Mesenchymal stromal cells affect cardiomyocyte growth through juxtacrine Notch-1/Jagged-1 signaling and paracrine mechanisms: clues for cardiac regeneration

The possibility to induce myocardial regeneration by the activation of resident cardiac stem cells (CSCs) has raised great interest. However, to propose endogenous CSCs as therapeutic options, a better understanding of the complex mechanisms controlling heart morphogenesis is needed, including the cellular and molecular interactions that cardiomyocyte precursors establish with cells of the stromal compartment. In the present study, we co-cultured immature cardiomyocytes from neonatal mouse hearts with mouse bone marrow-derived mesenchymal stromal cells (MSCs) to investigate whether these cells could influence cardiomyocyte growth in vitro. We found that cardiomyocyte proliferation was enhanced by direct co-culture with MSCs compared with the single cultures. We also showed that the proliferative response of the neonatal cardiomyocytes involved the activation of Notch-1 receptor by its ligand Jagged-1 expressed by the adjacent MSCs. In fact, the cardiomyocytes in contact with MSCs revealed a stronger immunoreactivity for the activated Notch-intracellular domain (Notch-ICD) as compared with those cultured alone and this response was significantly attenuated when MSCs were silenced for Jagged-1. The presence of various cardiotropic cytokines and growth factors in the conditioned medium of MSCs underscored the contribution of paracrine mechanisms to Notch-1 up-regulation by the cardiomyocytes. In conclusions these findings unveil a previously unrecognized function of MSCs in regulating cardiomyocyte proliferation through Notch-1/Jagged-1 pathway and suggest that stromal-myocardial cell juxtacrine and paracrine interactions may contribute to the development of new and more efficient cell-based myocardial repair strategies.     

Mother-offspring dialogue in early pregnancy: Impact of adverse environment on pregnancy maintenance and neurobiology

The mother-offspring dialogue begins even before implantation and is essential to signal pregnancy, establish robust contact, and maintain embryo growth and development. Any circumstance that disrupts the dialogue risks pregnancy problems. A new look at how stress impacts on pregnancy involves its adverse effects on the key pregnancy hormones of progesterone and prolactin. These effects have far-reaching consequences on pregnancy maintenance, maternal anxiety and embryo programming. This review focuses on early pregnancy and how stress might compromise the multi-layer, two-way communication between mother and embryo.     

Actions of neuropoietic cytokines and cyclic AMP in regenerative conditioning of rat primary sensory neurons

A conditioning lesion to peripheral axons of primary sensory neurons accelerates regeneration of their central axons in vivo or neurite outgrowth if the neurons are grown in vitro. Previous evidence has implicated neuropoietic cytokines and also cyclic AMP in regenerative conditioning. In experiments reported here, delivery through a lentivirus vector of ciliary neurotrophic factor to the appropriate dorsal root ganglion in rats was sufficient to mimic the conditioning effect of peripheral nerve injury on the regeneration of dorsal spinal nerve root axons. Regeneration in this experimental preparation was also stimulated by intraganglionic injection of dibutyryl cyclic AMP but the effects of ciliary neurotrophic factor and dibutyryl cyclic AMP were not additive. Dibutyryl cyclic AMP injection into the dorsal root ganglion induced mRNAs for two other neuropoietic cytokines, interleukin-6 and leukemia inhibitory factor and increased the accumulation of phosphorylated STAT3 in neuronal nuclei. The in vitro conditioning action of dibutyryl cyclic AMP was partially blocked by a pharmacological inhibitor of Janus kinase 2, a neuropoietic cytokine signaling molecule. We suggest that the beneficial actions of increased cyclic AMP activity on axonal regeneration of primary sensory neurons are mediated, at least in part, through the induction of neuropoietic cytokine synthesis within the dorsal root ganglion.     

