Enteric neural differentiation in innervated,physiologically functional,smooth muscle constructs is modulated by bone morphogenic protein 2 secreted by sphincteric smooth muscle cells

The enteric nervous system (ENS) controls gastrointestinal (GI) functions, including motility and digestion, which are impaired in ENS disorders. Differentiation of enteric neurons is mediated by factors released by the gut mesenchyme, including smooth muscle cells (SMCs). SMC‐derived factors involved in adult enteric neural progenitor cells (NPCs) differentiation remain elusive. Furthermore, physiologically relevant in vitro models to investigate the innervations of various regions of the gut, such as the pylorus and lower oesophageal sphincter (LES), are not available. Here, neural differentiation in bioengineered innervated circular constructs composed of SMCs isolated from the internal anal sphincter (IAS), pylorus, LES and colon of rabbits was investigated. Additionally, SMC‐derived factors that induce neural differentiation were identified to optimize bioengineered construct innervations. Sphincteric and non‐sphincteric bioengineered constructs aligned circumferentially and SMCs maintained contractile phenotypes. Sphincteric constructs generated spontaneous basal tones. Higher levels of excitatory and inhibitory motor neuron differentiation and secretion of bone morphogenic protein 2 (BMP2) were observed in bioengineered, innervated, sphincteric constructs compared to non‐sphincteric constructs. The addition of BMP2 to non‐sphincteric colonic SMC constructs increased nitrergic innervations, and inhibition of BMP2 with noggin in sphincteric constructs decreased functional relaxation. These studies provide: (a) the first bioengineered innervated pylorus and LES constructs; (b) physiologically relevant models to investigate SMCs and adult NPCs interactions; and (c) evidence of the region‐specific effects of SMCs on neural differentiation mediated by BMP2. Furthermore, this study paves the way for the development of innervated bioengineered GI tissue constructs tailored to specific disorders and locations within the gut. Copyright © 2015 John Wiley & Sons, Ltd.     

Exploiting unique features of the gut-brain interface to combat gastrointestinal cancer

The gastrointestinal tract comprises a complex ecosystem with extensive opportunities for functional interactions between neoplastic epithelial cells and stromal, immune, neuronal, glial, and other cell types, as well as microorganisms and metabolites within the gut lumen. In this Review, we focus on interactions between gastrointestinal cancers and elements of the central and enteric nervous systems. This previously understudied but rapidly emerging area of investigation has blossomed in recent years, particularly with respect to improved understanding of neural contributions to the development and progression of esophageal, gastric, pancreatic, and colon neoplasia. Cancer neuroscience offers great promise to advance our understanding of how neural-cancer interactions promote alimentary tract neoplasia. The resulting mechanistic insights can be leveraged to identify diagnostic and prognostic biomarkers, and to develop novel therapeutic interventions.     

Transplanted progenitors generate functional enteric neurons in the postnatal colon

Cell therapy has the potential to treat gastrointestinal motility disorders caused by diseases of the enteric nervous system. Many studies have demonstrated that various stem/progenitor cells can give rise to functional neurons in the embryonic gut; however, it is not yet known whether transplanted neural progenitor cells can migrate, proliferate, and generate functional neurons in the postnatal bowel in vivo. We transplanted neurospheres generated from fetal and postnatal intestinal neural crest–derived cells into the colon of postnatal mice. The neurosphere-derived cells migrated, proliferated, and generated neurons and glial cells that formed ganglion-like clusters within the recipient colon. Graft-derived neurons exhibited morphological, neurochemical, and electrophysiological characteristics similar to those of enteric neurons; they received synaptic inputs; and their neurites projected to muscle layers and the enteric ganglia of the recipient mice. These findings show that transplanted enteric neural progenitor cells can generate functional enteric neurons in the postnatal bowel and advances the notion that cell therapy is a promising strategy for enteric neuropathies.     

