BACKGROUND & AIMS: :Acute kidney injury is followed by regeneration of damaged renal tubular epithelial cells. The purpose of this study was to test the hypothesis that renal stem cells exist in the adult kidney and participate in the repair process. A unique population of cells that behave in a manner that is consistent with a renal stem cell were isolated from rat kidneys and were termed multipotent renal progenitor cells (MRPC). Features of these cells include spindle-shaped morphology; self-renewal for >200 population doublings without evidence for senescence; normal karyotype and DNA analysis; and expression of vimentin, CD90 (thy1.1), Pax-2, and Oct4 but not cytokeratin, MHC class I or II, or other markers of more differentiated cells. MRPC exhibit plasticity that is demonstrated by the ability of the cells to be induced to express endothelial, hepatocyte, and neural markers by reverse transcriptase-PCR and immunohistochemistry. The cells can differentiate into renal tubules when injected under the capsule of an uninjured kidney or intra-arterially after renal ischemia-reperfusion injury. Oct4 expression was seen in some tubular cells in the adult kidney, suggesting these cells may be candidate renal stem cells. It is proposed that MRPC participate in the regenerative response of the kidney to acute injury.

背景与目标： : 急性肾损伤后，受损的肾小管上皮细胞再生。目的检验肾干细胞存在于成人肾脏并参与修复过程的假说。从大鼠肾脏中分离出一种独特的细胞群，其行为方式与肾干细胞一致，被称为多能肾祖细胞 (MRPC)。这些细胞的特征包括梭形形态;> 200种群倍增的自我更新，没有衰老的证据; 正常的核型和DNA分析; 波形蛋白，CD90 (thy1.1)，Pax-2和10月4的表达，而不是细胞角蛋白，MHC I或II类，或更多分化细胞的其他标记。MRPC表现出可塑性，通过逆转录酶PCR和免疫组织化学诱导细胞表达内皮，肝细胞和神经标志物的能力证明了这种可塑性。当在未受伤的肾脏的胶囊下注射或在肾缺血再灌注损伤后动脉内注射时，细胞可以分化为肾小管。在成人肾脏的某些肾小管细胞中观察到10月4的表达，表明这些细胞可能是候选的肾干细胞。建议MRPC参与肾脏对急性损伤的再生反应。

BACKGROUND & AIMS: OBJECTIVE:The purpose of this study was to use serial thin-section CT scans to assess the incidence of respiratory viral infection and lung abnormalities in a large patient population at high risk of pulmonary complications. MATERIALS AND METHODS:The study population consisted of 26 recipients of hematopoietic stem cell transplants who had proven respiratory viral pneumonia. In all cases, thin-section CT scans were obtained before fiberoptic bronchoscopy and bronchoalveolar lavage. The study included only patients in whom bronchoalveolar lavage fluid showed no evidence of organisms other than respiratory viruses. The CT scans were assessed for the presence, extent, and anatomic distribution of ground-glass attenuation, air-space consolidation, nodules, centrilobular branching structures (tree-in-bud), thickening of the bronchovascular bundles, and pleural effusion. RESULTS:Areas of ground-glass attenuation were identified in 24 (92%) of 26 patients and were the only finding in eight patients. Multiple nodules, seen in 17 (65%) of 26 patients, measured 3-10 mm in diameter or were larger than 10 mm. The nodules had a centrilobular or random distribution. A tree-in-bud appearance was seen in six of the patients with centrilobular nodules. This pattern had a bilateral distribution and involved mainly the lower lung zones. CT revealed thickening of the bronchovascular bundles in 16 (61%) of the patients. Thickening was bilateral in 14 and unilateral in two patients. Bronchial wall thickening involved the lower lobes in six patients and had a patchy random distribution in the remaining nine patients. Air-space consolidation was present in nine (35%) of the cases. It had a lobular or subsegmental distribution in eight of the patients and a segmental distribution in one patient. Areas of consolidation were randomly distributed throughout the lungs in all cases. Less common findings included bilateral pleural effusion and bronchial dilatation. CONCLUSION:Respiratory viral infection is common among adult recipients of hematopoietic stem cell transplants, occurring over a wide time span after transplantation. The presence of respiratory viral infection must be considered in any patient with new respiratory symptoms, fever, or findings at CT such as extensive or patchy areas of ground-glass opacities or a mixture of patterns, most commonly ground-glass attenuation, thickening of the bronchial walls, and multiple small nodules.

