Pleiotropic effects of sonic hedgehog on muscle satellite cells

Muscle satellite cells are believed to form a stable, self-renewing pool of stem cells in adult muscle where they function in tissue growth and repair. A regulatory disruption of growth and differentiation of these cells is assumed to result in tumor formation. Here we provide for the first time evidence that sonic hedgehog (Shh) regulates the cell fate of adult muscle satellite cells in mammals. Shh promotes cell division of satellite cells (and of the related model C2C12 cells) and prevents their differentiation into multinucleated myotubes. In addition, Shh inhibits caspase-3 activation and apoptosis induced by serum deprivation. These effects of Shh are reversed by simultaneous administration of cyclopamine, a specific inhibitor of the Shh pathway. Taken together, Shh acts as a proliferation and survival factor of satellite cells in the adult muscle. Our results support the hypothesis of the rhabdomyosarcoma origin from satellite cells and suggest a role for Shh in this process.Received 23 February 2005; received after revision 2 May 2005; accepted 9 June 2005     

Increased apoptosis in differentiating p27-deficient mouse embryonic stem cells

In mouse embryonic stem (mES) cells, the expression of p27 is elevated when differentiation is induced. Using mES cells lacking p27 we tested the importance of p27 for the regulation of three critical cellular processes: proliferation, differentiation, and apoptosis. Although cell cycle distribution, DNA synthesis, and the activity of key G1/S-regulating cyclin-dependent kinases remained unaltered in p27-deficient ES cells during retinoic acid-induced differentiation, the amounts of cyclin D2 and D3 in such cells were much lower compared with normal mES cells. The onset of differentiation induces apoptosis in p27-deficient cells, the extent of which can be reduced by artificially increasing the level of cyclin D3. We suggest that the role of p27 in at least some differentiation pathways of mES cells is to prevent apoptosis, and that it is not involved in slowing cell cycle progression. We also propose that the pro-survival function of p27 is realized via regulation of metabolism of D-type cyclin(s).Received 25 February 2004; received after revision 5 April 2004; accepted 15 April 2004     

Polycystic kidney diseases: From molecular discoveries to targeted therapeutic strategies

Polycystic kidney diseases (PKDs) represent a large group of progressive renal disorders characterized by the development of renal cysts leading to end-stage renal disease. Enormous strides have been made in understanding the pathogenesis of PKDs and the development of new therapies. Studies of autosomal dominant and recessive polycystic kidney diseases converge on molecular mechanisms of cystogenesis, including ciliary abnormalities and intracellular calcium dysregulation, ultimately leading to increased proliferation, apoptosis and dedifferentiation. Here we review the pathobiology of PKD, highlighting recent progress in elucidating common molecular pathways of cystogenesis. We discuss available models and challenges for therapeutic discovery as well as summarize the results from preclinical experimental treatments targeting key disease-specific pathways. Received 8 August 2007; received after revision 19 September 2007; accepted 2 October 2007     

Protein farnesylation in mammalian cells: effects of farnesyltransferase inhibitors on cancer cells

Protein farnesylation, catalyzed by protein farnesyltransferase, plays important roles in the membrane association and protein-protein interaction of a number of eukaryotic proteins. Recent development of farnesyltransferase inhibitors (FTIs) has led to further insight into the biological significance of farnesylation in cancer cells. A number of reports point to the dramatic effects FTIs exert on cancer cells. In addition to inhibiting anchorage-independent growth, FTIs cause changes in the cell cycle either at the G1/S or at the G2/M phase. Furthermore, induction of apoptosis by FTIs has been reported. FTIs also affects the actin cytoskeleton and cell morphology. This review summarizes these reports and discusses implications for farnesylated proteins responsible for these FTI effects. Received 17 April 2001; received after revision 28 May 2001; accepted 28 May 2001     

Morphogenic effects of halogenated thymidine analogs onDrosophila III. 5-Iododeoxyuridine

Zusammenfassung Die Häufigkeit der durch 5-Iododeoxyuridin (IUdR) beiDrosophila induzierten Abnormalitäten kann durch gleichzeitige Fütterung der Larven mit 5-Fluorouracil (FU) erhöht werden. Die Menge des in dieDrosophila-DNS inkorporierten IUdR ist bei Anwesenheit von FU höher; die Verteilung dieser IUdR-DNS im CsCl-Dichtegradienten ist verschieden von der in Abwesenheit von FU synthetisierten DNS.

---

---

This research was supported by a grant No. DRG-1113 from the Damon Runyon Memorial Fund.     