A role for stem cell factor and c-kit in the murine intestinal tract secretory response to cholera toxin

The role of stem cell factor (SCF) and its receptor (c-kit) in the intestinal secretory response to cholera toxin (CT) was investigated using a ligated intestinal loop model in mice having mutations in the dominant white spotting (W) locus and the steel (Sl) locus. W/Wv mice, which express an aberrant form of the c-kit protein, failed to give an intestinal secretory response after luminal CT challenge. In contrast, W/Wv mice and their control littermates had equivalent intestinal secretory responses to Escherichia coli heat-stable enterotoxin (STa). Sl/Sld mice, which express only a soluble truncated form of SCF, also gave a significantly reduced intestinal secretory response to CT when compared to the secretory response of their littermate controls. The unresponsiveness of W/Wv mice to CT was restricted to the intestinal tract since these mice had foot pad swelling responses to CT challenge that were equivalent to their littermate controls. Restoration of mast cells in W/Wv mice by bone marrow transplantation of control littermate bone marrow did not reverse the CT-unresponsiveness of the intestinal tract. Histological evaluation of the gastrointestinal tract from W/Wv mice showed a normal distribution of enterochromaffin cells (ECC). CT challenge of either ligated intestinal loops from C57B1/6 mice or a mouse intestinal epithelial cell line (MODE-K) resulted in elevated levels of mRNA for SCF. MODE-K cells exposed to CT also had enhanced expression of c-kit. Finally, fluid obtained from CT-challenged ligated intestinal loops from C57B1/6 mice contained significant levels of SCF. Taken together, the above results suggest that CT-induced intestinal secretory responses are dependent upon SCF-c-kit interactions. These interactions appear to be induced as a consequence of CT stimulation of the intestinal tract and may also play a role in the development or functionality of the enteric nervous system.     

人类羊膜细胞表达神经干细胞特异性蛋白研究

目的利用神经干细胞特异性标志蛋白鉴定人类羊膜组织中多分化潜能神经前体细胞的存在.方法利用免疫组织化学法检测人类羊膜组织和培养人类羊膜细胞中巢蛋白(nestin)、胶质原纤维酸性蛋白(GFAP)、musashi-1、波形蛋白(vimentin)和PSA-NCAM等神经干细胞特异性标志蛋白的表达.结果人羊膜组织中存在nestin/GFAP双阳性细胞,此外,还表达musashi-1、vimentin和PSA-NCAM等神经干细胞特异性标志蛋白;培养羊膜细胞中存在vimentin和PSA-NCAM阳性细胞,以及nestin/GFAP双阳性细胞.结论羊膜组织和培养羊膜细胞中有神经干细胞特异性标记蛋白的表达.     

组织工程膀胱构建中生物支架材料及其性能评价

背景:利用肠道进行膀胱的修复和重建仍是进行膀胱替代的金标准.但是.由于肠道处在泌尿系的环境中,可能会引起代谢紊乱、感染、结石形成甚至恶变等一系列并发症.目的:总结评价组织工程膀胱构建中生物支架材料的性能,以寻找合理的膀胱替代物.方法:以"组织工程,膀胱,支架,间充质干细胞"为中文关键词,"tissue engineering,Bladder,Mesenchymal stem cells"为英文关键词,采用计算机检索1993-01/2009-10相关文章.纳入与有关种子细胞与组织工程膀胱相关及与膀胱生物支架材料相关的文章;排除重复研究或Meta分析类文章.以29篇文献为主,重点对一下5个问题进行了讨论:①如何稳定可靠迅速地获取充足的有活力的细胞源?②膀胱生物支架材料方面的选择?③修复重建膀胱的组织工程技术选择?④伦理学问题.⑤如何促进体外构建的膀胱组织植入体内后的快速血管化?结果与结论:采用自体间充质干细胞作为种子细胞应用于膀胱组织工程,不仅取材方便、具有低免疫原性,而且还可能分化为构建膀胱组织所必须的移行上皮细胞和平滑肌细胞以及血管内皮细胞、神经细胞从而改善再生组织的血供和神经功能,并能避免移植物纤维化挛缩,显示其独特的优越性,具有广阔的发展前景.但是,组织工程膀胱用于临床的有效性尚有待进一步评估,如组织工程膀胱与自体膀胱组织的愈合、结构和功能的重塑、血管化及神经支配的建立、伦理问题等重大难题都需要进一步研究.     

