MyMedR

Displaying publications 81 - 84 of 84 in total

Abstract:

Sort:

Fulltext Decoding the differentiation of mesenchymal stem cells into mesangial cells at the transcriptomic level

Wong CY, Chang YM, Tsai YS, Ng WV, Cheong SK, Chang TY, et al.

BMC Genomics, 2020 Jul 07;21(1):467.
PMID: 32635896 DOI: 10.1186/s12864-020-06868-5

BACKGROUND: Mesangial cells play an important role in the glomerulus to provide mechanical support and maintaine efficient ultrafiltration of renal plasma. Loss of mesangial cells due to pathologic conditions may lead to impaired renal function. Mesenchymal stem cells (MSC) can differentiate into many cell types, including mesangial cells. However transcriptomic profiling during MSC differentiation into mesangial cells had not been studied yet. The aim of this study is to examine the pattern of transcriptomic changes during MSC differentiation into mesangial cells, to understand the involvement of transcription factor (TF) along the differentiation process, and finally to elucidate the relationship among TF-TF and TF-key gene or biomarkers during the differentiation of MSC into mesangial cells.
RESULTS: Several ascending and descending monotonic key genes were identified by Monotonic Feature Selector. The identified descending monotonic key genes are related to stemness or regulation of cell cycle while ascending monotonic key genes are associated with the functions of mesangial cells. The TFs were arranged in a co-expression network in order of time by Time-Ordered Gene Co-expression Network (TO-GCN) analysis. TO-GCN analysis can classify the differentiation process into three stages: differentiation preparation, differentiation initiation and maturation. Furthermore, it can also explore TF-TF-key genes regulatory relationships in the muscle contraction process.
CONCLUSIONS: A systematic analysis for transcriptomic profiling of MSC differentiation into mesangial cells has been established. Key genes or biomarkers, TFs and pathways involved in differentiation of MSC-mesangial cells have been identified and the related biological implications have been discussed. Finally, we further elucidated for the first time the three main stages of mesangial cell differentiation, and the regulatory relationships between TF-TF-key genes involved in the muscle contraction process. Through this study, we have increased fundamental understanding of the gene transcripts during the differentiation of MSC into mesangial cells.

Matched MeSH terms: Muscle Contraction
Fulltext Effect of quantity and quality of pre-exercise carbohydrate meals on central fatigue

Khong TK, Selvanayagam VS, Hamzah SH, Yusof A

J Appl Physiol (1985), 2018 10 01;125(4):1021-1029.
PMID: 29975601 DOI: 10.1152/japplphysiol.00221.2018

Both the quantity and quality of pre-exercise carbohydrate (CHO) meals have been shown to improve endurance performance. However, their role in attenuating central fatigue (CF) is inconclusive. The use of neurophysiological techniques, such as voluntary activation (VA) and the central activation ratio (CAR), alongside maximum voluntary contraction (MVC) and sustained MVC (sMVC) can provide information on CF. Hence, the objective of this study was to investigate the effects of isocaloric pre-exercise meals: 1) a high versus low quantity of CHO and 2) a high quantity of CHO with a high versus low glycemic index (GI) on MVC, VA, and CAR following a 90-min run. The high and low quantity of CHO was 1.5 and 0.8 g/kg body wt, respectively, and high and low GI was ~75 and ~40, respectively. Blood insulin, serotonin, tryptophan, and gaseous exchange were also measured. High CHO preserved sMVC, VA, CAR, and serotonin postrunning with greater CHO oxidation and insulin response, whereas in low CHO, greater reductions in sMVC, VA, and CAR were accompanied by higher serotonin and fat oxidation with lower insulin response. These observations indicate central involvements. Meanwhile, high GI CHO better preserved force (sMVC), CAR, and tryptophan with greater CHO oxidation and insulin response compared with low GI. The findings of this study suggest that pre-exercise meals with varying quantity and quality of CHO can have an effect on CF, where greater CHO oxidation and insulin response found in both high CHO and high GI lead to attenuation of CF. NEW & NOTEWORTHY This paper examined the effects of carbohydrate interventions (high and low: quantity and quality wise) on central activity during prolonged exercise using mainly neurophysiological techniques along with gaseous exchange and blood insulin, serotonin, and tryptophan data.