Divergent effects of the major mast cell products histamine, tryptase and TNF-alpha on human fibroblast behaviour

Fibroblast proliferation is a key process in tissue remodeling and mast cells (MCs) are thought to play a crucial role. Having established that the three major MC products, tryptase, histamine and TNF-alpha (TNF) are normally present in human skin MCs, which are in close proximity to dermal fibroblasts, we studied their individual effects on cell cycle-controlled human dermal fibroblasts (HFFF2). These cells express receptors (H1, PAR2, TNFR1/2) for the major MC mediators, but only tryptase or a PAR2 agonist peptide stimulated proliferation and gene expression. TNF was antimitotic, and histamine, while elevating intracellular Ca²⁺ levels at high concentrations, did not affect proliferation. We conclude that MC products but also composition and numbers of respective receptors on fibroblasts are crucially responsible for fibroproliferative events. Received: 28 June 2005; received after revision 28 September 2005; accepted 6 October 2005     

A dioestrous increase in thymocyte proliferation during the oestrous cycle

Summary Coitus, which precedes internal fertilisation, is a unique physiological event which allows motile allogeneic spermatozoa to enter the female host and invade her tissues. The cyclic cellular proliferation observed in the thymus of the female rat may be an important preparation of her immune system for this event.     

氧化苦参碱对人宫颈癌SiHa细胞株增殖及凋亡的影响

目的研究氧化苦参碱对体外人宫颈癌SiHa细胞株增殖活性及凋亡的影响。方法对人宫颈癌SiHa细胞株进行体外培养,经氧化苦参碱处理的细胞组为实验组,未经处理组为对照组。采用MTT细胞存活实验检测氧化苦参碱对入宫颈鳞癌SiHa细胞的增殖影响,并计算IC50;倒置相差显微镜下观察不同浓度的氧化苦参碱作用48h后SiHa细胞的形态改变;Hoechst33258染色法和Western blot法检测氧化苦参碱对SiHa细胞核及凋亡相关蛋白(P53、Bax及Bcl-2)表达水平的影响。结果 MTT结果显示氧化苦参碱剂量-时间依耐性抑制人宫颈癌SiHa细胞的体外增殖(P0.05),计算24 h、48 h和72 h的IC50分别为(1 028.41±3.57)μg/ml、(701.72±6.01)μg/ml和(406.88±2.15)μg/ml;氧化苦参碱处理48 h后,SiHa细胞的形态特征及数目发生显著变化,且随氧化苦参碱浓度的增加而愈加明显;Hoechst33258染色证实氧化苦参碱处理后SiHa细胞发生凋亡,可见典型的凋亡特征;Western blot结果证实氧化苦参碱(700μg/ml、1 600μg/ml)处理48 h后,和对照组比较,药物处理组细胞凋亡周期蛋白P53、Bax表达上调(P0.05),而Bcl-2表达下调(P0.05),Bax/Bcl-2的比率明显增加(P0.05)。结论氧化苦参碱可抑制体外人宫颈癌SiHa细胞的体外增殖活性发挥其抗肿瘤作用,其作用机制可能诱导SiHa细胞的凋亡有关。     

Selective potentiating effects of metal ions on vasopressom

Zusammenfassung Der Effekt von Na⁺-, NH₄ ⁺- und Ca⁺⁺-Ionen auf die Blutdruckaktivität von Arginin-Vasopressom wurde untersucht und mit analogen Experimenten (Val⁵-Angiotensin II-Asp¹--Amid) verglichen. Die Wirkungsweise der Ionen-induzierten Potenzierung von Vasopressin wird diskutiert.

---

---

Supported by USPHS Grant No. AM-13567.

---

Abbreviations used are: AVP, arginine-vasopressin; bp, blood pres sure; U, unit;n, number of experiments; , mean value; S.E. standard error;p, level of significance; NS, not significant.     

解聚复肾宁对大鼠肾小球系膜细胞增殖和细胞周期的影响

目的 观察中药复方解聚复肾宁（JJFSN）对高耱环境下大鼠肾小球系膜细胞（mesangial cell,MC）增殖和细胞周期的影响.方法 以高糖诱导MC增殖,采用血清药理学方法制备不同浓度JJFSN舍药血清,加入培养液中,用MTT法检测细胞增殖,流式细胞技术检测细胞周期.结果 MTT显示：JJFSN含药血清可抑制高糖诱导的MC过度增殖（P＜0.05）,并且这种作用具有药物剂量和时间依赖关系.流式细胞技术分析表明：JJFSN可逆转高糖对细胞周期的影响,使G0/G1期细胞比例增加,S期细胞比例下降（P＜0.05） 在高浓度时还能促进MC细胞凋亡.结论 JJFSN可以通过调节细胞周期,促进细胞凋亡,从而抑制高糖诱导的MC过度增殖,这可能是JJFSN防治DN早期的作用杌理.     

