Expression of Regulatory Homeobox Genes during Retina Regeneration in Adult Newts

We studied molecular-genetic mechanisms of retina regeneration in amphibians and, specifically, expression of the homeobox genes Pax6, Prox1, and Six3 in normal development and during retina regeneration in the newt. Based on the structural analysis of genes in closely related amphibian species, primers were constructed that flank certain regions of these genes. PCR fragments of calculated length were obtained. The relationship of PCR products to the above genes was confirmed by sequencing. A comparative PCR analysis of expression of Pax6, Prox1, and Six3 was carried out in the native and regenerating newt retina, which allowed estimation of the level of expression. cDNA libraries obtained from the native and regenerating retina were used as templates. The libraries were preliminary standardized according to glyceraldehydes-3-phosphate dehydrogenase, an enzyme of general cell metabolism. The genes we studied were expressed in both native and regenerating retina. The level of Pax6 and Prox1 expression increased during regeneration, while that of Six3 decreased. The decrease in the level of Six3 expression could be due to antagonistic interrelations of Prox1 and Six3. The changed level of Prox1 and Six3 expression is a new fact and requires further studies. The interactions between these and other regulatory genes and localization of their expression in the cells of native and regenerating retina will be studied using in situ hybridization and immunohistochemistry.     

The Causes of Necrobiosis and Apoptosis of Cornea Epithelial Cells during Primary Acquired Keratoconus Cornea

We studied 56 biopsy samples of conjunctiva and 50 corneal discs excised from 28 patients with acquired keratoconus cornea. The conjunctivas in all biopsy samples showed various stages of immune inflammation. Necrobiotic changes have been revealed in epithelium of the corneal discs going by the pathways of apoptosis—programmed cell death—and oncosis—initial edematic stage of necrobiosis. At the stage of acute inflammation they are due to cytotoxic effect of the lymphocytes, monocytes, and macrophages. Antibody-dependent cytotoxicity mediated by plasma and lymphoid cells predominates at this stage. At the reparative stage of inflammation ischemia, an inductor of apoptosis and oncosis, underlies necrobiotic changes in corneal epithelium.     

成体干细胞肺重建研究进展

成体干细胞来源广泛,无伦理争议,成为近几年的关注热点。研究表明以骨髓来源的间充质干细胞为代表的成体干细胞具有较强的多系分化潜能,可以广泛的参与包括肺在内的受损组织的修复与重建。在动物实验中已观察到,供体来源的成体干细胞可以定向分化为受损肺组织的多种功能细胞,并且有抑制纤维化等病变产生的能力。在本文中,回顾了近年来与肺损伤重建和疾病治疗相关的干细胞研究的最新进展,并探讨了成体干细胞治疗肺疾病与损伤的临床应用前景。     

Adult Stem Cells and Skeletal Repair and Regeneration

This article has no abstract.     

成人宫颈上皮细胞的原代培养及鉴定

目的:探索采用无血清培养基原代培养成人宫颈上皮细胞的方法。方法:以成人的宫颈上皮组织为研究对象,采用胰蛋白酶-EDTA消化法获得宫颈上皮细胞悬液,于上皮细胞专用无血清培养基中培养,采用免疫细胞化学法测定细胞中角蛋白及波形蛋白的表达,对细胞纯度进行鉴定。结果:原代培养10-15天细胞融合达60%,传代至4-6代,细胞出现生长衰退。早期细胞生长状态良好,细胞纯度在90%以上。结论:采用酶消化法及K-SFM无血清培养基培养可获得纯度高的成人宫颈上皮细胞。     

Fusion between Hematopoietic and Epithelial Cells in Adult Human Intestine

Following transplantation of hematopoietic lineage cells, genetic markers unique to the transplanted cells have been detected in non-hematopoietic recipient cells of human liver, vascular endothelium, intestinal epithelium and brain. The underlying mechanisms by which this occurs are unclear. Evidence from mice suggests it is due in part to fusion between cells of hematopoietic and non-hematopoietic origins; however, direct evidence for this in humans is scant. Here, by quantitative and statistical analysis of X- and Y-chromosome numbers in epithelial and non-epithelial intestinal cells from gender-mismatched hematopoietic cell transplant patients, we provide evidence that transplanted cells of the hematopoietic lineage incorporate into human intestinal epithelium through cell fusion. This is the first definitive identification of cell fusion between hematopoietic cells and any epithelial cell type in humans, and provides the basis for further understanding the physiological and potential pathological consequences of cell fusion in humans.     

