Primary Pathologic Change Research Articles

Exercise training upregulates CD55 to suppress complement-mediated synaptic phagocytosis in Parkinson’s disease

The primary pathological change in Parkinson’s disease (PD) is the progressive degeneration of dopaminergic neurons in the substantia nigra. Additionally, excessive microglial activation and synaptic loss are also typical features observed in PD samples. Exercise trainings have been proven to improve PD symptoms, delay the disease progression as well as affect excessive microglial synaptic phagocytosis. In this study, we established a mouse model of PD by injecting mouse-derived α-synuclein preformed fibrils (M-α-syn PFFs) into the substantia nigra, and demonstrated that treadmill exercise inhibits microglial activation and synaptic phagocytosis in striatum. Using RNA-Seq and proteomics, we also found that PD involves excessive activation of the complement pathway which is closely related to over-activation of microglia and abnormal synaptic function. More importantly, exercise training can inhibit complement levels and complement-mediated microglial phagocytosis of synapses. It is probably triggered by CD55, as we observed that CD55 in the striatum significantly increased after exercise training and up-regulation of that molecule rescued motor deficits of PD mice, accompanied with reduced microglial synaptic phagocytosis in the striatum. This research elucidated the interplay among microglia, complement, and synapses, and analyzed the effects of exercise training on these factors. Our work also suggested CD55 as a complement-relevant candidate molecule for developing therapeutic strategies of PD.Graphical

Bone morphogenetic protein 6 (BMP6) antagonises experimental proliferative vitreoretinopathy established by TGF-β2 stimulation in retinal pigment epithelial cells through modulation of the p38 and JNK MAPK pathways.

The formation of the epiretinal fibrotic membrane by retinal pigment epithelial (RPE) cells is a primary pathological change for proliferative vitreoretinopathy (PVR). Bone morphogenetic protein 6 (BMP6) is an antifibrogenic factor in various cells. To date, it is still unknown whether BMP6 can interfere with the fibrogenesis of RPE cells during the progression of PVR. This work aimed to address the relationship between BMP6 and transforming growth factor-β2 (TGF-β2)-elicited fibrogenesis of RPE cells, an experimental model for studying PVR in vitro. The BMP6 level was down-regulated, while the TGF-β2 level was up-regulated in the vitreous humor of PVR patients. The BMP6 level was down-regulated in human RPE cells challenged with TGF-β2. The treatment of RPE cells with TGF-β2 resulted in significant increases in proliferation, migration, epithelial-to-mesenchymal transition (EMT), and extracellular matrix (ECM) remodelling. These effects were found to be inhibited by the overexpression of BMP6 or exacerbated by the knockdown of BMP6. BMP6 overexpression reduced the phosphorylation of p38 and JNK in TGF-β2-stimulated RPE cells, while BMP6 knockdown showed the opposite effects. The inhibition of p38 or JNK partially reversed the BMP6-silencing-induced promoting effects on TGF-β2-elicited fibrogenesis in RPE cells. Taken together, BMP6 demonstrates the ability to counteract the proliferation, migration, EMT, and ECM remodelling of RPE cells induced by TGF-β2. This is achieved through the regulation of the p38 and JNK MAPK pathways. These findings imply a potential connection between BMP6 and PVR, and highlight the potential application of BMP6 in therapeutic interventions for PVR.

Lysophospholipid Acyltransferase 9 Promotes Emphysema Formation via Platelet-activating Factor.

Cigarette smoking is known to be the leading cause of chronic obstructive pulmonary disease (COPD). However, the detailed mechanisms have not been elucidated. PAF (platelet-activating factor), a potent inflammatory mediator, is involved in the pathogenesis of various respiratory diseases such as bronchial asthma and COPD. We focused on LPLAT9 (lysophospholipid acyltransferase 9), a biosynthetic enzyme of PAF, in the pathogenesis of COPD. LPLAT9 gene expression was observed in excised COPD lungs and single-cell RNA sequencing data of alveolar macrophages (AMs). LPLAT9 was predominant and upregulated in AMs, particularly monocyte-derived AMs, in patients with COPD. To identify the function of LPLAT9/PAF in AMs in the pathogenesis of COPD, we exposed systemic LPLAT9-knockout (LPALT9-/-) mice to cigarette smoke (CS). CS increased the number of AMs, especially the monocyte-derived fraction, which secreted MMP12 (matrix metalloprotease 12). Also, CS augmented LPLAT9 phosphorylation/activation on macrophages and, subsequently, PAF synthesis in the lung. The LPLAT9-/- mouse lung showed reduced PAF production after CS exposure. Intratracheal PAF administration accumulated AMs by increasing MCP1 (monocyte chemoattractant protein-1). After CS exposure, AM accumulation and subsequent pulmonary emphysema, a primary pathologic change of COPD, were reduced in LPALT9-/- mice compared with LPLAT9+/+ mice. Notably, these phenotypes were again worsened by LPLAT9+/+ bone marrow transplantation in LPALT9-/- mice. Thus, CS-induced LPLAT9 activation in monocyte-derived AMs aggravated pulmonary emphysema via PAF-induced further accumulation of AMs. These results suggest that PAF synthesized by LPLAT9 has an important role in the pathogenesis of COPD.