背景与目标：

BACKGROUND & AIMS: BACKGROUND:The rodent specific reproductive homeobox (Rhox) gene cluster on the X chromosome has been reported to contain twelve homeobox-containing genes, Rhox1-12. RESULTS:We have identified a 40 kb genomic region within the Rhox cluster that is duplicated eight times in tandem resulting in the presence of eight paralogues of Rhox2 and Rhox3 and seven paralogues of Rhox4. Transcripts have been identified for the majority of these paralogues and all but three are predicted to produce full-length proteins with functional potential. We predict that there are a total of thirty-two Rhox genes at this genomic location, making it the most gene-rich homoeobox cluster identified in any species. From the 95% sequence similarity between the eight duplicated genomic regions and the synonymous substitution rate of the Rhox2, 3 and 4 paralogues we predict that the duplications occurred after divergence of mouse and rat and represent the youngest homoeobox cluster identified to date. Molecular evolutionary analysis reveals that this cluster is an actively evolving region with Rhox2 and 4 paralogues under diversifying selection and Rhox3 evolving neutrally. The biological importance of this duplication is emphasised by the identification of an important role for Rhox2 and Rhox4 in regulating the initial stages of embryonic stem (ES) cell differentiation. CONCLUSION:The gene rich Rhox cluster provides the mouse with significant biological novelty that we predict could provide a substrate for speciation. Moreover, this unique cluster may explain species differences in ES cell derivation and maintenance between mouse, rat and human.

背景与目标：

BACKGROUND & AIMS: PROBLEM:Lymphocyte immunotherapy (LIT) is applied in infertility treatment. Moreover, it has been suggested for prevention of rhesus D-hemolytic disease and as a vaccine for reduction of human immunodeficiency virus-1 susceptibility. Although transfusion-related problems have been rarely reported they were a matter of debate. Here we discuss extensive single-center experience with intradermal LIT for implantation failure and recurrent miscarriages. METHOD OF STUDY:Retrospective 2- to 3-year follow-up of in vitro fertilization couples treated during 1996-2002 (feedback 2,848/3,041 = 93%), registering 930 deliveries. Prospective survey for acute reactions for 2000-2003 (feedback 2,687/3,246 = 83%). Review of the literature. RESULTS:Infections of the patient and transplant rejection later in life are minor residual risks. Post-transfusion purpura was suspected once but not verified. Anaphylaxis or malignancy were not promoted. Fetal/newborn alloimmune disease (severe hemolytic disease, thrombocytopenia, neutropenia) were not observed. CONCLUSION:Based on microbiological, immunological, and hematological testing the risks of intradermal LIT are low.

背景与目标：

BACKGROUND & AIMS: :Thyroid hormone (TH) regulates such crucial biological functions as normal growth, development and metabolism of nearly all vertebrate tissues. In skeletal muscle, TH plays a critical role in regulating the function of satellite cells, the bona fide skeletal muscle stem cells. Deiodinases (D2 and D3) have been found to modulate the expression of various TH target genes in satellite cells. Regulation of the expression and activity of the deiodinases constitutes a cell-autonomous, pre-receptor mechanism that controls crucial steps during the various phases of myogenesis. Here, we review the roles of deiodinases in skeletal muscle stem cells, particularly in muscle homeostasis and upon regeneration. We focus on the role of T3 in stem cell functions and in commitment towards lineage progression. We also discuss how deiodinases might be therapeutically exploited to improve satellite-cell-mediated muscle repair in skeletal muscle disorders or injury.

背景与目标： : 甲状腺激素 (TH) 调节着几乎所有脊椎动物组织的正常生长，发育和代谢等关键的生物学功能。在骨骼肌中，TH在调节卫星细胞 (真正的骨骼肌干细胞) 的功能中起着至关重要的作用。已发现脱碘酶 (D2和D3) 调节卫星细胞中各种TH靶基因的表达。调节脱碘酶的表达和活性构成了一种细胞自主的前受体机制，该机制控制着肌发生各个阶段的关键步骤。在这里，我们回顾了脱碘酶在骨骼肌干细胞中的作用，特别是在肌肉稳态和再生中的作用。我们专注于T3在干细胞功能和对谱系进展的承诺中的作用。我们还讨论了如何在治疗上利用脱碘酶来改善骨骼肌疾病或损伤中的卫星细胞介导的肌肉修复。