Solute Transport Process in Intestinal Epithelial Cells

In rat small intestine, the active transport of organic solutes results in significant depolarization of the membrane potential measured in an epithelial cell with respect to a grounded mucosal solution and in an increase in the transepithelial potential difference. According to the analysis with an equivalent circuit model for the epithelium, the changes in emf's of mucosal and serosal membranes induced by active solute transport were calculated using the measured conductive parameters. The result indicates that the mucosal cell membrane depolarizes while the serosal cell membrane remarkably hyperpolarizes on the active solute transport. Corresponding results are derived from the calculations of emf's in a variety of intestines, using the data that have hitherto been reported. The hyperpolarization of serosal membrane induced by the active solute transport might be ascribed to activation of the serosal electrogenic sodium pump. In an attempt to determine the causative factors in mucosal membrane depolarization during active solute transport, cell water contents and ion concentrations were measured. The cell water content remarkably increased and, at the same time, intracellular monovalent ion concentrations significantly decreased with glucose transport. Net gain of glucose within the cell was estimated from the restraint of osmotic balance between intracellular and extracellular fluids. In contrast to the apparent decreases in intracellular Na⁺ and K⁺ concentrations, significant gains of Na⁺ and K⁺ occurred with glucose transport. The quantitative relationships among net gains of Na⁺, K⁺ and glucose during active glucose transport suggest that the coupling ratio between glucose and Na⁺ entry by the carrier mechanism on the mucosal membrane is approximately 1:1 and the coupling ratio between Na⁺-efflux and K⁺-influx of the serosal electrogenic sodium pump is approximately 4:3 in rat small intestine. In addition to the electrogenic ternary complex inflow across the mucosal cell membrane, the decreases in intracellular monovalent ion concentrations, the temporary formation of an osmotic pressure gradient across the cell membrane and the streaming potential induced by water inflow through negatively charged pores of the cell membrane in the course of an active solute transport in intestinal epithelial cells are apparently all possible causes of mucosal membrane depolarization.     

Cultivation and Characterization of Cornea Limbal Epithelial Stem Cells on Lens Capsule in Animal Material-Free Medium

A simple, reproducible, animal-material free method for cultivating and characterizing cornea limbal epithelial stem cells (LESCs) on human lens capsule (LC) was developed for future clinical transplantation. The limbal tissue explants (2×2×0.25 mm) were harvested from 77 cadavers and expanded ex vivo on either cell culture plates or LC in medium containing human serum as the only growth supplement. Cell outgrowth at the edge of the explants was observed within 24 hours of cultivation and achieved viable outgrowth (>97% viability as measured by MTT assay and flow cytometry) within two weeks. The outgrowing cells were examined by genome-wide microarray including markers of stemness (p63α, ABCG2, CK19, Vimentin and Integrin α9), proliferation (Ki-67), limbal epithelial cells (CK 8/18 and 14) and differentiated cornea epithelial cells (CK 3 and 12). Immunostaining revealed the non-hematopoietic, -endothelial and -mesenchymal stem cell phenotype of the LESCs and the localization of specific markers in situ. Cell adhesion molecules, integrins and lectin-based surface carbohydrate profiling showed a specific pattern on these cells, while colony-formation assay confirmed their clonal potency. The LESCs expressed a specific surface marker fingerprint (CD117/c-kit, CXCR4, CD144/VE-Cadherin, CD146/MCAM, CD166/ALCAM, and surface carbohydrates: WGA, ConA, RCA, PNA and AIL) which can be used for better localization of the limbal stem cell niche. In summary, we report a novel method combining the use of a medium with human serum as the only growth supplement with LC for cultivating, characterizing and expanding cornea LESCs from cadavers or alternatively from autologous donors for possible treatment of LESC deficiency.     

