limit gluteofemoral adipose tissue (AT) expansion by suppressing adipogenesis and increasing gluteal adipocyte susceptibility to apoptosis. RSPO3 may also promote upper-body fat distribution by stimulating abdominal adipose progenitor (AP) proliferation. The distinct biological responses elicited by RSPO3 in abdominal versus gluteal APs in vitro are associated with differential changes in WNT signalling. Zebrafish carrying a nonsense rspo3 mutation display altered fat distribution. Our study identifies RSPO3 as an important determinant of peripheral AT storage capacity

Prospects for the development of hypospadiology

On the basis of follow-up studies on 1584 patients with hypospadias identified key points in the treatment of such patients. Data cited in the article indicate that the currently accepted methods of forming the head of the penis do not match the normal anatomy of the head. The paper analyzes the techniques of straightening the penis and causes the formation of skin and urethral fistulas. To improve the results of treatment of the proposed new operational solutions