Leukemia inhibitory factor signaling modulates both central nervous system demyelination and myelin repair

Leukemia inhibitory factor (LIF) receptor signaling limits the severity of inflammatory demyelination in experimental autoimmune encephalomyelitis, a T-cell dependent animal model of multiple sclerosis (MS) [Butzkueven et al. (2002) Nat Med 8:613-619]. To identify whether LIF exerts direct effects within the central nervous system to limit demyelination, we have studied the influence of LIF upon the phenotype of mice challenged with cuprizone, a copper chelator, which produces a toxic oligodendrocytopathy. We find that exogenously administered LIF limits cuprizone-induced demyelination. Knockout mice deficient in LIF exhibit both potentiated demyelination and oligodendrocyte loss after cuprizone challenge, an effect that is ameliorated by exogenous LIF, arguing for a direct beneficial effect of endogenous LIF receptor signaling. Numbers of oligodendrocyte progenitor cells in cuprizone-challenged mice are not influenced by either exogenous LIF or LIF deficiency, arguing for effects directed to the differentiated oligodendrocyte. Studies on the influence of LIF upon remyelination after cuprizone challenge fail to reveal any significant effect of exogenous LIF. The LIF-knockout mice do, however, display impaired remyelination, although oligodendrocyte replenishment, previously identified to occur from the progenitor pool, is not significantly compromised. Thus endogenous LIF receptor signaling is not only protective of oligodendrocytes but can also enhance remyelination, and exogenous LIF has therapeutic potential in limiting the consequences of oligodendrocyte damage.     

超排卵着床期小鼠子宫内膜LIF表达与雌孕激素的关系

目的 研究超排卵对围着床期小鼠子宫内膜UF表达的影响及其与雌孕激素的关系,探讨超排卵是否影响子宫内膜容受性的形成.方法 将实验动物随机分为超排卵妊娠组和正常妊娠对照组,分别选取动情周期当天、合笼后发现阴道栓第2天、第4天、第6天、第8夫共五个时间点取小鼠子宫内膜,用免疫组化和原位杂交法测定小鼠子宫内膜LIF的蛋白表达和LIF mRNA的表达.同时分别测定小鼠血清雌、孕激素水平.结果 正常妊娠组小鼠LIF蛋白在围着床期子宫内膜上的表达动情周期较低,在妊娠之后开始上升,在妊娠第4天(即小鼠孕卵着床当天)达到最高峰(P<0.05),继之在子宫内膜的表达下降.在妊娠第8天降到非孕期水平:超排卵组小鼠围着床期子宫内膜LIF蛋白随着妊娠天数而表达增加,在妊娠第2天达到最高峰(P<0.05),继之在子宫内膜的表达下降,在妊娠第8天降至非孕期水平.超排卵组与对照组相比较,其在妊娠第2天的表达明显高于对照组(P<0.05),在妊娠第4天的表达明显低于对照组(P<0.05);超排卵组和对照组小鼠血清雌、孕激素浓度均随妊娠天数的增加逐渐升高.在各时间点超排卵组的雌、孕激素水平明显高于对照组(P<0.05).小鼠子宫内膜LIF蛋白的表达与雌激素水平在一定范嗣内成正相关,超过一定临界水平后呈负相关(P<0.05),而与孕激素未发现有相关性(P>0.05).结论 超排卵可能对小鼠围着床期子宫内膜LIF蛋白的表达有影响,使其表达峰值提前,由此推测影响子宫内膜容受性的建立;体内雌激素水平与同着床期子宫内膜LIF蛋白的表达有相关性,但尚不能排除孕激素水平与其有相关性,说明LIF蛋白的表达与雌激素的调控有关,并且可能存在一定的数量关系.     