Changes in the Distribution of Fibronectin During Limb Regeneration in Newts Using Immunocytochemistry

The distribution of fibronectin in regenerating newt limbs was studied using immunocytochemistry. At appropriate intervals after the initial amputation at the elbow (10–30 days), animals were reamputated at the shoulder and processed for light microscopy. The peroxidase-antiperoxidase technique was used to localize affinity-purified antibodies to fibronectin in limb tissues. At the amputation site, fibronectin was associated with basal laminae and connective tissues adjacent to dedifferentiating limb tissues destined to form the regeneration blastema. Accumulation and growth of the blastema was accompanied by the apparent de novo synthesis of fibronectin, where it appeared randomly in the interstitium between blastemal cells. The onset of chondrogenesis was characterized by a central condensation of prechondroblasts that formed the cartilage anlagen. Fibronectin formed an amorphous network between presumptive chondroblasts. As the mature cartilage phenotype was expressed and chondrocytes became isolated in lacunae, fibronectin was greatly reduced and then disappeared. The extracellular matrix surrounding undifferentiated blastemal cells still contained fibronectin. Fibronectin was also found in high concentrations between differentiating myoblasts. A condensation of fibronectin was also observed beneath the epidermis at the distal limb tip at the onset of digit formation. These observations are consistent with the hypothesis that fibronectin may play a key role in the morphogenetic events that result in the spatial organization and subsequent differentiation of cells during pattern formation in the regenerating limb.     

通过整体消化法分离具有集落形成能力的胰腺上皮样细胞

目的:胰腺上皮细胞能诱导成表达胰岛素的细胞,成为细胞替代疗法治疗糖尿病的重要来源。胰腺细胞的分离多采用机械剪切后胶原酶消化,本文在以往研究基础上,探索一种能分离得到更纯净的胰腺上皮样细胞的新方法。方法:本研究采用胰腺整体消化的方法,将成体小鼠整个胰腺取下,摘除系膜及大的血管,置于胶原酶中消化20min,用PBS吹打胰腺组织,得到的细胞悬液,离心后去除上清与细胞碎片,用培养基重悬实质细胞,接种于6 cm培养皿中,培养7-10天后得到单细胞集落。结果:整体消化法不剪碎胰腺组织,从而避免多种胰腺细胞的参与,得到较为纯净的胰腺上皮细胞悬液,细胞总体数量小于部分消化法,但是单细胞比率远远高于部分消化法,得到的细胞集落更纯净,不需要去除成纤维细胞,方便筛选及进一步扩大培养。结论:整体消化法能够分离纯化出一群在离体条件下具有强增殖能力、形成大的上皮样集落的细胞。该分离方法方便、快捷,为今后进一步研究成体胰腺干细胞增殖与分化调控机制等问题奠定基础。     

Isolation and Culture of Dental Epithelial Stem Cells from the Adult Mouse Incisor

Understanding the cellular and molecular mechanisms that underlie tooth regeneration and renewal has become a topic of great interest^1-4, and the mouse incisor provides a model for these processes. This remarkable organ grows continuously throughout the animal''s life and generates all the necessary cell types from active pools of adult stem cells housed in the labial (toward the lip) and lingual (toward the tongue) cervical loop (CL) regions. Only the dental stem cells from the labial CL give rise to ameloblasts that generate enamel, the outer covering of teeth, on the labial surface. This asymmetric enamel formation allows abrasion at the incisor tip, and progenitors and stem cells in the proximal incisor ensure that the dental tissues are constantly replenished. The ability to isolate and grow these progenitor or stem cells in vitro allows their expansion and opens doors to numerous experiments not achievable in vivo, such as high throughput testing of potential stem cell regulatory factors. Here, we describe and demonstrate a reliable and consistent method to culture cells from the labial CL of the mouse incisor.     

Abnormal Limb Regeneration without Tumor Production in Adult Newts Directed by Carcinogens, 20-Methylcholanthrene and Benzo (α) pyrene

The effects of potent carcinogens, 20-methylcholanthrene (MC) and benzo(α)pyrene (BP), on limb regeneration were studied in adult newts. A microcrystal of these carcinogens was administered directly to the blastema of forelmibs on day 7 after amputation. The formation of the regeneration cone was delayed and the cone was shifted in abnormal polarity depending upon the site of micro-crystal administration. These carcinogens affected morphogenesis of skeletal structures of regenerating limbs. Subregeneration and superregeneration of either or both carpals and digits, absence of either or both ulna and radius, and accessory limb formation have been recorded as abnormalities caused by these carcinogens. Non-carcinogenic benzocompounds did not show such effects as those of MC and BP. The regeneration blastema of the limb appears to be resistant to carcinogenic effects of the carcinogens used since tumor formation has never been observed in our study so far.     