Matched MeSH terms: Muscle Contraction
Comparison of relaxin receptors in rat isolated atria and uterus by use of synthetic and native relaxin analogues

Tan YY, Wade JD, Tregear GW, Summers RJ

Br J Pharmacol, 1998 Feb;123(4):762-70.
PMID: 9517397

1. The receptors for relaxin in the rat atria and uterus were investigated and compared by use of a series of synthetic and native relaxin analogues. The assays used were the positive chronotropic and inotropic effects in rat spontaneously beating, isolated right atrium and electrically driven left atrium and the relaxation of K+ precontracted uterine smooth muscle. 2. Relaxin analogues with an intact A- and B-chain were active in producing powerful chronotropic and inotropic effects in the rat isolated atria at nanomolar concentrations. Single-chain analogues and structural homologues of relaxin such as human insulin and sheep insulin-like growth factor I had no agonist action and did not antagonize the effect of the B29 form of human gene 2 relaxin. 3. Shortening the B-chain carboxyl terminal of human gene 1 (B2-29) relaxin to B2-26 reduced the activity of the peptide and removal of another 2 amino acid residues (B2-24) abolished the activity. This suggests that the B-chain length may be important for determination of the activity of relaxin. More detailed studies are needed to determine the effect of progressive amino acid removal on the structure and the bioactivity of relaxin. 4. Porcine prorelaxin was as active as porcine relaxin on a molar basis, suggesting that the presence of the intact C-peptide did not affect the binding of the prorelaxin to the receptor to produce functional responses. 5. Relaxin caused relaxation of uterine longitudinal and circular smooth muscle precontracted with 40 mM K+. The pEC50 values for human gene 2 and porcine relaxins were lower than those in the atrial assay, but rat relaxin had similar pEC50 values in both atrial and uterine assays. Rat relaxin was significantly less potent than either human gene 2 or porcine relaxin in the atrial assay, but in the uterine assay they were equipotent. The results suggest that the relaxin receptor or the signalling pathway in rat atria may differ from that in the uterus.

Matched MeSH terms: Muscle Contraction
Fulltext In-vitro and in-vivo validation of ethnopharmacological uses of methanol extract of Isodon rugosus Wall. ex Benth. (Lamiaceae)

Janbaz KH, Arif J, Saqib F, Imran I, Ashraf M, Zia-Ul-Haq M, et al.

BMC Complement Altern Med, 2014 Feb 22;14:71.
PMID: 24559094 DOI: 10.1186/1472-6882-14-71

BACKGROUND: Isodon rugosus is used in folk Pakistan traditional practices to cure ailments related to gastrointestinal, respiratory and cardiovascular problems. Present study was undertaken to validate these folkloric uses.
METHODS: A crude methanol extract of the aerial parts of Isodon rugosus (Ir.Cr.) was used for both in vitro and in vivo experiments. The plant extract was tested on isolated rabbit jejunum preparations for possible presence of spasmolytic activity. Moreover, isolated rabbit tracheal and aorta preparations were used to ascertain the relaxant effects of the extract. Acetylcholinesterase and butyrylcholinesterase inhibitory activities of Ir.Cr were also determined as well as its antioxidant activity. The in vivo antiemetic activity of the extract was evaluated by using the chick emesis model, while the analgesic and antipyretic activities were conducted on albino mice.
RESULTS: The application of the crude extract of I. rugosus to isolated rabbit jejunum preparations exhibited relaxant effect (0.01-0.3 mg/ml). The Ir.Cr also relaxed K+(80 m M)-induced spastic contractions in isolated rabbit jejunum preparations and shifted the Ca+2 concentration response curves towards right (0.01-0.3 mg/ml). Similarly, the extract, when applied to the isolated rabbit tracheal preparations relaxed the carbachol (1 μM)--as well as K+ (80 mM)-induced contractions in a concentration range of 0.01-1.0 mg/ml. Moreover, it also relaxed (0.01-3.0 mg/ml) the phenylephrine (1 μM)- and K+ (80 mM)-induced contractions in isolated rabbit aorta preparations. The Ir.Cr (80 mg/kg) demonstrated antipyretic activity on pyrogen-induced pyrexia in rabbits as compared to aspirin as standard drug. The Ir.Cr also exhibited anti-oxidant as well as inhibitory effect on acetyl- and butyryl-cholinesterase and lipoxygenase (0.5 mg/ml).
CONCLUSIONS: The observed relaxant effect on isolated rabbit jejunum, trachea and aorta preparations caused by Ir.Cr is possibly to be mediated through Ca+2 channel blockade and therefore may provided scientific basis to validate the folkloric uses of the plant in the management of gastrointestinal, respiratory and cardiovascular ailments. The observed antioxidant activity as well as the lipoxygenase inhibitory activity may validate its traditional use in pain and inflammations.

Matched MeSH terms: Muscle Contraction/drug effects