Emerging roles for enteric glia in gastrointestinal disorders

Enteric glia are important components of the enteric nervous system (ENS) and also form an extensive network in the mucosa of the gastrointestinal (GI) tract. Initially regarded as passive support cells, it is now clear that they are actively involved as cellular integrators in the control of motility and epithelial barrier function. Enteric glia form a cellular and molecular bridge between enteric nerves, enteroendocrine cells, immune cells, and epithelial cells, depending on their location. This Review highlights the role of enteric glia in GI motility disorders and in barrier and defense functions of the gut, notably in states of inflammation. It also discusses the involvement of enteric glia in neurological diseases that involve the GI tract.     

Gastrointestinal motility in acute illness

Critical illness affects gastrointestinal motility - not only as a primary problem, which brings the patient to the intensive care unit (ICU), but also as a complication consecutive to the ICU stay. Motility disturbances may result from impaired function of gastrointestinal muscle, pacemaker cell function and nerve activity. The most important neural control system is the enteric nervous system that contains the largest collection of neurons (10(8) cells) outside the central nervous system. Through its organization it can operate independently of the brain and generate motility patterns according to need: a postprandial motility pattern starting after food intake, and an interdigestive motility pattern starting several hours after a meal. Undisturbed intestinal motility depends critically on a balanced interaction between inhibition and excitation, and a disturbance in this balance leads to severe derangements of intestinal motility. These motility disturbances differ in clinical appearance and location but can affect all parts of the gastrointestinal tract. This review focuses on select motility disturbances such as gastroparesis, postoperative ileus, and Ogilvie's syndrome. Generally effective methods to treat these conditions are given. Finally, we focus on special management options to prevent such motility disturbances or to reduce their severity.     

A novel pathogenesis of megacolon in Ncx/Hox11L.1 deficient mice.

The Ncx/Hox11L.1 gene, a member of the Hox11 homeobox gene family, is mainly expressed in neural crest-derived tissues. To elucidate the role of Ncx/Hox11L.1, the gene has been inactivated in embryonic stem cells by homologous recombination. The homozygous mutant mice were viable. These mice developed megacolon with enteric ganglia by age 3-5 wk. Histochemical analysis of the ganglia revealed that the enteric neurons hyperinnervated in the narrow segment of megacolon. Some of these neuronal cells degenerated and neuronal cell death occurred in later stages. We propose that Ncx/Hox11L.1 is required for maintenance of proper functions of the enteric nervous system. These mutant mice can be used to elucidate a novel pathogenesis for human neuronal intestinal dysplasia.     

Trefoil peptides promote epithelial migration through a transforming growth factor beta-independent pathway.

The trefoil peptides, a recently recognized family of protease-resistant peptides, expressed in a regional specific pattern throughout the normal gastrointestinal tract. Although these peptides have been hypothesized to act as growth factors, their functional properties are largely unknown. Addition of recombinant trefoil peptides human spasmolytic polypeptide (HSP), rat and human intestinal trefoil factor (RITF and HITF) to subconfluent nontransformed rat intestinal epithelial cell lines (IEC-6 and IEC-17), human colon cancer-derived cell lines (HT-29 and CaCO2) or nontransformed fibroblasts (NRK and BHK) had no significant effect on proliferation. However addition of the trefoil peptides to wounded monolayers of confluent IEC-6 cells in an in vitro model of epithelial restitution resulted in a 3-6-fold increase in the rate of epithelial migration into the wound. Stimulation of restitution by the trefoil peptide HSP was enhanced in a cooperative fashion by the addition of mucin glycoproteins purified from the colon or small intestine of either rat or man, achieving up to a 15-fold enhancement in restitution. No synergistic effect was observed by the addition of nonmucin glycoproteins. In contrast to cytokine stimulation of intestinal epithelial cell restitution which is mediated through enhanced TGF beta bioactivity, trefoil peptide, and trefoil peptide-mucin glycoprotein stimulation of restitution was not associated with alteration in concentrations of bioactive TGF-beta and was not affected by the presence of immunoneutralizing anti-TGF beta antiserum. Collectively, these findings suggest that the trefoil peptides which are secreted onto the lumenal surface of the gastrointestinal tract may act in conjunction with the mucin glycoprotein products of goblet cells to promote reestablishment of mucosal integrity after injury through mechanisms distinct from those which may act at the basolateral pole of the epithelium.     

