Cyclin E-p27 opposition and regulation of the G1 phase of the cell cycle in the murine neocortical PVE: a quantitative analysis of mRNA in situ hybridization

We have analyzed the expression patterns of mRNAs of five cell cycle related proteins in the ventricular zone of the neocortical cerebral wall over the course of the neuronogenetic interval in the mouse. One set of mRNAs (cyclin E and p21) are initially expressed at high levels but expression then falls to a low asymptote. A second set (p27, cyclin B and cdk2) are initially expressed at low levels but ascend to peak levels only to decline again. These patterns divide the overall neuronogenetic interval into three phases. In phase 1 cyclin E and p21 levels of mRNA expression are high, while those of mRNAs of p27, cdk2 and cyclin B are low. In this phase the fraction of cells leaving the cycle after each mitosis, Q, is low and the duration of the G1 phase, TG1, is short. In phase 2 levels of expression of cyclin E and p21 fall to asymptote while levels of expression of mRNA of the other three proteins reach their peaks. Q increases to approach 0.5 and TG1 increases even more rapidly to approach its maximum length. In phase 3 levels of expression of cyclin E and p21 mRNAs remain low and those of the mRNAs of the other three proteins fall. TG1 becomes maximum and Q rapidly increases to 1.0. The character of these phases can be understood in part as consequences of the reciprocal regulatory influence of p27 and cyclin E and of the rate limiting functions of p27 at the restriction point and of cyclin E at the G1 to S transition.     

Cell output,cell cycle duration and neuronal specification: a model of integrated mechanisms of the neocortical proliferative process

The neurons of the neocortex are generated over a 6 day neuronogenetic interval that comprises 11 cell cycles. During these 11 cell cycles, the length of cell cycle increases and the proportion of cells that exits (Q) versus re-enters (P) the cell cycle changes systematically. At the same time, the fate of the neurons produced at each of the 11 cell cycles appears to be specified at least in terms of their laminar destination. As a first step towards determining the causal interrelationships of the proliferative process with the process of laminar specification, we present a two-pronged approach. This consists of (i) a mathematical model that integrates the output of the proliferative process with the laminar fate of the output and predicts the effects of induced changes in Q and P during the neuronogenetic interval on the developing and mature cortex and (ii) an experimental system that allows the manipulation of Q and P in vivo. Here we show that the predictions of the model and the results of the experiments agree. The results indicate that events affecting the output of the proliferative population affect both the number of neurons produced and their specification with regard to their laminar fate.     

Differential regulation of connexin 26 and 43 in murine neocortical precursors

Proliferating cells of the developing murine neocortex couple together into clusters during neurogenesis. Previously, we have shown that these clusters contain neural precursors in all phases of the cell cycle except M phase, and that they extend a nestin-expressing process from the cluster to the pial surface. In addition, coupling within neocortical cell clusters is a dynamic process related to the cell cycle, with maximal coupling in S/G2 phase, uncoupling in M phase and then recoupling during G1 and S phases of the cell cycle. In the present study, we use immunohistochemistry to demonstrate that cycling neocortical cells as well as radial glial cells express the gap junction proteins connexin 26 and connexin 43. Furthermore, we demonstrate that biocytin labeled clusters extend processes to the pial surface that express the glial cell antigen RC2. Lastly, by combining bromodeoxyuridine and connexin immunohistochemistry on acutely dissociated neocortical cells, we show that the percentage of cycling cells immunoreactive to connexin 26 and connexin 43 changes through the cell cycle. These results indicate that radial glial cells as well as neural precursors couple into clusters, and suggest that through differential regulation of connexins, neocortical precursors may compartmentalize as they progress through the cell cycle.     

Notch signaling inhibition induces G0/G1 arrest in murine Leydig cells

As a highly evolutionarily conserved signaling pathway, Notch widely participates in cell‐fate decisions and the development of various tissues and organs. In male reproduction, research on the Notch signaling pathway has mainly concentrated on germ cells and Sertoli cells. Leydig cells are the primary producers of testosterone and play important roles in spermatogenesis and maintaining secondary sexual characteristics. In this study, we used TM3 cells, a murine adult Leydig cell line, to investigate the expression profiles of Notch receptors and ligands and observe the effect of Notch signaling on the proliferation of TM3 cells. We found that Notch 1–3 and the ligands Dll‐1 and Dll‐4 were expressed in TM3 cells, Notch 1–3 and the ligand Dll‐1 were expressed in testis interstitial Leydig cells, and Notch signaling inhibition suppressed the proliferation of TM3 cells and induced G0/G1 arrest. Inhibition of Notch signaling increased the expression of p21^Waf1/Cip1 and p27. Overall, our results suggest that Notch inhibition suppresses the proliferation of TM3 cells and P21^Waf1/Cip1, and p27 may contribute to this process.     

