scholarly journals Galanin inhibits leptin expression and secretion in rat adipose tissue and 3T3-L1 adipocytes

2004 ◽  
Vol 33 (1) ◽  
pp. 11-19 ◽  
Author(s):  
RY Li ◽  
HD Song ◽  
WJ Shi ◽  
SM Hu ◽  
YS Yang ◽  
...  

In addition to serving as a fat depot, adipose tissue is also considered as an important endocrine organ that synthesizes and secretes a number of factors. Leptin is an adipocyte-derived hormone that plays a vital role in energy balance. Expression of leptin is regulated by dietary status and hormones. In the present study, we report that galanin, an orexigenic peptide, inhibits leptin expression and secretion in rat adipose tissue and in 3T3-L1 adipocytes. Treatment with galanin (25 micro g/animal) induced approximately 46% down-regulation of leptin secretion at 15 min, followed by 40, 37 and 47% decreases in leptin secretion at 1, 2 and 4 h respectively. Although Northern blot analysis of adipose tissue from the same animals showed that leptin mRNA expression in adipose tissue was unaffected by galanin treatment for 2 h, galanin treatment for 4 h led to decline of leptin mRNA expression in a dose-dependent manner. Meanwhile, treating the rats with galanin had no effect on leptin mRNA expression in the hypothalamus. The inhibitory action of the galanin on leptin mRNA and protein levels was also observed in vitro. When incubated with 10 nM galanin for 48 h, leptin mRNA expression and protein secretion also decreased in 3T3-L1 adipocytes. On the other hand, galanin was found not only to express in rat adipose tissue, but also to increase about 8-fold after fasting. Based on these data, we speculate that increased galanin expression in rat adipose tissue after fasting may be involved in reducing leptin expression and secretion in fasting rats.

1993 ◽  
Vol 293 (3) ◽  
pp. 807-812 ◽  
Author(s):  
Y Kamei ◽  
T Kawada ◽  
R Kazuki ◽  
E Sugimoto

Retinoids, especially all-trans retinoic acid (RA), have been shown to inhibit the differentiation of preadipose cells. In the present study, the expression of retinoic acid receptors (RAR alpha, beta and gamma) and retinoid X receptors (RXR alpha, beta and gamma) was examined by Northern blot analysis in rat adipose tissue and mouse 3T3-L1 adipose cells. The adipose tissue and/or 3T3-L1 cells expressed mRNAs for a number of nuclear retinoid receptors, including RAR alpha, beta and gamma, and RXR alpha, beta and gamma. RAR alpha, RAR gamma, RXR alpha and RXR beta mRNAs were abundant in adipose tissue and 3T3-L1 cells. RXR gamma mRNA was detected in adipose tissue but not in 3T3-L1 cells. Treatment of 3T3-L1 cells with 1 microM RA led to a 4-5-fold increase in the RAR gamma mRNA level, but only a trace amount of RAR beta mRNA was detected. RAR gamma mRNA expression was rapidly (within 2 h) induced by physiological concentrations of RA in a dose-dependent manner. The response of RAR gamma mRNA expression to RA was reversible; rapid disappearance of RAR gamma mRNA occurred on RA removal. In addition, the induction of RAR gamma expression did not require de novo protein synthesis, but was completely abolished by an inhibitor of RNA synthesis. Using RAR gamma 1 and gamma 2 isoform-specific probes, the patterns of RAR gamma 1 and gamma 2 mRNA expression in 3T3-L1 cells in the presence and absence of RA were examined. RAR gamma 1 mRNA was detected in 3T3-L1 cells but was not affected by RA treatment; however, RAR gamma 2 mRNA was strongly induced by RA.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e13560-e13560
Author(s):  
Dorothee Gramatzki ◽  
Emese Szabo ◽  
Martin Gramatzki ◽  
Matthias Peipp ◽  
Michael Weller

e13560 Background: Glioblastoma is the most common primary malignant brain tumor with a poor prognosis. CD317 (HM1.24) is a transmembrane protein and may exist in differently spliced variants. It is highly expressed on plasma cells in multiple myeloma, as well as in certain solid tumor types. While several antibody drug conjugates are already in clinical practice, small immunotoxins with a different intracellular mode of action are only established in hairy cell leukemia. The immunotoxin HM1.24-ETA’ protein is a CD317 single chain Fv (scFv) antibody fused to a truncated version of Pseudomonas aeruginosa exotoxin A (ETA’). Methods: In vivo CD317 mRNA expression in human glioma of different grades and survival probabilities of glioblastoma patients based on CD317 mRNA expression were analyzed using the database of the Cancer Genome Atlas network (TCGA). CD317 protein expression was analyzed by immunohistochemistry in a human tissue microarray (TMA). In vitro CD317 mRNA expression was assessed by RT-PCR and CD317 protein levels by flow cytometry in several human glioblastoma cell lines. A cytotoxicity assay after treatment with HM1.24-ETA’ immunotoxin was performed in human glioblastoma cell lines. Results: Data on mRNA expression from the TCGA database demonstrated, that CD317 was upregulated in human glioblastomas compared to lower grade gliomas. In the group of glioblastoma patients increased CD317 mRNA expression was associated with decreased probability of survival ( p< 0.001). CD317 protein levels correlated directly with the tumor grade of astrocytic gliomas in the TMA. CD317 was expressed heterogeneously on mRNA and protein levels in the tested cell-lines in vitro. HM1.24-ETA’ induced cytotoxicity in CD317-positive glioblastoma cells in a concentration-dependent manner. Animal experiments currently performed suggest activity in glioblastoma xenografted mice. Conclusions: These data highlight CD317 as an interesting target antigen and HM1.24-ETA’ immunotoxin as a strategy for immunotherapy of glioblastoma patients.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ke Zhang ◽  
Zhuoying Li ◽  
Yunyang Lu ◽  
Linyi Xiang ◽  
Jiadong Sun ◽  
...  