Intestinal barrier integrity and inflammatory bowel disease: Stem cell‐based approaches to regenerate the barrier

Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction proteins, along with a decreased expression of antimicrobial peptides. Inflammatory bowel disease is associated with life‐long morbidity for affected patients, and both the incidence and prevalence is increasing globally, resulting in substantial economic strain for society. Mucosal healing and re‐establishment of barrier integrity are associated with clinical remission, as well as with an improved patient outcome. Hence, these factors are vital treatment goals, which conventionally are achieved by a range of medical treatments, although none are effective in all patients, resulting in several patients still requiring surgery at some point. Therefore, novel treatment strategies to accomplish mucosal healing and to re‐establish normal barrier integrity in inflammatory bowel disease are warranted, and luminal stem cell‐based approaches might have an intriguing potential. Transplantation of in vitro expanded intestinal epithelial stem cells derived either directly from mucosal biopsies or from directed differentiation of human pluripotent stem cells may constitute complementary treatment options for patients with mucosal damage, as intestinal epithelial stem cells are multipotent and may give rise to all epithelial cell types of the intestine. This review provides the reader with a comprehensive state‐of‐the‐art overview of the intestinal barrier's role in healthy and diseased states, discussing the clinical application of stem cell‐based approaches to accomplish mucosal healing in inflammatory bowel disease.     

兔角膜缘上皮干细胞体外扩增及生物学鉴定

背景:角膜缘干细胞体外培养的关键在于建立稳定的体外培养体系,包括角膜缘干细胞的定位、培养条件、载体选择和鉴别方法等.目的:探索兔角膜缘上皮干细胞体外扩增方法,并对其生物学特性进行鉴定.方法:采用兔角膜缘组织块培养法,以人羊膜为载体,在体外进行兔角膜缘上皮干细胞原代和传代培养.倒置显微镜观察其体外生长特征;苏木精-伊红染色以及扫描电镜观察其形态;AE5和P63单克隆抗体免疫组织化学染色鉴定其蛋白表达.结果与结论:采用组织块培养法可在体外获得角膜缘上皮干细胞,能成功传代培养且保持较高增殖潜能.培养于去上皮羊膜上的干细胞可融合成片,呈"拉网"现象.原代角膜缘上皮干细胞AE5单克隆抗体染色阳性率低于5%,P63染色阳性达90%;随传代次数增加AE5染色阳性率增高,P63染色阳性率降低.结果显示兔角膜缘组织块培养法可以在体外成功获得角膜缘上皮干细胞,原代和传代细胞均具有干细胞特性,以羊膜为载体培养可形成角膜移植片.

Abstract：

BACKGROUND: How to establish a stable in vitro culture system, including location of corneal limbal epithelial stem cells, in vitro sample harvest, in vitro culture, vector selection, as well as identification methods, play a key role in corneal limbal epithelial stem cells culture. OBJECTIVE: To culture the isolated rabbit corneal limbal epithelial stem cells and to identify the biological properties of cultured cells. METHODS: The primary rabbit cornel limbal epithelial stem cells were isolated and cultured with tissue inoculation using human amniotic membrane as vector. The growth features of cells were observed under an inverted microscope. The morphology of cells was observed by hematoxylin-eosin staining and a scanning electron microscope. Furthermore, the monoclonal antibody AE5 and P63 two-step immunohistochemical staining were used to identify limbal epithelial stem cell protein expression. RESULTS AND CONCLUSION: The rabbit corneal limbal epithelial stem cells could be successfully cultured and maintained a relatively high value-added potential in vitro. Rabbit corneal limbal epithelial stem cells cultured on the amniotic membrane pull netted cellular layer. The AE5 monoclonal antibody positive rate of primary cultured cells was about 5% and P63 monoclonal antibody positive up to 90%. AE5-positive rate increased and P63-positive rate decreased with the increase in the number of subculture. The rabbit limbal epithelial stem cells can be successful culture and amplified on human amniotic membrane in vitro by limbal tissue culture method. The cultured cells maintain the characteristics of corneal epithelial cells. The rabbit corneal limbal epithelial stem cells can form grafts on the amniotic membrane.     