A murine model of neurofibromatosis type 1 tibial pseudarthrosis featuring proliferative fibrous tissue and osteoclast‐like cells

Neurofibromatosis type 1 (NF1) is a common genetic condition caused by mutations in the NF1 gene. Patients often suffer from tissue‐specific lesions associated with local double‐inactivation of NF1. In this study, we generated a novel fracture model to investigate the mechanism underlying congenital pseudarthrosis of the tibia (CPT) associated with NF1. We used a Cre‐expressing adenovirus (AdCre) to inactivate Nf1 in vitro in cultured osteoprogenitors and osteoblasts, and in vivo in the fracture callus of Nf1^flox/flox and Nf1^flox/? mice. The effects of the presence of Nf1^null cells were extensively examined. Cultured Nf1^null‐committed osteoprogenitors from neonatal calvaria failed to differentiate and express mature osteoblastic markers, even with recombinant bone morphogenetic protein‐2 (rhBMP‐2) treatment. Similarly, Nf1^null‐inducible osteoprogenitors obtained from Nf1 mouse muscle were also unresponsive to rhBMP‐2. In both closed and open fracture models in Nf1^flox/flox and Nf1^flox/? mice, local AdCre injection significantly impaired bone healing, with fracture union being <50% that of wild type controls. No significant difference was seen between Nf1^flox/flox and Nf1^flox/? mice. Histological analyses showed invasion of the Nf1^null fractures by fibrous and highly proliferative tissue. Mean amounts of fibrous tissue were increased upward of 10‐fold in Nf1^null fractures and bromodeoxyuridine (BrdU) staining in closed fractures showed increased numbers of proliferating cells. In Nf1^null fractures, tartrate‐resistant acid phosphatase–positive (TRAP+) cells were frequently observed within the fibrous tissue, not lining a bone surface. In summary, we report that local Nf1 deletion in a fracture callus is sufficient to impair bony union and recapitulate histological features of clinical CPT. Cell culture findings support the concept that Nf1 double inactivation impairs early osteoblastic differentiation. This model provides valuable insight into the pathobiology of the disease, and will be helpful for trialing therapeutic compounds. © 2012 American Society for Bone and Mineral Research     

The cellular proliferative phase of the wound repair process

The proliferative--or new-tissue formation--phase of wound healing is complex. This article examines the changes that occur to cells during this stage and the effect on the extracellular matrix environment.     

The role of hyaluronic acid in wound healing's proliferative phase

This review discusses the multifaceted role of hyaluronic acid, focusing on the proliferative phase of wound healing. It considers the importance of achieving the right levels of this molecule, and the potential for future therapies.     

Ultrastructural evaluation of murine bladder epithelium exposed to verapamil

Summary The effect of single or multiple instillations of high verapamil concentrations on the cytoarchitecture of the bladder epithelium was assessed by electron microscopy. Ruthenium red was used to evaluate the surface mucopolysaccharide coats and the integrity of junctional complexes between luminal or nonluminal cells was found in any experimental animals, nor was there a breakdown of the junctional complexes between luminal cells. These data suggest that verapamil may be safely used intravesically as adjunct to standard chemotherapy.     

The protective role of G protein-coupled estrogen receptor 1 (GPER-1) on methotrexate-induced nephrotoxicity in human renal epithelium cells

Nephrotoxicity is an important problem during methotrexate (MTX) treatment, which has been widely used for the treatment of several cancer types. Females are less susceptible to kidney diseases; however, the reason for this condition has not to be fully clarified. But sex hormones such as estrogen may have a protective effect on the kidney. We aimed to evaluate the possible protective role of estrogen on the MTX-induced renal epithelial cell death. Primary renal proximal tubular epithelial cells (RPTEC) were incubated with MTX (1, 10 and 100?μM), either alone or in combination with the 17β-estradiol, G protein-coupled estrogen receptor 1 (GPER1) agonist G-1, estrogen receptor alpha agonist propyl pyrazole triol (PPT), estrogen receptor beta agonist diarylpropionitrile (DPN). Cell viability was determined by MTT assays. Interleukin (IL)-1β, IL-6, superoxide dismutase (SOD) and malondialdehyde (MDA) levels were determined in RPTEC. Approximately half of the cell death was observed with 10?μM MTX incubation for 48?h. The cell death was prevented by co-incubating with17β-estradiol, PPT and G-1. MTX was significantly induced IL-1β and IL-6.17β-estradiol, PPT and G-1 significantly decreased effects of MTX. SOD activity was significantly decreased treatment with MTX compared to control group. SOD activity was increased with co-incubation with 17β-estradioland G-1 compared to treatment with MTX. MDA levels significantly increased in treatment with MTX compared with the control group. Increased MDA levels by MTX-induced was decreased significantly by the treatment with 17β-estradiol and G-1. These data indicate that especially 17β-estradiol and G-1 may be useful in preventing undesirable effects of MTX in renal failure.     

