Clinician’s guide to genes associated with Rett-like phenotypes—Investigation of a Danish cohort and review of the literature

The differential diagnostics in Rett syndrome has evolved with the development of next generation sequencing-based techniques and many patients have been diagnosed with other syndromes or variants in newly described genes where the associated phenotype(s) is yet to be fully explored. The term Rett-like refers to phenotypes with distinct overlapping features of Rett syndrome where the clinical criteria are not completely fulfilled. In this study we have combined a review of Rett-like disorders with data from a Danish cohort of 35 patients with Rett-like phenotypes emphasizing the diagnostic overlap with Pitt-Hopkins syndrome, Cornelia de Lange syndrome with SMC1A variants, and epileptic encephalopathies, for example, due to STXBP1 variants. We also found a patient with a pathogenic variant in KCNB1, which has not been previously linked to a Rett-like phenotype. This study underlines the clinical and genetic heterogeneity of a Rett syndrome spectrum, and provides an overview of the Rett syndrome-related genes described to date, and hence serves as a guide for diagnosing patients with Rett-like phenotypes.     

The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling

A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.     

巨噬细胞移动抑制因子在自发性高血压大鼠主动脉血管壁上的表达

目的：了解巨噬细胞移动抑制因子（MIF）与自发性高血压大鼠血管重构的关系。方法：观察不同周龄高血压大鼠（SHR）和SD大鼠主动脉的显微结构,采用免疫组化方法比较MIF在不同周龄SHR和SD大鼠主动脉的表达。结果：随着周龄增加,SHR主动脉中膜胶原纤维及弹性纤维相对面积比增加。主动脉平滑肌细胞（SMC）MIF阳性表达增多。结论：MIF可能与SHR血管重构有密切关系。     

Establishment of an Organic Model of SMC Proliferation with Cultured Aorta of Rats

Objective To study the mechanism of proliferous vascular disease as well as its prevention and treatment, an organic model was established with rat aorta. Methods The aorta segments of rats were cultured in vitro for 5, 8 and 13 days respectively. The proliferation of smooth muscle celI（SMC） was observed by HE staining and bromodeoxyuridine（Brdu） DNA labeling, and the expressions of hypertension-related gene- 1 （HRG- 1 ） and smooth muscle 22 alpha（SM22ct） mRNA was detected by RT-PCR. Results After being cultured 5 days in vitro, various degrees of proliferation of SMC on cultured artery segments was observed by HE staining and the conspicuous plaques were developed after being cultured 13 days. The nuclei of proliferous cells labeled by Brdu were seen under microscope. The expressions of HRG-1 and SM22amRNA decreased with prolonging of culture time and it completely disappeared after being cultured 13 days. Conclusion The results demonstrate that the culturing of rat aorta segments in vitro can induce the proliferation of SMC and the transformation of phenotype from contractile to synthesize type. This may be a good organic model that supplies a good experimental platform for us to research the mechanism of proliferous vascular disease as well as its prevention and treatment.     

不同内固定对肱骨干骨折愈合影响的影像学比较研究

目的：从影像学角度对天鹅记忆接骨器(SMC)、动力加压钢板(DCP)，交锁髓内钉(LIN)治疗肱骨干骨折的疗效进行前瞻性对比研究。方法：1998年2月～2002年3月，125例肱骨干骨折分别接受了上述3种内固定治疗，定期进行X线检查，观察骨折愈合情况，取出内固定后进行CT扫描。结果：DCP组骨痂出现较晚、量较少，骨折线消失最晚，骨折区域灰度密度积分及CT值较低；LIN组骨痂出现最早、量较多，骨折线消失较晚，骨折区灰度密度积分较高．骨折区域CT值较低；SMC组基本无骨痂出现，骨折线消失最早，并由板状骨直接替代，骨折区域灰度密度积分及CT值较高。结论：与DCP和LIN相比，SMC具有力学性能和几何构型上的优势，在促进骨折愈合的速度、方式及质量上有明显的优越性。     

Pro‐elastogenic effects of bone marrow mesenchymal stem cell‐derived smooth muscle cells on cultured aneurysmal smooth muscle cells

Abdominal aortic aneurysms (AAAs) involve slow proteolysis and loss of structural matrix components (collagen and elastin), which lead to wall thinning, weakening and ultimate rupture. At this time, no established non‐surgical therapy is available to slow or arrest AAA growth. Inhibiting matrix metalloproteases (MMPs; e.g. MMP2 and ?9) overexpressed within AAAs is insufficient to arrest AAA growth, since resident smooth muscle cells (SMCs) are poorly elastogenic and cannot overcome elastolysis to reinstate a healthy elastic matrix. Towards overcoming this limitation, this first study sought to determine the utility of rat bone marrow mesenchymal stem cell (BM‐MSC)‐derived SMCs to stimulate elastin and elastic matrix synthesis and assembly by aneurysmal SMCs (EaRASMCs). BM‐MSCs were successfully differentiated into cells of an SMC lineage (SMLCs). Our study indicates that BM‐MSC‐derived SMLCs secrete trophic factors, contained in conditioned medium (CM) from their cultures, that, when exposed to EaRASMC cultures in real time, stimulate elastin precursor and matrix deposition and crosslinking by these elastogenically deficient cells, with added benefits in terms of attenuating MMPs, specifically MMP9. The results thus lend support to a proposed cell therapy for AAAs, based on the use of BM‐MSC‐derived SMLCs. Although we observed no particular improvement in elastic fibre formation, no attenuation of MMP2 activity and increase in amounts of active MMP2 enzyme, we believe that this study justifies follow‐up studies to improve upon these outcomes. Future studies will explore the effects of concentrated CM collected from long‐term SMLC cultures on EaRASMCs and also investigate the elastogenic output of SMLCs themselves. Copyright © 2014 John Wiley & Sons, Ltd.     