BACKGROUND & AIMS: AIM:During development, boundary cap neural crest stem cells (bNCSCs) assist sensory axon growth into the spinal cord. Here we repositioned them to test if they assist regeneration of sensory axons in adult mice after dorsal root avulsion injury. MATERIALS & METHODS:Avulsed mice received bNCSC or human neural progenitor (hNP) cell transplants and their contributions to glial scar formation and sensory axon regeneration were analyzed with immunohistochemistry and transganglionic tracing. RESULTS:hNPs and bNCSCs form similar gaps in the glial scar, but unlike hNPs, bNCSCs contribute Mts1/S100A4 (calcium-binding protein) expression to the scar and do not assist sensory axon regeneration. CONCLUSION:bNCSC transplants contribute nonpermissive Mts1/S100A4-expressing cells to the glial scar after dorsal root avulsion.

背景与目标：

BACKGROUND & AIMS: :The unmet need for therapies capable of repairing the central nervous system (CNS) damage occurring in many diseases including multiple sclerosis (MS) has sparked the interest of the neurological community for stem cell-based therapies. An exhaustive amount of preclinical data has shown that the intravenous administration of mesenchymal stem cells (MSC), a subset of progenitor cells isolated from many mesodermal tissues, effectively ameliorates experimental autoimmune encephalomyelitis (EAE), a model of MS, through the release of anti-inflammatory and neuroprotective molecules. Based on these results, several small pilot clinical trials in subjects with advanced MS have demonstrated that MSC administration is safe and provided an early signal of clinical effectiveness. The current aim of clinicians and scientists interested in the development of MSC-based strategies for the treatment of MS is to have the ultimate demonstration in large clinical trials that MSC can inhibit CNS inflammation and foster tissue repair as realized clinically, with functional recovery, or visualized by magnetic resonance imaging (MRI).

背景与目标： : 对能够修复包括多发性硬化症 (MS) 在内的许多疾病中发生的中枢神经系统 (CNS) 损伤的疗法的未满足需求，引发了神经学界对基于干细胞的疗法的兴趣。大量的临床前数据表明，静脉内施用间充质干细胞 (MSC) (从许多中胚层组织中分离出的祖细胞的子集) 通过释放有效地改善了MS模型的实验性自身免疫性脑脊髓炎 (EAE) 炎症和神经保护分子。基于这些结果，在患有晚期MS的受试者中进行的一些小型试点临床试验表明，MSC给药是安全的，并提供了临床有效性的早期信号。对基于MSC的MS治疗策略的开发感兴趣的临床医生和科学家目前的目标是在大型临床试验中最终证明MSC可以抑制CNS炎症并促进组织修复，如临床实现的那样，具有功能恢复，或通过磁共振成像 (MRI) 可视化。

BACKGROUND & AIMS: :Upregulation of lipogenesis is a hallmark of cancer and blocking the lipogenic pathway is known to cause tumor cell death by apoptosis. However, the exact role of lipogenesis in tumor initiation is as yet poorly understood. We examined the expression profile of key lipogenic genes in clinical samples of ductal carcinoma in situ (DCIS) of breast cancer and found that these genes were significantly upregulated in DCIS. We also isolated cancer stem-like cells (CSCs) from DCIS.com cell line using cell surface markers (CS24(-)CD44(+)ESA(+)) and found that this cell population has significantly higher tumor-initiating ability to generate DCIS compared with the non-stem-like population. Furthermore, the CSCs showed significantly higher level of expression of all lipogenic genes than the counterpart population from non-tumorigenic breast cancer cell line, MCF10A. Importantly, ectopic expression of SREBP1, the master regulator of lipogenic genes, in MCF10A significantly enhanced lipogenesis in stem-like cells and promoted cell growth as well as mammosphere formation. Moreover, SREBP1 expression significantly increased the ability of cell survival of CSCs from MCF10AT, another cell line that is capable of generating DCIS, in mouse and in cell culture. These results indicate that upregulation of lipogenesis is a pre-requisite for DCIS formation by endowing the ability of cell survival. We have also shown that resveratrol was capable of blocking the lipogenic gene expression in CSCs and significantly suppressed their ability to generate DCIS in animals, which provides us with a strong rationale to use this agent for chemoprevention against DCIS.