Angiogenesis and signal transduction in endothelial cells

Endothelial cells receive multiple information from their environment that eventually leads them to progress along all the stages of the process of formation of new vessels. Angiogenic signals promote endothelial cell proliferation, increased resistance to apoptosis, changes in proteolytic balance, cytoskeletal reorganization, migration and, finally, differentiation and formation of a new vascular lumen. We aim to review herein the main signaling cascades that become activated in angiogenic endothelial cells as well as the opportunities of modulating angiogenesis through pharmacological interference with these signaling mechanisms. We will deal mainly with the mitogen-activated protein kinases pathway, which is very important in the transduction of proliferation signals; the phosphatidylinositol-3-kinase/protein kinase B signaling system, particularly essential for the survival of the angiogenic endothelium; the small GTPases involved in cytoskeletal reorganization and migration; and the kinases associated to focal adhesions which contribute to integrate the pathways from the two main sources of angiogenic signals, i.e. growth factors and the extracellular matrix.Received 13 February 2004; received after revision 25 March 2004; accepted 19 April 2004     

Ras proteins in the control of the cell cycle and cell differentiation

The Ras family of small GTPases includes three closely related proteins: H-, K-, and N-Ras. Ras proteins are involved in the transduction of signals elicited by activated surface receptors, acting as key components by relaying signals downstream through diverse pathways. Mutant, constitutively activated forms of Ras proteins are frequently found in cancer. While constitutive Ras activation induces oncogenic-like transformation in immortalized fibroblasts, it causes growth arrest in primary vertebrate cells. Induction of p53 and cyclin-dependent kinase inhibitors such as p15^INK4b, p16^INK4a, p19^ARF, and p21^WAF1 accounts for this response. Interestingly, while ras has usually been regarded as a transforming oncogene, the analysis of Ras function in most of the cellular systems studied so far indicates that the promotion of differentiation is the most prominent effect of Ras. While in some cell types, particularly muscle, Ras inhibits differentiation, in others such as neuronal, adipocytic, or myeloid cells, Ras induces differentiation, in some cases accompanied by growth arrest. Several possible mechanisms for the pleiotropic effects of Ras in animal cells are discussed. Received 8 March 2000; received after revision 24 May 2000; accepted 24 May 2000     

Selective effects of gonadal steroids on the response of peripheral serotonin receptors

Summary The maximal contraction provoked by serotonin (5-HT) in isolated stomach strips of adult rats, a functional index for peripheral 5-HT receptors, was sexually differentiated, androgen-sensitive, and estrogen refractory. This is at variance with the reported sensitivity of central 5-HT receptors to estrogen.     

Selective effects of gonadal steroids on the response of peripheral serotonin receptors

The maximal contraction provoked by serotonin (5-HT) in isolated stomach strips of adult rats, a functional index for peripheral 5-HT receptors, was sexually differentiated, androgen-sensitive, and estrogen refractory. This is at variance with the reported sensitivity of central 5-HT receptors to estrogen.     

Regulation of the cell cycle following DNA damage in normal and Ataxia telangiectasia cells

A proportion of the population is exposed to acute doses of ionizing radiation through medical treatment or occupational accidents, with little knowledge of the immedate effects. At the cellular level, ionizing radiation leads to the activation of a genetic program which enables the cell to increase its chances of survival and to minimize detrimental manifestations of radiation damage. Cytotoxic stress due to ionizing radiation causes genetic instability, alterations in the cell cycle, apoptosis, or necrosis. Alterations in the G1, S and G2 phases of the cell cycle coincide with improved survival and genome stability. The main cellular factors which are activated by DNA damage and interfere with the cell cycle controls are: p53, delaying the transition through the G1-S boundary; p21^WAF1/CIPI, preventing the entrance into S-phase; proliferating cell nuclear antigen (PCNA) and replication protein A (RPA), blocking DNA replication; and the p53 variant protein p53as together with the retinoblastoma protein (Rb), with less defined functions during the G2 phase of the cell cycle. By comparing a variety of radioresistant cell lines derived from radiosensitive ataxia talangiectasia cells with the parental cells, some essential mechanisms that allow cells to gain radioresistance have been identified. The results so far emphasise the importance of an adequate delay in the transition from G2 to M and the inhibition of DNA replication in the regulation of the cell cycle after exposure to ionizing radiation.     

Effect of dipyridamole and adenosine monophosphate on cell proliferation in the hemopoietic tissue of normal and gamma-irradiated mice

Combined treatment with dipyridamole and adenosine monophosphate enhances cell proliferation in the hemopoietic tissue of normal and gamma-irradiated mice. This effect can be explained by the elevation of extracellular adenosine, and the receptor-mediated activation of the cell adenylate cyclase system.     

Autoradiogaphic investigation of cell proliferation in the adrenal cortex of castrated female rats under the influence of oestradiol

Summary Ovariectomy and subsequent treatment with ovarian hormone produces a temporary increase in DNA-synthesizing cells in the zona glomerulosa of the adrenal cortex.