The utilization of decellularized tendon slices to provide an inductive microenvironment for the proliferation and tenogenic differentiation of stem cells

The extracellular matrix (ECM) microenvironment for the stem cell niches, including but not limited to the biochemical composition, matrix topography, and stiffness, is crucial to stem cell proliferation and differentiation. The purpose of this study was to explore the capacity of the decellularized tendon slices (DTSs) to induce stem cell proliferation and tenogenic differentiation. Rat adult stem cells, including tendon-derived stem cells (TDSCs) and bone marrow-derived stem cells (BMSCs), were identified to have universal stem cell characteristics. The DTSs were found to retain the native tendon ECM microenvironment cues, including the inherent surface topography, well-preserved tendon ECM biochemical composition and similar stiffness to native tendon. When the TDSCs and BMSCs were cultured on the DTSs respectively, the LIVE/DEAD assay, alamarBlue^® assay, scanning electron microscopy examination and qRT-PCR analysis demonstrated that the DTSs have the capacity to support these stem cells homogeneous distribution, alignment, significant proliferation and tenogenic differentiation. Taken together, the findings of this study indicate that the DTSs can provide a naturally inductive microenvironment for the proliferation and tenogenic differentiation of TDSCs and BMSCs, supporting the use of decellularized tendon ECM as a promising and valuable approach for tendon repair/reconstruction.     

衰老大鼠模型骨髓基质细胞的生物学特点

目的探讨衰老大鼠骨髓基质细胞(BMSCs)的生物学特点,为阐释机体衰老对造血诱导微环境的影响提供实验依据。方法雄性健康SD大鼠随机分为正常组和衰老模型组。衰老模型组:大鼠皮下注射D-半乳糖120mg/kg,qd×42;正常对照组:大鼠皮下注射等时与等量生理盐水。衰老动物复制完成后第2天,分离骨髓单个核细胞(BMNCs)进行髓系造血祖细胞混合集落生成单位(CFU-Mix)培养。采用全骨髓贴壁法培养和传代BMSCs,取第3代细胞进行检测,CCK-8法测定BMSCs增殖能力;流式细胞术分析细胞周期;衰老相关β-半乳糖苷酶(SA-β-Gal)染色观察衰老BMSCs百分率;ELISA检测细胞培养上清液中白细胞介素(IL)-6、干细胞生长因子(SCF)含量;DCFH-DA荧光染色流式检测BMSC活性氧簇(ROS)水平;酶学法检测BMSCs内过氧化物丙二醛(MDA)含量和总超氧化物歧化酶(SOD)活性;Western blotting检测衰老相关蛋白P16、P21、P53表达。结果与对照组相比衰老模型组大鼠CFU-Mix集落形成数量明显降低;BMSCs增殖能力显著下降;处于G0/G1期的BMSCs比例增高、S期细胞比例降低,细胞阻滞于G1期;SA-β-Gal染色阳性的BMSCs百分率显著上升;BMSCs培养上清液中IL-6、SCF含量明显下降;BMSC内ROS、MDA氧化损伤指标上升,SOD抗氧化指标下降;衰老相关蛋白P16、P21、P53表达明显上调。结论衰老大鼠骨髓基质细胞表现衰老相关生物学改变,其机制可能与氧化损伤激活衰老信号通路有关。     

尿道下裂的细菌学研究

目的 探索尿道下裂术后的再造尿道易于感染的原因、感染源及细菌种类；据此改进围手术期处理措施，以降低感染率。方法 应用细菌培养鉴定、基因分型鉴定等从分子水平证实细菌的来源及种类。结果 经尿道外口逆行进入和再造尿道材料携带是细菌主要来源。引起尿道下裂感染主要是革兰氏阳性球菌。最有效抗生素是去甲万古霉素。结论 尿道下裂术后感染是切口感染而不是泌尿系感染。再造尿道感染率高于皮肤(黏膜)的原因在于造成了比体表更适合细菌生长繁殖的微环境。     

Tenascin-C induced signaling in cancer

Tenascin-C is an adhesion modulatory extracellular matrix molecule that is highly expressed in the microenvironment of most solid tumors. High tenascin-C expression reduces the prognosis of disease-free survival in patients with some cancers. The possible role of tenascin-C in tumor initiation and progression is addressed with emphasis on underlying signaling mechanisms. How tenascin-C affects malignant transformation, uncontrolled proliferation, angiogenesis, metastasis and escape from tumor immunosurveillance is summarized. Finally, we discuss how the phenotypes of tenascin-C knock-out mice may help define the roles of tenascin-C in tumorigenesis and how this knowledge could be applied to cancer therapy.     