背景与目标： : 脂肪生成的上调是癌症的标志，已知阻断脂肪生成途径会通过凋亡导致肿瘤细胞死亡。然而，脂肪生成在肿瘤起始中的确切作用尚不清楚。我们检查了乳腺癌导管原位癌 (DCIS) 临床样本中关键脂原基因的表达谱，发现这些基因在DCIS中显着上调。我们还使用细胞表面标记 (CS24(-)CD44(+)ESA(+)) 从DCIS.com细胞系中分离出癌症干细胞样细胞 (CSCs)，发现该细胞群与非干细胞样群体相比，产生DCIS的肿瘤起始能力明显更高。此外，与来自非致瘤性乳腺癌细胞系MCF10A的对应群体相比，CSCs显示出所有脂质基因的表达水平显着更高。重要的是，MCF10A中脂肪生成基因的主要调节剂SREBP1的异位表达显着增强了干细胞样细胞的脂肪生成，并促进了细胞生长和mammohere形成。此外，SREBP1的表达显着提高了MCF10AT (另一种能够产生DCIS的细胞系) 在小鼠和细胞培养中的CSCs的细胞存活能力。这些结果表明，通过赋予细胞存活能力，脂肪生成的上调是DCIS形成的先决条件。我们还表明，白藜芦醇能够阻断CSCs中的脂肪基因表达，并显着抑制其在动物中产生DCIS的能力，这为我们提供了使用该药物对DCIS进行化学预防的有力依据。

BACKGROUND & AIMS: :Satellite cells, localized within muscles in vivo, are Pax7+ muscle stem cells supporting skeletal muscle growth and regeneration. Unfortunately, their amplification in vitro, required for their therapeutic use, is associated with reduced regenerative potential. In the present study, we investigated if human myogenic reserve cells (MRC) obtained in vitro, represented a reliable cell source for muscle repair. For this purpose, primary human myoblasts were freshly isolated and expanded. After 2 days of differentiation, 62 ± 2.9% of the nuclei were localized in myotubes and 38 ± 2.9% in the mononucleated non-fusing MRC. Eighty percent of freshly isolated human MRC expressed a phenotype similar to human quiescent satellite cells (CD56+/Pax7+/MyoD-/Ki67- cells). Fourteen days and 21 days after cell transplantation in immunodeficient mice, live human cells were significantly more numerous and the percentage of Pax7+/human lamin A/C+ cells was 2 fold higher in muscles of animals injected with MRC compared to those injected with human myoblasts, despite that percentage of spectrin+ and lamin A/C+ human fibers in both groups MRC were similar. Taken together, these data provide evidence that MRC generated in vitro represent a promising source of cells for improving regeneration of injured skeletal muscles.

背景与目标： : 体内定位在肌肉内的卫星细胞是Pax7 + 肌肉干细胞，支持骨骼肌生长和再生。不幸的是，其治疗用途所需的体外扩增与再生潜力降低有关。在本研究中，我们研究了体外获得的人肌源性储备细胞 (MRC) 是否代表了用于肌肉修复的可靠细胞来源。为此，新鲜分离并扩增了原代人类成肌细胞。分化2天后，62个nuclei ±   2.9% 的细胞核位于肌管中，38个   ±   2.9% 位于单核非融合MRC中。80% 的新鲜分离的人MRC表达的表型类似于人静止卫星细胞 (CD56/Pax7/MyoD-/Ki67-细胞)。免疫缺陷小鼠细胞移植后14天和21天，活人细胞数量明显增加，注射MRC的动物肌肉中Pax7 +/人lamin A/C + 细胞的百分比比注射人成肌细胞高2倍，尽管两组MRC中spectrin和lamin A/C人类纤维的百分比相似。总之，这些数据提供了证据，表明体外产生的MRC代表了改善受损骨骼肌再生的有希望的细胞来源。