普萘洛尔治疗增生期婴幼儿血管瘤的临床研究

目的：通过对普萘洛尔治疗婴幼儿血管瘤的临床研究,评估其治疗效果和安全性。方法：将我科从2009年9月至2010年8月收集的41例血管瘤患儿根据其家属的意见分为治疗组和观察组,其中治疗组20例,接受口服普萘洛尔治疗;观察组21例,接受门诊随访观察,比较两组的血管瘤变化情况,并检测治疗组服药前后患儿的心率、血糖、肝功能、肾功能、甲状腺功能等变化情况。结果：经过2个月的观察或治疗,治疗组显效9例,有效11例,无效0例;观察组显效0例,有效8例,无效13例。治疗组和观察组疗效有显著性差异,同时治疗组患儿治疗前与治疗后1h心率有所变化,其他如血糖和肝功能、肾功能及血FT3、FT4、sTSH等变化无明显统计学意义。结论：普萘洛尔在治疗婴幼儿血管瘤的过程中可抑制血管瘤的生长,部分患儿效果显著;治疗过程中不良反应少,安全性较高。     

Baohuoside-1 inhibits activated T cell proliferation at G(1)-S phase transition

BACKGROUND: The effect of baohuoside-1 (B1), a novel flavonoid, on cell proliferation and the cell cycle was evaluated in this study. METHODS: The antiproliferative properties of B1 were evaluated by proliferation assay. Western blotting and flow cytometric analysis were employed to investigate the expression of cyclins and cyclin-dependent kinase proteins. RESULTS: The major findings were (1) B1 effectively inhibited the cell proliferation activated by mitogenic antigen, with a 50% inhibitory concentration in low muM and in a dose- and time-dependent manner. (2) B1 resulted in G(1)-S phase cells arrest. (3) It down-regulated the expression of cyclin A, D and p33 cyclin-dependent kinase-2 (p33cdk2) proteins. (4) B1 suppressed the growth of several tumor cell lines. (5) B1 prevented rat heart allograft rejection in vivo. CONCLUSIONS: B1 immunosuppression of mitogen-activated T cell proliferation occurs in G(1)-S transition. It may be associated with the expression of cyclin A, D and p33cdk2 proteins. B1 prevents rat heart allograft rejection in vivo. The mechanism of B1 is different from tacrolimus and sirolimus.     

Expression of epidermal growth factor receptor and proliferative activity of cyst epithelium in human renal cystic diseases

Pathogenesis of malignancies in patients with polycystic kidney disease (PKD) is not clearly understood. Epidermal growth factor receptor (EGF-r) production by mature kidney plays a role in promotion of epithelial hyperplasia and cyst formation, its involvement in further progression is however not proven. Ki-67 is a marker for cellular proliferation. We assessed immunohistochemical expression of EGF-r and Ki-67 in epithelium of normal kidney, single cysts without PKD, epithelial tubular cells lining simple cysts and cysts with papillary proliferation in PKD patients, and analyzed the relationship with the occurrence of malignant tumors in these cases. 72% of PKD displayed EGF-r staining in epithelium lining cysts versus 33% in normal epithelium and 70% in epithelium of normal kidney. Ki-67 was increased in papillary cystic epithelium (24%) and in cysts lined by flat epithelium (66%). Renal cancers in PKD showed EGF-r staining in 33%, but no Ki-67 expression. EGF-r function and proliferative activity in cyst formation in PKD remains to be explored. EGF-r and Ki-67 expressions are not predictive of development of carcinoma in PKD.     

强脉冲光治疗增生期浅表草莓状血管瘤疗效观察

目的 观察强脉冲光（intense pulsed light,IPL）治疗婴幼儿增生期浅表草莓状血管瘤的治疗效果.方法 采用Queen IPL系统,选择合适的能量及间隔时间治疗68例婴幼儿增生期浅表草莓状血管瘤,并进行疗效评定.结果 总有效率为76.47%,少数患儿在治疗过程中出现水泡、色素沉着等不良反应.结论 IPL可以作为婴幼儿增生期浅表草莓状血管瘤的前期治疗方案.