Experimental therapies for repair of the central nervous system: stem cells and tissue engineering

Several stem cell‐based therapeutic tools are currently being investigated for the regeneration of central nervous system (CNS) injuries. This review focuses on innovative approaches for CNS tissue repair via the use of implantable cellular devices. These devices are supported by biopharmaceuticals and conventional physiotherapy for the restoration of lost neuronal circuits and CNS function. This paper further reviews new and promising tools currently in pre‐clinical and clinical tests for the treatment of CNS diseases where substantial loss of cellular and extracellular components of neural tissue has occurred such as stroke, encephalopathy and traumatic neural injuries. We also discuss selected 3D bioscaffolds co‐cultured with clinically applicable human mesenchymal stem cells. Recent advances in neural tissue engineering and stem cell differentiation methods have shown promise for their clinical application in treating yet incurable CNS deficits. Copyright © 2012 John Wiley & Sons, Ltd.     

Neuroepithelial circuit formed by innervation of sensory enteroendocrine cells

Satiety and other core physiological functions are modulated by sensory signals arising from the surface of the gut. Luminal nutrients and bacteria stimulate epithelial biosensors called enteroendocrine cells. Despite being electrically excitable, enteroendocrine cells are generally thought to communicate indirectly with nerves through hormone secretion and not through direct cell-nerve contact. However, we recently uncovered in intestinal enteroendocrine cells a cytoplasmic process that we named neuropod. Here, we determined that neuropods provide a direct connection between enteroendocrine cells and neurons innervating the small intestine and colon. Using cell-specific transgenic mice to study neural circuits, we found that enteroendocrine cells have the necessary elements for neurotransmission, including expression of genes that encode pre-, post-, and transsynaptic proteins. This neuroepithelial circuit was reconstituted in vitro by coculturing single enteroendocrine cells with sensory neurons. We used a monosynaptic rabies virus to define the circuit’s functional connectivity in vivo and determined that delivery of this neurotropic virus into the colon lumen resulted in the infection of mucosal nerves through enteroendocrine cells. This neuroepithelial circuit can serve as both a sensory conduit for food and gut microbes to interact with the nervous system and a portal for viruses to enter the enteric and central nervous systems.     

Bioengineered lungs generated from human iPSCs‐derived epithelial cells on native extracellular matrix

The development of an alternative source for donor lungs would change the paradigm of lung transplantation. Recent studies have demonstrated the potential feasibility of using decellularized lungs as scaffolds for lung tissue regeneration and subsequent implantation. However, finding a reliable cell source and the ability to scale up for recellularization of the lung scaffold still remain significant challenges. To explore the possibility of regeneration of human lung tissue from stem cells in vitro, populations of lung progenitor cells were generated from human iPSCs. To explore the feasibility of producing engineered lungs from stem cells, we repopulated decellularized human lung and rat lungs with iPSC‐derived epithelial progenitor cells. The iPSCs‐derived epithelial progenitor cells lined the decellularized human lung and expressed most of the epithelial markers when were cultured in a lung bioreactor system. In decellularized rat lungs, these human‐derived cells attach and proliferate in a manner similar to what was observed in the decellularized human lung. Our results suggest that repopulation of lung matrix with iPSC‐derived lung epithelial cells may be a viable strategy for human lung regeneration and represents an important early step toward translation of this technology.     

兔角膜缘上皮干细胞体外扩增及生物学鉴定

背景：角膜缘干细胞体外培养的关键在于建立稳定的体外培养体系,包括角膜缘干细胞的定位、培养条件、载体选择和鉴别方法等。目的：探索兔角膜缘上皮干细胞体外扩增方法,并对其生物学特性进行鉴定。方法：采用兔角膜缘组织块培养法,以人羊膜为载体,在体外进行兔角膜缘上皮干细胞原代和传代培养。倒置显微镜观察其体外生长特征;苏木精-伊红染色以及扫描电镜观察其形态;AE5和P63单克隆抗体免疫组织化学染色鉴定其蛋白表达。结果与结论：采用组织块培养法可在体外获得角膜缘上皮干细胞,能成功传代培养且保持较高增殖潜能。培养于去上皮羊膜上的干细胞可融合成片,呈＂拉网＂现象。原代角膜缘上皮干细胞AE5单克隆抗体染色阳性率低于5%,P63染色阳性达90%;随传代次数增加AE5染色阳性率增高,P63染色阳性率降低。结果显示兔角膜缘组织块培养法可以在体外成功获得角膜缘上皮干细胞,原代和传代细胞均具有干细胞特性,以羊膜为载体培养可形成角膜移植片。     