BACKGROUND & AIMS: :The expression of PD-L1 in breast cancer is associated with estrogen receptor negativity, chemoresistance and epithelial-to-mesenchymal transition (EMT), all of which are common features of a highly tumorigenic subpopulation of cancer cells termed cancer stem cells (CSCs). Hitherto, the expression and intrinsic role of PD-L1 in the dynamics of breast CSCs has not been investigated. To address this issue, we used transcriptomic datasets, proteomics and several in vitro and in vivo assays. Expression profiling of a large breast cancer dataset (530 patients) showed statistically significant correlation (p < 0.0001, r = 0.36) between PD-L1 expression and stemness score of breast cancer. Specific knockdown of PD-L1 using ShRNA revealed its critical role in the expression of the embryonic stem cell transcriptional factors: OCT-4A, Nanog and the stemness factor, BMI1. Conversely, these factors could be induced upon PD-L1 ectopic expression in cells that are normally PD-L1 negative. Global proteomic analysis hinted for the central role of AKT in the biology of PD-L1 expressing cells. Indeed, PD-L1 positive effect on OCT-4A and Nanog was dependent on AKT activation. Most importantly, downregulation of PD-L1 compromised the self-renewal capability of breast CSCs in vitro and in vivo as shown by tumorsphere formation assay and extreme limiting dilution assay, respectively. This study demonstrates a novel role for PD-L1 in sustaining stemness of breast cancer cells and identifies the subpopulation and its associated molecular pathways that would be targeted upon anti-PD-L1 therapy.

背景与目标： : PD-L1在乳腺癌中的表达与雌激素受体阴性，化学耐药性和上皮-间质转化 (EMT) 有关，所有这些都是称为癌症干细胞 (CSCs) 的高度致瘤性癌细胞亚群的共同特征。迄今为止，尚未研究PD-L1在乳腺CSCs动力学中的表达和内在作用。为了解决这个问题，我们使用了转录组数据集和蛋白质组学以及几种体外和体内测定。大乳腺癌数据集 (530例患者) 的表达谱显示，乳腺癌PD-L1表达与stemness评分有统计学意义 (p  <  0.0001，r   =   0.36)。使用ShRNA特异性敲低PD-L1揭示了其在胚胎干细胞转录因子: OCT-4A，Nanog和干性因子bmi1表达中的关键作用。相反，在通常PD-L1阴性的细胞中，PD-L1异位表达可诱导这些因子。全球蛋白质组学分析提示AKT在PD-L1表达细胞生物学中的核心作用。事实上，PD-L1对OCT-4A和Nanog的积极影响取决于AKT激活。最重要的是，如分别通过肿瘤球形成测定和极限稀释测定所示，PD-L1的下调损害了乳腺csc在体外和体内的自我更新能力。这项研究证明了PD-L1在维持乳腺癌细胞干性中的新作用，并确定了anti-PD-L1治疗靶向的亚群及其相关分子途径。

BACKGROUND & AIMS: :In Drosophila, the replacement of spent enterocytes (ECs) relies on division of intestinal stem cells (ISCs) and differentiation of their progeny, the enteroblasts (EBs). Recent studies have revealed a role for JAK/STAT signaling in the modulation of the rate of ISC division in response to environmental challenge. Here, we demonstrate the critical role of the UPD3 cytokine in the JAK/STAT-dependent response to enteric infection. We show that upd3 expression is activated in ECs and in EBs that massively differentiate in response to challenge. We show that the UPD3 cytokine, which is secreted basally and accumulates at the basement membrane, is required for stimulation of JAK/STAT signaling in EBs and visceral muscles (VMs). We further show that stimulation of ISC division requires active JAK/STAT signaling in EBs and VMs, but apparently not in ISCs. Our results suggest that EBs and VMs modulate the rate of the EGFR-dependent ISC division through upd3-dependent production of the EGF ligands Spitz and Vein, respectively. This study therefore supports the notion that the production of the UPD3 cytokine in stem cell progeny (ECs and EBs) stimulates intestinal stem cell division through modulation of JAK/STAT signaling in the stem cell microenvironment (EBs and VMs).

背景与目标： : 在果蝇中，用过的肠细胞 (ECs) 的替代依赖于肠干细胞 (isc) 的分裂及其后代，肠成细胞 (EBs) 的分化。最近的研究表明，JAK/STAT信号在响应环境挑战的ISC划分速率调节中的作用。在这里，我们证明了UPD3细胞因子在JAK/STAT依赖性肠道感染反应中的关键作用。我们证明了upd3表达在ECs和EBs中被激活，这些响应挑战而发生了巨大分化。我们表明，UPD3细胞因子是基底分泌并积聚在基底膜上的，是刺激EBs和内脏肌肉 (VMs) 中JAK/STAT信号传导所必需的。我们进一步表明，刺激ISC分区需要在EBs和vm中发出主动的JAK/STAT信号，但显然不在ISC中。我们的结果表明，EBs和VMs分别通过upd3-dependent产生EGF配体Spitz和静脉来调节EGFR依赖性ISC分裂的速率。因此，这项研究支持以下观点: 干细胞后代 (ECs和EBs) 中UPD3细胞因子的产生通过调节干细胞微环境 (EBs和VMs) 中的JAK/STAT信号来刺激肠道干细胞分裂。