Mesenchymal Precursor Cells in Adult Nerves Contribute to Mammalian Tissue Repair and Regeneration

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Ecto-Mesenchymal Stem Cells from Facial Process: Potential for Muscle Regeneration

Ecto-mesenchymal stem cells (EMSCs) originate from the cranial neural crest and participate in the formation of tooth, salivary, and muscle in early development stage. The transplantation of EMSCs, a potential source of myoblast stem cell, might improve muscle regeneration. The purpose of this study was to explore whether EMSCs have the potential to differentiate and display a myogenic phenotype in vitro the in vitro. Here, we characterized the EMSCs isolated from the facial process, and p75 + EMSCs were collected by a FACS calibur flow cytometer. In vitro, p75 + EMSCs induced by DMSO can accumulate and fuse into multinucleated myotubes and further differentiate into the skeletal muscle cells in form of cell sheet. Functional myoblast phenotypes of p75 + EMSCs were found in vivo model of muscle injury. The remarkable ability of stem cells to regenerate skeletal muscle indicated their potential role in the cell therapy and tissue engineering of the skeletal muscle.     

Basolateral Cl- Transport Is Stimulated by Terbutaline in Adult Rat Alveolar Epithelial Cells

Stimulation of adult rat alveolar epithelial cells with terbutaline was previously shown to activate Cl- channels in the apical membrane. In this study, we show that terbutaline stimulates net transepithelial (apical-to-basolateral) Cl- absorption from 0.19 +/- 0.13 to 1.43 +/- 0.31 mmol x cm-2 x hr-1. Terbutaline also increases net Cl- efflux across the basolateral membrane under conditions where an outward [K+] gradient exists and the membrane voltage is clamped at zero mV. When the [K+] gradient is eliminated, the effect of terbutaline on net Cl- efflux is inhibited to the extent that no significant Cl- efflux can be detected across the basolateral membrane. RT-PCR experiments detected mRNA for three KCl cotransport isoforms (KCC1, KCC3 and KCC4) in monolayer cultures of alveolar epithelial cells. Western blot analysis using antibodies to the four cloned isoforms of KCl cotransporters revealed the presence of KCC1 and KCC4 isoforms in monolayer cultures of these cells. These results provide evidence suggesting a role for KCl cotransport in terbutaline-stimulated transepithelial Cl- absorption.     

A System for Culturing Iris Pigment Epithelial Cells to Study Lens Regeneration in Newt

Salamanders like newt and axolotl possess the ability to regenerate many of its lost body parts such as limbs, the tail with spinal cord, eye, brain, heart, the jaw ¹. Specifically, newts are unique for its lens regeneration capability. Upon lens removal, IPE cells of the dorsal iris transdifferentiate to lens cells and eventually form a new lens in about a month ^2,3. This property of regeneration is never exhibited by the ventral iris cells. The regeneration potential of the iris cells can be studied by making transplants of the in vitro cultured IPE cells. For the culture, the dorsal and ventral iris cells are first isolated from the eye and cultured separately for a time period of 2 weeks (Figure 1). These cultured cells are reaggregated and implanted back to the newt eye. Past studies have shown that the dorsal reaggregate maintains its lens forming capacity whereas the ventral aggregate does not form a lens, recapitulating, thus the in vivo process (Figure 2) ^4,5. This system of determining regeneration potential of dorsal and ventral iris cells is very useful in studying the role of genes and proteins involved in lens regeneration.     

Cues from Introduced Fish Alter Shelter Use and Feeding Behaviour in Adult Alpine Newts

Amphibians are particularly affected by alien fish introductions and are declining worldwide. However, the behavioural mechanisms behind the observed cases of coexistence and exclusion patterns between adult amphibians and fish are poorly understood. In the present study, we aimed at testing the hypothesis that adult newts display different feeding and space use behaviour in the presence of fish cues (i.e. access less food resources and use more shelters than when fish cues are absent). To achieve this we measured behavioural patterns in 100 adult Alpine newts (Mesotriton alpestris) in a replicated laboratory design (20 tanks × 7 replicates across time). Half of trials involved individuals in indirect (visual and olfactory) contact with goldfish (Carassius auratus), a non‐predatory species for adult newts. In the presence of fish, significantly more newts hid under shelters than in their absence, but this difference decreased over time. A lower number of newts fed in comparison with controls. These results show that newts responded to fish presence even in the absence of direct contact, but the differences were small. Newts decreased vital activities such as exploration of open areas and feeding. They also adjusted shelter use over time, suggesting a process of habituation or a risk assessment in the absence of direct risk. These results reveal that exploring behavioural patterns can aid in understanding the causes of exclusion and coexistence patterns between fish and amphibians.