miR-219a-5p对皮肤鳞状细胞癌细胞凋亡的影响及机制

目的探讨miR-219a-5p对皮肤鳞状细胞癌细胞凋亡的影响以及潜在的作用机制。方法设置miR-con组、miR-219a-5p组、anti-miR-con组、anti-miR-219a-5p组、miR-219a-5p+pcDNA组、miR-219a-5p+pcDNA-SMC4组、miR-con+SMC4-WT组、miR-con+SMC4-MT组、miR-219a-5p+SMC4-WT组、miR-219a-5p+SMC4-MT组,转染均用脂质体法。qRT-PCR检测miR-219a-5p和SMC4 mRNA表达水平;Western Blot检测蛋白表达;MTT法检测细胞增殖活性;流式细胞术检测细胞凋亡;双荧光素酶报告基因检测实验检测荧光活性。结果相较于人正常皮肤细胞HaCaT,皮肤鳞状细胞癌细胞HSC-2、Colo-16、SCL-1中SMC4 mRNA和蛋白表达水平显著升高,miR-219a-5p表达水平显著降低(P<0.05)。过表达miR-219a-5p可抑制皮肤鳞状细胞癌细胞增殖,诱导细胞凋亡;促进Caspase-3蛋白表达,抑制Cyclin D1蛋的表达;抑制Wnt/β-catenin信号通路激活。miR-219a-5p靶向负调控SMC4的表达,转染SMC4野生型表达载体的HSC-2细胞荧光素酶活性显著降低(P<0.05);而转染SMC4突变型表达载体的HSC-2细胞荧光素酶活性差异不显著。且过表达miR-219a-5p,SMC4表达水平显著降低;抑制miR-219a-5p表达,SMC4表达水平显著升高。过表达SMC4能逆转miR-219a-5p对皮肤鳞状细胞癌细胞HSC-2的增殖抑制和凋亡促进的作用。结论miR-219a-5p可抑制皮肤鳞状细胞癌细胞增殖,诱导细胞凋亡,其机制可能与Wnt/β-catenin及SMC4信号通路有关,将为皮肤鳞状细胞癌的预防和治疗提供新靶点。     

The structural maintenance of chromosomes (SMC) family of proteins in mammals

Structural maintenance of chromosomes (SMC) family proteins play critical roles in chromosome structural changes. SMC proteins are known to be involved in two major chromosome structural organization events required for mitotic segregation of chromosomes: mitotic chromosome condensation and sister chromatid cohesion. In eukaryotes, two separate sets of SMC heterodimers form the cores of two distinct multiprotein complexes termed condensin and cohesin, each specialized for condensation or cohesion, respectively. It is clear that both condensin and cohesin are conserved in mammals, including humans. The mammalian complexes demonstrate dynamic changes in intracellular distribution in a cell cycle-dependent manner. At any point in the cell cycle, the intracellular localization of the majority of mammalian cohesin and condensin appears to be complementary. Cohesin is associated with chromatin in interphase, while condensin is largely cytoplasmic. Similarly, in mitosis, cohesin is mostly excluded from chromosomes while condensin is distinctly bound to them. Cell cycle-dependent targeting of the two complexes appears to play a major role in regulating their cell cycle-specific activities, and how this redistribution is controlled is an area of active research. Finally, there is evidence that SMC proteins may be involved in DNA recombination and repair. This review focuses on what we have learned about SMC family proteins in humans and other mammalian species in comparison to those in lower eukaryotes. The authors present their own views with regard to some of the major outstanding questions surrounding the nature and functions of the SMC family of proteins.     

天鹅记忆接骨器对实验性骨折愈合过程中局部IGF-Ⅰ含量的影响

目的研究天鹅记忆接骨器（SMC）内固定对兔肱骨骨折愈合过程中局部IGF-Ⅰ的含量的影响,探讨SMC对骨折愈合过程的影响。方法随机选择兔一侧肱骨,截骨后SMC固定,为实验组。对侧肱骨同法截骨后,在相应位置用动力加压接骨板DCP固定,为对照组。术后第2、3、4、6、8、12周分别处死动物,以骨折线两侧0.5cm范围内为取材区。分别测定不同时间各组骨标本中IGF-Ⅰ含量。结果实验组骨折局部IGF-Ⅰ含量在术后2w逐渐增高,6w时达到顶峰,8～12wIGF-Ⅰ含量逐渐下降;DCP组骨折局部IGF-Ⅰ含量在术后2w逐渐增高,8w时达到顶峰,12周IGF-Ⅰ含量下降。两组间相比,术后3、4、6周,SMC组骨折局部IGF-Ⅰ含量明显高于DCP组,4周时差异最大。结论SMC较DCP更能促进骨折局部IGF-Ⅰ的分泌,促进骨折愈合。     

调肝导浊方对体外培养主动脉平滑肌细胞增殖影响的实验研究

为探讨中药调肝导浊方（由熟地黄,柴胡,草决明等组成）治疗动脉粥样硬化的机理,运用体外培养技术,培养大鼠主动脉平滑肌细胞（SMC）,以高脂血清以及加中药等不同培养基进行分组培养,取细胞进行指标检测,观察调肝导浊中药对主动脉SMC增殖的影响,结果：调肝导浊方能明显抑制高脂血清培养下SMC的增殖,其细胞增殖核抗原（PCNA）阳性率低于造模组（P＜0．01）。