白血病抑制因子在自然流产绒毛组织中的表达

目的探讨白血病抑制因子(LIF)在绒毛组织中的表达及其与先兆流产及难免流产的关系.方法选择2003年10月～2004年8月来我院就诊、自愿采用人工流产术终止妊娠者为检测对象,按诊断分为正常早孕组、先兆流产组和难免流产组,每组各30例,采肘静脉血并收集流产绒毛组织.采用放射免疫法检测3组血清孕酮及人绒毛膜促性腺激素(hCG)水平,采用Western blot印迹杂交技术对3组流产绒毛组织中LIF的表达进行测定.结果难免流产组血清孕酮及hCG水平为(36.2±18.4)nmol/L及(13.6±3.1)kU/L显著低于正常早孕组(93.6±27.3)nmol/L及(70.2±15.9)kU/L和先兆流产组(89.5±25.2)nmol/L及(60.3±13.7)kU/L,差别均有显著性意义(均P＜0.01),先兆流产组与正常早孕组间差别无显著性意义(均P＞0.05);正常早孕组、先兆流产组和难免流产组绒毛组织中LIF平均相对表达量依次降低,分别为1.12±0.11、1.04±0.08、0.23±0.02,难免流产组LIF表达量显著低于其它两组(P＜0.01),先兆流产组与正常早孕组间LIF的表达差别无显著性意义(P＞0.05).结论 LIF在早孕者流产绒毛组织中的表达量降低,可能与hCG及孕酮分泌下降有关,是最终导致难免流产的原因之一.     

Lymphoblastogenesis inhibitory factor produced by human lung cancer cell lines.

A comparative study of the inhibitory effect of cell-free supernatants (CFS) from human lung cancer cell lines (ChaGo and PC-1) and from a human embryo fibroblast cell line on lymphocyte blastogenesis indicated that both lung cancer cell lines produce a large amount of the inhibitory factor while the production of such a factor from a control noncancer cell line is essentially very minimal or absent. The inhibitory effect of CFS of the lung cancer cell lines is not due to direct cytotoxicity. The inhibitory effect is found to be partially sensitive to heat treatment. A significant inhibition is still seen, even when the CFS of the lung cancer cell lines were present for 1 hour prior to the addition of phytohemagglutinin (PHA).     

In vivoEffect of Recombinant Human Leukemia Inhibitory Factor in Primates

Leukemia inhibitory factor(LIF) is known to be a causative factor for cacbexia and thrombocytosis in nude mice bearing human cancer cells. In the present study, we investigated whether recombinant human (rh) LIF can induce these biological activities in a primate model. rhLIF was synthesized by the expression of LIF protein in Escherichia coli . rhLIF (5, 20, or 80μ/kg) was administered subcutaneously twice daily to cynomolgus monkeys for 14 consecutive days. A remarkable decrease of body weight (10%) was observed in the 80μg/kg/day group. Approximately two-fold increases in platelet counts were observed at doses higher than 5 /μg/kg/day when compared with control counts. These biological effects disappeared soon after the cessation of rhLIF treatment. Macroscopically, a remarkable reduction in subcutaneous fatty tissues and severe splenomegaly were observed. The results of this study demonstrate that rhLIF induces weight loss and thrombocytosis in a primate model.     

The paracrinology of tubal ectopic pregnancy

Mineralocorticoid receptor (MR) signaling is pivotal for numerous physiological processes and implicated in various pathological conditions concerning among others, tight epithelia, central nervous and cardiovascular systems. For decades, the pleiotropic actions of MR have been investigated using animal and cellular models as well as by clinical studies. Here is reviewed and contextualized the utilization of a strategy that recently emerged to analyze the complexity of MR signaling: the derivation and differentiation of mouse embryonic stem (ES) cell models. ES cells were derived from wild-type or transgenic MR overexpressing animals. Undifferentiated ES cells were differentiated into cardiomyocytes, neurons and adipocytes, these cell types being important pathophysiological targets of MR. These approaches have already brought new insights concerning MR effect on cardiomyocyte contractility and ionic channel remodeling, in the regulation of neuronal MR expression and its positive role on neuron survival. Differentiated ES cell models thus constitute powerful and promising tools to further decipher the molecular mechanisms of cell-specific MR actions.