骨髓间充质干细胞分化为光感受器样细胞的体外诱导和微环境研究

背景 近年来间充质干细胞(MSCs)在眼科方面已成功诱导分化为角膜细胞、视网膜神经节细胞(RGCs)、视网膜神经样细胞等,但诱导成为光感受器细胞及其微环境的研究尚少. 目的 研究骨髓MSCs(BMSCs)在体外定向分化为光感受器样细胞的可能性及其所需的微环境. 方法 分别将第2代BMSCs细胞株和视网膜色素上皮(RPE)细胞株进行常规培养和传代,取第4代人BMSCs细胞株及第3代RPE细胞株用于实验.将BMSCs分为诱导组和对照组,诱导组的BMSCs与含有20 μg/L碱性成纤维细胞生长因子(bFGF)、20 μg/L表皮生长因子(EGF)及20 μg/L脑源性神经营养因子(BDNF)的骨髓干细胞培养基(MSCM)及RPE细胞的条件培养液共培养进行BMSCs的诱导分化,而对照组的BMSCs仅用MSCM培养基进行培养,倒置显微镜下观察分化细胞的形态学变化.采用免疫细胞化学法检测RPE细胞诱导BMSCs3、5、7d时细胞中视紫红质蛋白的阳性表达率,以鉴定分化细胞的表型.采用逆转录PCR(RT-PCR)法检测RPE细胞诱导BMSCs 5 d、7d时细胞中视紫红质和恢复蛋白mRNA的表达情况. 结果 培养的BMSCs形态均一,呈纺锤形或梭形,RPE细胞形态均一,呈多边形或六边形,细胞内充满色素颗粒,生长良好.诱导后的部分BMSCs呈神经样细胞形态,细胞变圆,突起增长,突起末端可见一级、二级分支,相互间连接呈网状.免疫细胞化学法检测表明,诱导组细胞诱导后第3、5、7天细胞中可见视紫红质的表达,表达率分别为(5.83±0.29)％、(20.36±0.32)％和(29.80±2.30)％,明显高于对照组的(0.71±0.35)％、(2.56±0.24)％和(2.32±0.42)％,差异均有统计学意义(t3 d =41.510,ts d=107.290,t7 d=30.036,P＜0.01).RT-PCR法检测显示,诱导后5d、7d诱导组细胞中视紫红质和恢复蛋白mRNA表达的灰度值均明显高于对照组,差异均有统计学意义(视紫红质mRNA:ts d=103.506,t7 d=122.584,P＜0.01;恢复蛋白mRNA:t5 d=106.674,t7 d=189.992,P＜0.01). 结论 采用含bFGF、EGF及BDNF的条件培养基与RPE细胞培养液体外共培养后BMSCs能够诱导分化成光感受器样细胞.     

Oncostatin M Maintains the Hematopoietic Microenvironment and Retains Hematopoietic Progenitors in the Bone Marrow

Bone marrow (BM) functions as the primary hematopoietic tissue throughout adult life by providing a microenvironment for the proliferation, differentiation, and retention of hematopoietic stem cells and progenitors. We describe novel roles for oncostatin M (OSM) in the BM hematopoietic microenvironment. Hematopoietic progenitor activity in OSM-deficient mice was reduced in BM but elevated in the spleen and peripheral blood. The level of circulating granulocyte colony-stimulating factor (G-CSF) was increased, whereas that of stromal cell-derived factor 1 (SDF-1) was decreased in OSM-deficient mice. Moreover, the ability of OSM-deficient BM stromal cells to support hematopoiesis in vitro was significantly reduced. These results indicate that OSM plays a unique role in hematopoiesis by maintaining the proper microenvironment for BM hematopoiesis; it also retains hematopoietic progenitors in BM by regulating G-CSF and SDF-1 levels.     

Adipose-derived mesenchymal stem cells (ASCs) may favour breast cancer recurrence via HGF/c-Met signaling

Adipose tissue is a reservoir of Mesenchymal Stem Cells (Adipose-derived Mesenchymal Stem Cells, ASCs), endowed with regenerative properties. Fat graft was proposed for breast reconstruction in post-surgery cancer patients achieving good aesthetic results and tissues regeneration. However, recent findings highlight a potential tumorigenic role that ASCs may have in cancer recurrence, raising some concerns about their safety in clinical application.To address this issue, we established a model where autologous ASCs were combined with primary normal or cancer cells from breast of human donors, in order to evaluate potential effects of their interactions, in vitro and in vivo.Surprisingly, we found that ASCs are not tumorigenic per sè, as they are not able to induce a neoplastic transformation of normal mammary cells, however they could exhacerbate tumorigenic behaviour of c-Met-expressing breast cancer cells, creating an inflammatory microenvironment which sustained tumor growth and angiogenesis.Pharmacological c-Met inhibition showed that a HGF/c-Met crosstalk between ASCs and breast cancer cells enhanced tumor cells migration, acquiring a metastatic signature, and sustained tumor self-renewal.The master role of HGF/c-Met pathway in cancer recurrence was further confirmed by c-Met immunostaining in primary breast cancer from human donors, revealing a strong positivity in patients displaying a recurrent pathology after fat grafts and a weak/moderate staining in patients without signs of recurrence.Altogether our findings, for the first time, suggest c-Met expression, as predictive to evaluate risk of cancer recurrence after autologous fat graft in post-surgery breast cancer patients, increasing the safety of fat graft in clinical application.     

What is the Potential Interplay between Microbiome and Tumor Microenvironment in Oral Squamous Cell Carcinomas?

Oral cancer, with an around 50% mortality rate, is one of the most common malignancies world-wide. It is often detected in advanced or terminal stage and has a poor prognosis, although substantial progress in cancer management. Microbiome has become an increasingly recognized factor that may contribute to the cancerous development. Oral microbiological population comprising more than 700 bacterial species, varies since saliva and different habitats of oral cavity. A shift of composition of oral microbiome from usual condition to functional inflammation to pathological state has been discovered amongst patients with premalignant disorders and oral carcinoma, with evidence suggesting the tumor microenvironment (TME) could strongly exacerbate the influence of oral microorganisms. The complex interactions taking place in either cancer formation or progression have been evaluated in several publications, however given their results’ heterogeneity, a review is needed to correctly untangle the potential correlation in this group of pro-carcinogenesis. In this review, we briefly summarize our current knowledge of the role of oral microbiome, focusing on its potential crosstalk with TME in oral squamous cell carcinomas (OSCC) more precisely, and pave the way for manipulating oral microbiome to deal with OSCC in the future.