Abstract Background The Wnt planar cell polarity (PCP) pathway is implicated in osteoarthritis (OA) both in animals and in humans. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the orientation and alignment of chondrocytes in the growth plate. However, its functional roles in OA still remain undefined. Here, we explored the effects of Vangl2 on OA chondrocyte in vitro and further elucidated the molecular mechanism of silencing Vangl2 in Wnt5a-overexpressing OA chondrocytes. Methods Chondrocytes were treated with IL-1β (10 ng/mL) to simulate the inflammatory microenvironment of OA. The expression levels of Vangl2, Wnt5a, MMPs, and related proinflammatory cytokines were measured by RT-qPCR. Small interfering RNA (siRNA) of Vangl2 and the plasmid targeting Wnt5a were constructed and transfected into ATDC5 cells. Then, the functional roles of silencing Vangl2 in the OA chondrocytes were investigated by Western blotting, RT-qPCR, and immunocytochemistry (ICC). Transfected OA chondrocytes were subjected to Western blotting to analyze the relationship between Vangl2 and related signaling pathways. Results IL-1β induced the production of Vangl2, Wnt5a, and MMPs in a time-dependent manner and the significantly increased expression of Vangl2. Vangl2 silencing effectively suppressed the expression of MMP3, MMP9, MMP13, and IL-6 at both gene and protein levels and upregulated the expression of type II collagen and aggrecan. Moreover, knockdown of Vangl2 inhibited the phosphorylation of MAPK signaling molecules (P38, ERK, and JNK) and P65 in Wnt5a-overexpressing OA chondrocytes. Conclusions For the first time, we demonstrate that Vangl2 is involved in the OA process. Vangl2 silencing can notably alleviate OA progression in vitro by inhibiting the expression of MMPs and increasing the formation of the cartilage matrix and can inhibit the proinflammatory effects of Wnt5a via MAPK and NF-κB pathway. This study provides new insight into the mechanism of cartilage inflammation.


1959 ◽  
Vol 234 (12) ◽  
pp. 3111-3114 ◽  
Author(s):  
Albert I. Winegrad ◽  
Walter N. Shaw ◽  
Francis D.W. Lukens ◽  
William C. Stadie

Diabetologia ◽  
2021 ◽  
Author(s):  
Juliana de Almeida-Faria ◽  
Daniella E. Duque-Guimarães ◽  
Thomas P. Ong ◽  
Lucas C. Pantaleão ◽  
Asha A. Carpenter ◽  
...  

Abstract Aims/hypothesis Levels of the microRNA (miRNA) miR-126-3p are programmed cell-autonomously in visceral adipose tissue of adult offspring born to obese female C57BL/6J mice. The spectrum of miR-126-3p targets and thus the consequences of its dysregulation for adipocyte metabolism are unknown. Therefore, the aim of the current study was to identify novel targets of miR-126-3p in vitro and then establish the outcomes of their dysregulation on adipocyte metabolism in vivo using a well-established maternal obesity mouse model. Methods miR-126-3p overexpression in 3T3-L1 pre-adipocytes followed by pulsed stable isotope labelling by amino acids in culture (pSILAC) was performed to identify novel targets of the miRNA. Well-established bioinformatics algorithms and luciferase assays were then employed to confirm those that were direct targets of miR-126-3p. Selected knockdown experiments were performed in vitro to define the consequences of target dysregulation. Quantitative real-time PCR, immunoblotting, histology, euglycaemic–hyperinsulinaemic clamps and glucose tolerance tests were performed to determine the phenotypic and functional outcomes of maternal programmed miR-126-3p levels in offspring adipose tissue. Results The proteomic approach confirmed the identity of known targets of miR-126-3p (including IRS-1) and identified Lunapark, an endoplasmic reticulum (ER) protein, as a novel one. We confirmed by luciferase assay that Lunapark was a direct target of miR-126-3p. Overexpression of miR-126-3p in vitro led to a reduction in Lunapark protein levels and increased Perk (also known as Eif2ak3) mRNA levels and small interference-RNA mediated knockdown of Lunapark led to increased Xbp1, spliced Xbp1, Chop (also known as Ddit3) and Perk mRNA levels and an ER stress transcriptional response in 3T3-L1 pre-adipocytes. Consistent with the results found in vitro, increased miR-126-3p expression in adipose tissue from adult mouse offspring born to obese dams was accompanied by decreased Lunapark and IRS-1 protein levels and increased markers of ER stress. At the whole-body level the animals displayed glucose intolerance. Conclusions/interpretation Concurrently targeting IRS-1 and Lunapark, a nutritionally programmed increase in miR-126-3p causes adipose tissue insulin resistance and an ER stress response, both of which may contribute to impaired glucose tolerance. These findings provide a novel mechanism by which obesity during pregnancy leads to increased risk of type 2 diabetes in the offspring and therefore identify miR-126-3p as a potential therapeutic target. Graphical abstract