MicroRNA‐132 directs human periodontal ligament‐derived neural crest stem cell neural differentiation

Neurogenesis is the basis of stem cell tissue engineering and regenerative medicine for central nervous system (CNS) disorders. We have established differentiation protocols to direct human periodontal ligament‐derived stem cells (PDLSCs) into neuronal lineage, and we recently isolated the neural crest subpopulation from PDLSCs, which are pluripotent in nature. Here, we report the neural differentiation potential of these periodontal ligament‐derived neural crest stem cells (NCSCs) as well as its microRNA (miRNA) regulatory mechanism and function in NCSC neural differentiation. NCSCs, treated with basic fibroblast growth factor and epidermal growth factor‐based differentiation medium for 24 days, expressed neuronal and glial markers (βIII‐tubulin, neurofilament, NeuN, neuron‐specific enolase, GFAP, and S100) and exhibited glutamate‐induced calcium responses. The global miRNA expression profiling identified 60 upregulated and 19 downregulated human miRNAs after neural differentiation, and the gene ontology analysis of the miRNA target genes confirmed the neuronal differentiation‐related biological functions. In addition, overexpression of miR‐132 in NCSCs promoted the expression of neuronal markers and downregulated ZEB2 protein expression. Our results suggested that the pluripotent NCSCs from human periodontal ligament can be directed into neural lineage, which demonstrate its potential in tissue engineering and regenerative medicine for CNS disorders.     

The gut as a neurological organ

We refer to the gut as a neurological organ to emphasize the particular importance of the nervous system in the regulation of digestive functions, given that the gastrointestinal tract is innervated by five different classes of neurons: intrinsic enteric neurons, vagal afferents, spinal afferents, parasympathetic efferents and sympathetic efferents. Virtually each aspect of digestive activity is under the regulatory influence of neurons, among which the enteric nervous system (ENS) plays the most important part. The ENS acts like a brain in the gut that functions independently of the central nervous system, contains programmes for a variety of gastrointestinal behaviours and governs the activity of all gastrointestinal effector systems according to need. Intrinsic sensory neurons supply the ENS with the kind of information that this system requires for its autonomic control of digestion, whereas extrinsic afferents notify the brain about any data that are relevant to energy and fluid homeostasis and the sensation of discomfort and pain. Many diseases of the gut, particularly the functional bowel disorders, seem to be related to dysfunction of the ENS and other components of the gastrointestinal innervation. The ENS and extrinsic afferents are hence prime targets for the therapeutic management of gut diseases and for the relief of the pain and discomfort associated with these disorders.     

A role for stem cell factor (SCF): c-kit interaction(s) in the intestinal tract response to Salmonella typhimurium infection

Cholera toxin (CT) has been shown to induce stem cell factor (SCF) production in mouse ligated intestinal loops. Further, SCF interaction(s) with its receptor (c-kit) was shown to be important for the intestinal tract secretory response after CT exposure. In this study, we have investigated whether SCF production is induced in the intestinal tract after exposure to Salmonella typhimurium and whether this production could be an important intestinal tract response to Salmonella infection. Using a mouse ligated intestinal loop model, increased levels of SCF mRNA were detected at 2-4 h post-Salmonella challenge. Intestinal fluid obtained from Salmonella-challenged loops contained high levels of SCF by ELISA. Human and murine intestinal epithelial cell lines were also shown to have increased levels of SCF mRNA after exposure to Salmonella. Inhibition of Salmonella invasion of epithelial cells was shown to be one potentially important role for SCF:c-kit interactions in host defense to Salmonella infection. Pretreatment of human or murine intestinal cell lines with SCF resulted in a cellular state that was resistant to Salmonella invasion. Finally, mice having mutations in the white spotting (W) locus, which encodes the SCF-receptor (c-kit), were significantly more susceptible to oral Salmonella challenge than their control littermates. Taken together, the above results suggest that an important intestinal tract response to Salmonella infection is an enhanced production of SCF and its subsequent interactions with c-kit.