Alexander disease: The story behind an eponym

ABSTRACT In 1949, William Stewart Alexander (1919–2013), a young pathologist from New Zealand working in London, reported the neuropathological findings in a 15-month-old boy who had developed normally until the age of seven months, but thereafter had progressive enlargement of his head and severe developmental delay. The most striking neuropathological abnormality was the presence of numerous Rosenthal fibers in the brain. The distribution of these fibers suggested to Alexander that the primary pathological change involved astrocytes. In the next 15 years, five similar patients were reported, and in 1964 Friede recognized these cases reflected a single disease process and coined the eponym “Alexander’s disease” to describe the disorder. In the 1960s, electron microscopy confirmed that Rosenthal fibers were localized to astrocytes. In 2001, it was shown that Alexander disease is caused by mutations in the gene encoding glial fibrillary acidic protein, the major intermediate filament protein in astrocytes. Although the clinical, imaging, and pathological manifestations of Alexander disease are now well known, few people are familiar with Alexander’s career. Although he did not make a further contribution to the literature on Alexander disease, his observations and accurate interpretation of the neuropathology have justified the continued use of the eponym “Alexander disease.”

Integrative Analysis of Long Non-coding RNAs, Messenger RNAs, and MicroRNAs Indicates the Neurodevelopmental Dysfunction in the Hippocampus of Gut Microbiota-Dysbiosis Mice

Major depressive disorder is caused by gene–environment interactions and the gut microbiota plays a pivotal role in the development of depression. However, the underlying mechanisms remain elusive. Herein, the differentially expressed hippocampal long non-coding RNAs (lncRNAs), messenger RNAs (mRNAs), and microRNAs (miRNAs) between mice inoculated with gut microbiota from major depressive disorder patients or healthy controls were detected, to identify the effects of gut microbiota-dysbiosis on gene regulation patterns at the transcriptome level, and in further to explore the microbial-regulated pathological mechanisms of depression. As a result, 200 mRNAs, 358 lncRNAs, and 4 miRNAs were differentially expressed between the two groups. Functional analysis of these differential mRNAs indicated dysregulated inflammatory response to be the primary pathological change. Intersecting these differential mRNAs with targets of differentially expressed miRNAs identified 47 intersected mRNAs, which were mainly related to neurodevelopment. Additionally, a microbial-regulated lncRNA–miRNA–mRNA network based on RNA–RNA interactions was constructed. Subsequently, according to the competitive endogenous RNAs (ceRNA) hypothesis and the biological functions of these intersected genes, two neurodevelopmental ceRNA sub-networks implicating in depression were identified, one including two lncRNAs (4930417H01Rik and AI480526), one miRNA (mmu-miR-883b-3p) and two mRNAs (Adcy1 and Nr4a2), and the other including six lncRNAs (5930412G12Rik, 6430628N08Rik, A530013C23Rik, A930007I19Rik, Gm15489, and Gm16251), one miRNA (mmu-miR-377-3p) and three mRNAs (Six4, Stx16, and Ube3a), and these molecules could be recognized as potential genetic and epigenetic biomarkers in microbial-associated depression. This study provides new understanding of the pathogenesis of depression induced by gut microbiota-dysbiosis and may act as a theoretical basis for the development of gut microbiota-based antidepressants.