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xinxin Yang ◽  
Haibo Yang ◽  
Fengdi Wu ◽  
Zhipeng Qi ◽  
Jiashuo Li ◽  
...  

Excessive manganese (Mn) can accumulate in the striatum of the brain following overexposure. Oxidative stress is a well-recognized mechanism in Mn-induced neurotoxicity. It has been proven that glutathione (GSH) depletion is a key factor in oxidative damage during Mn exposure. However, no study has focused on the dysfunction of GSH synthesis-induced oxidative stress in the brain during Mn exposure. The objective of the present study was to explore the mechanism of Mn disruption of GSH synthesis via EAAC1 and xCT in vitro and in vivo. Primary neurons and astrocytes were cultured and treated with different doses of Mn to observe the state of cells and levels of GSH and reactive oxygen species (ROS) and measure mRNA and protein expression of EAAC1 and xCT. Mice were randomly divided into seven groups, which received saline, 12.5, 25, and 50 mg/kg MnCl2, 500 mg/kg AAH (EAAC1 inhibitor) + 50 mg/kg MnCl2, 75 mg/kg SSZ (xCT inhibitor) + 50 mg/kg MnCl2, and 100 mg/kg NAC (GSH rescuer) + 50 mg/kg MnCl2 once daily for two weeks. Then, levels of EAAC1, xCT, ROS, GSH, malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and morphological and ultrastructural features in the striatum of mice were measured. Mn reduced protein levels, mRNA expression, and immunofluorescence intensity of EAAC1 and xCT. Mn also decreased the level of GSH, sulfhydryl, and increased ROS, MDA, 8-OHdG, and carbonyl in a dose-dependent manner. Injury-related pathological and ultrastructure changes in the striatum of mice were significantly present. In conclusion, excessive exposure to Mn disrupts GSH synthesis through inhibition of EAAC1 and xCT to trigger oxidative damage in the striatum.


FEBS Letters ◽  
1974 ◽  
Vol 49 (1) ◽  
pp. 65-69 ◽  
Author(s):  
P. Zumstein ◽  
J. Zapf ◽  
E.R. Froesch

2021 ◽  
Author(s):  
Ednilson Hilário Lopes-Junior ◽  
Gilbert de Oliveira Silveira ◽  
Camila Banca Guedes ◽  
Gratchela Dutra Rodrigues ◽  
Viviane Sousa Ribeiro ◽  
...  

Abstract Several studies described the effect of human TNF-α on Schistosoma mansoni. It affects the worm’s development, metabolism, egg-laying, changes in the parasite´s gene expression and protein phosphorylation. Data available concerning the influence of hTNF-α on egg-laying are controversial and understanding the mechanism of egg-laying regulation is essential in combating schistosomiasis. We characterized the effects of in vitro treatment of S. mansoni adult worms with different doses of hTNF-α (5, 20 and 40ng/mL) for five days. We explored the effects on the egg-laying rate, glucose, ATP metabolism, mRNA expression levels of lactate dehydrogenase, of glucose transporters and of SmTNFR, the parasite gene for hTNF-α receptor. hTNF-α influenced egg-laying in a time and dose dependent manner: with 40ng/mL, egg-laying increased on day 2 and decreased on days 3 and 4; 20 ng/mL dose, egg-laying decreased on day 3, while at 5ng/mL dose, egg-laying decreased on day 4. The total number of eggs produced was not affected, but the egg-laying dynamic was altered; the median egg-laying time decreased significantly due to treatment. At 5 and 20ng/mL hTNF-alpha, lactate production diminished on days 3 up to 5, while glucose uptake increased on day 5. At 40ng/mL, glucose uptake diminished on days 1 up to 3, while ATP accumulation was detected on day 5. No significant changes in the mRNA expression were detected in all treatments. Crosstalk involving the hTNF-alpha and the parasite signaling play a role in the fine regulation of the worm´s metabolism and physiology and points to new strategies for disease control.


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