BACKGROUND & AIMS: :This prospective study validates the finding from retrospective research that having an inpatient lay care-partner (CP) is associated with better survival following allogeneic BMT. Compared with patients without a CP (n=76), patients with a CP (n=88) have significantly better OS (P=0.017) and relapse-free survival (RFS) (P=0.020). Four-year and median survivals were 42% and 36 months among patients with CPs, compared with 26% and 10 months among those without CPs. Four-year survival and median RFS were 39% and 25 months among those with CPs, compared with 23% and 7 months among those without CPs. Further, better survival and RFS were associated with CP visit duration of >3 h per day (P=0.005 and P=0.007, respectively) and with CP frequency of visits >75% of inpatient days (P=0.004 and P=0.010, respectively). A CP support program should encourage not only presence of a CP but also duration and frequency of CP visits associated with better patient survival.

背景与目标： : 这项前瞻性研究证实了回顾性研究的发现，即拥有住院非专业护理伴侣 (CP) 与同种异体BMT后更好的生存率相关。与没有CP的患者 (n = 76) 相比，具有CP的患者 (n = 88) 具有明显更好的OS (P = 0.017) 和无复发生存率 (RFS) (P = 0.020)。CPs患者的4年和中位生存期分别为42% 和36个月，而无CPs的患者为26% 和10个月。患有CPs的患者的四年生存率和中位RFS分别为39% 和25个月，而没有CPs的患者为23% 和7个月。此外，更好的生存率和RFS与每天> 3 h的CP访视时间 (分别为P = 0.005和P = 0.007) 和CP访视频率> 住院天数的75% (分别为P = 0.004和P = 0.010) 相关。CP支持计划不仅应鼓励CP的存在，而且还应鼓励CP就诊的持续时间和频率与更好的患者生存率相关。

BACKGROUND & AIMS: OBJECTIVE:The intracellular signals that contribute to granulocyte colony-stimulating factor (G-CSF) receptor induced stem cell mobilization are poorly characterized. METHODS:We show enhanced G-CSF induced mobilization of stem cells in mice deficient in expression of Src family kinases (SFK-/-), which is associated with hypersensitivity of SFK-/- bone marrow cells to G-CSF as well as sustained activation of signal transducer and activator of transcription-3. RESULTS:A proteome map of the bone marrow fluid derived from wild-type and SFK-/- mice revealed a significant global reduction in the number of proteins in SFK-/- mice compared to controls, which was associated with elevated matrix metalloproteinase-9 levels, reduced stromal-derived factor-1 expression, and enhanced breakdown of vascular cell adhesion molecule-1. Transplantation of wild-type or SFK-/- stem cells into wild-type mice and treatment with G-CSF recapitulated the G-CSF-induced increase in stem cell mobilization noted in SFK-/- nontransplanted mice; however, the increase was significantly less. G-CSF treatment of SFK-/- mice engrafted with wild-type stem cells also demonstrated a modest increase in stem cell mobilization compared to controls, however, the observed increase was greatest in mice completely devoid of SFKs. CONCLUSIONS:These data suggest an involvement of both hematopoietic intrinsic and microenvironmental factors in Src kinase-mediated mobilization of stem cells and identify Src kinases as potential targets for modulating stem cell mobilization.

背景与目标：

BACKGROUND & AIMS: :Stem cells have been widely assumed to be capable of replacing lost or damaged cells in a number of diseases, including Parkinson's disease (PD), in which neurons of the substantia nigra (SN) die and fail to provide the neurotransmitter, dopamine (DA), to the striatum. We report that undifferentiated human neural stem cells (hNSCs) implanted into 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated Parkinsonian primates survived, migrated, and had a functional impact as assessed quantitatively by behavioral improvement in this DA-deficit model, in which Parkinsonian signs directly correlate to reduced DA levels. A small number of hNSC progeny differentiated into tyrosine hydroxylase (TH) and/or dopamine transporter (DAT) immunopositive cells, suggesting that the microenvironment within and around the lesioned adult host SN still permits development of a DA phenotype by responsive progenitor cells. A much larger number of hNSC-derived cells that did not express neuronal or DA markers was found arrayed along the persisting nigrostriatal path, juxtaposed with host cells. These hNSCs, which express DA-protective factors, were therefore well positioned to influence host TH+ cells and mediate other homeostatic adjustments, as reflected in a return to baseline endogenous neuronal number-to-size ratios, preservation of extant host nigrostriatal circuitry, and a normalizing effect on alpha-synuclein aggregation. We propose that multiple modes of reciprocal interaction between exogenous hNSCs and the pathological host milieu underlie the functional improvement observed in this model of PD.

背景与目标： : 人们普遍认为干细胞能够替代许多疾病中丢失或受损的细胞，包括帕金森氏病 (PD)，其中黑质 (SN) 的神经元死亡，无法向纹状体提供神经递质多巴胺 (DA)。我们报告了植入1-甲基-4-苯基-1,4，2,3-四氢吡啶处理的帕金森氏灵长类动物中的未分化人类神经干细胞 (hNSCs) 存活，迁移并通过行为改善定量评估具有功能影响在这个DA-缺陷模型中，其中帕金森氏征与DA水平降低直接相关。少数hNSC后代分化为酪氨酸羟化酶 (TH) 和/或多巴胺转运蛋白 (DAT) 免疫阳性细胞，这表明受损的成年宿主SN内部和周围的微环境仍允许通过反应性祖细胞发展DA表型。发现大量不表达神经元或DA标记的hNSC衍生细胞沿持续的黑质纹状体路径排列，与宿主细胞并列。因此，这些表达DA保护因子的hNSCs可以很好地影响宿主TH细胞并介导其他稳态调节，这反映在恢复到基线内源性神经元数量与大小之比，保留现存的宿主黑质纹状体回路以及对 α-突触核蛋白聚集的正常化作用。我们建议外源性hNSCs与病理性宿主环境之间相互作用的多种模式是该PD模型中观察到的功能改善的基础。

BACKGROUND & AIMS: :Control of self-renewal and differentiation of human ES cells (hESCs) remains a challenge. This is largely due to the use of culture systems that involve poorly defined animal products and do not mimic the normal developmental milieu. Routine protocols involve the propagation of hESCs on mouse fibroblast or human feeder layers, enzymatic cell removal, and spontaneous differentiation in cultures of embryoid bodies, and each of these steps involves significant variability of culture conditions. We report that a completely synthetic hydrogel matrix can support (i) long-term self-renewal of hESCs in the presence of conditioned medium from mouse embryonic fibroblast feeder layers, and (ii) direct cell differentiation. Hyaluronic acid (HA) hydrogels were selected because of the role of HA in early development and feeder layer cultures of hESCs and the controllability of hydrogel architecture, mechanics, and degradation. When encapsulated in 3D HA hydrogels (but not within other hydrogels or in monolayer cultures on HA), hESCs maintained their undifferentiated state, preserved their normal karyotype, and maintained their full differentiation capacity as indicated by embryoid body formation. Differentiation could be induced within the same hydrogel by simply altering soluble factors. We therefore propose that HA hydrogels, with their developmentally relevant composition and tunable physical properties, provide a unique microenvironment for the self-renewal and differentiation of hESCs.

背景与目标： : 控制人类胚胎干细胞的自我更新和分化仍然是一个挑战。这主要是由于使用了涉及定义不明确的动物产品且不模仿正常发育环境的培养系统。常规方案涉及hesc在小鼠成纤维细胞或人类饲养层上的繁殖，酶促细胞去除以及胚状体培养物中的自发分化，并且这些步骤中的每个步骤都涉及培养条件的显着变异性。我们报告说，完全合成的水凝胶基质可以支持 (i) 在来自小鼠胚胎成纤维细胞饲养层的条件培养基存在下hESCs的长期自我更新，以及 (ii) 直接细胞分化。之所以选择透明质酸 (HA) 水凝胶，是因为HA在hESCs的早期发育和饲养层培养中的作用以及水凝胶结构，力学和降解的可控性。当封装在3D HA水凝胶中 (但不在其他水凝胶中或在HA上的单层培养物中) 时，hESCs保持其未分化状态，保留其正常核型，并保持其完全分化能力，如胚状体形成所示。通过简单地改变可溶性因子，可以在同一水凝胶中诱导分化。因此，我们建议HA水凝胶具有与发育相关的组成和可调的物理特性，为hesc的自我更新和分化提供了独特的微环境。