Clock knockdown attenuated reactive oxygen species-mediated senescence of chondrocytes through restoring autophagic flux

AimsArticular cartilage degeneration has been recognized as the primary pathological change in osteoarthritis (OA). Mechanisms that govern the shift from cartilage homeostasis to OA remain unknown. Previous studies have reported that intrinsic circadian clock in chondrocytes could function to optimize cartilage repair/remodeling to optimum times of day, but little is known about its molecular mechanisms. This study attempted to investigate the potential role and mechanism of circadian gene Clock in OA pathology. Materials and methodsThe expression of Clock in OA chondrocytes and cartilage was detected by qRT-PCR, western blot and immunohistochemistry. Temporal gene expression changes were analyzed using qRT-PCR in chondrocytes transfected with siClock following dexamethasone synchronization. In addition, the effect of Clock knockdown on senescent phenotypes and autophagic flux was evaluated in chondrocytes treated with siClock or siCntrl. Key findingsThe expression of Clock was up-regulated in OA cartilage from humans and mouse models. Clock knockdown had no influence on rhythmic expression of the downstream genes in primary chondrocytes. We also found that Clock knockdown elevated antioxidant enzyme activities, diminished reactive oxygen species (ROS) production and attenuated senescence of chondrocytes via restoring autophagic flux. SignificanceClock knockdown can attenuate ROS-mediated senescence of chondrocytes through restoring autophagic flux in non-circadian manner, providing a potential therapeutic target for OA.

SIRT5-Related Desuccinylation Modification Contributes to Quercetin-Induced Protection against Heart Failure and High-Glucose-Prompted Cardiomyocytes Injured through Regulation of Mitochondrial Quality Surveillance.

Myocardial fibrosis represents the primary pathological change associated with diabetic cardiomyopathy and heart failure, and it leads to decreased myocardial compliance with impaired cardiac diastolic and systolic function. Quercetin, an active ingredient in various medicinal plants, exerts therapeutic effects against cardiovascular diseases. Here, we investigate whether SIRT5- and IDH2-related desuccinylation is involved in the underlying mechanism of myocardial fibrosis in heart failure while exploring related therapeutic drugs for mitochondrial quality surveillance. Mouse models of myocardial fibrosis and heart failure, established by transverse aortic constriction (TAC), were administered with quercetin (50 mg/kg) daily for 4 weeks. HL-1 cells were pretreated with quercetin and treated with high glucose (30 mM) in vitro. Cardiac function, western blotting, quantitative PCR, enzyme-linked immunosorbent assay, and immunofluorescence analysis were employed to analyze mitochondrial quality surveillance, oxidative stress, and inflammatory response in myocardial cells, whereas IDH2 succinylation levels were detected using immunoprecipitation. Myocardial fibrosis and heart failure incidence increased after TAC, with abnormal cardiac ejection function. Following high-glucose treatment, HL-1 cell activity was inhibited, causing excess production of reactive oxygen species and inhibition of mitochondrial respiratory complex I/III activity and mitochondrial antioxidant enzyme activity, as well as increased oxidative stress and inflammatory response, imbalanced mitochondrial quality surveillance and homeostasis, and increased apoptosis. Quercetin inhibited myocardial fibrosis and improved cardiac function by increasing mitochondrial energy metabolism and regulating mitochondrial fusion/fission and mitochondrial biosynthesis while inhibiting the inflammatory response and oxidative stress injury. Additionally, TAC inhibited SIRT5 expression at the mitochondrial level and increased IDH2 succinylation. However, quercetin promoted the desuccinylation of IDH2 by increasing SIRT5 expression. Moreover, treatment with si-SIRT5 abolished the protective effect of quercetin on cell viability. Hence, quercetin may promote the desuccinylation of IDH2 through SIRT5, maintain mitochondrial homeostasis, protect mouse cardiomyocytes under inflammatory conditions, and improve myocardial fibrosis, thereby reducing the incidence of heart failure.

Metformin in cardiovascular diabetology: a focused review of its impact on endothelial function.

As a first-line treatment for diabetes, the insulin-sensitizing biguanide, metformin, regulates glucose levels and positively affects cardiovascular function in patients with diabetes and cardiovascular complications. Endothelial dysfunction (ED) represents the primary pathological change of multiple vascular diseases, because it causes decreased arterial plasticity, increased vascular resistance, reduced tissue perfusion and atherosclerosis. Caused by “biochemical injury”, ED is also an independent predictor of cardiovascular events. Accumulating evidence shows that metformin improves ED through liver kinase B1 (LKB1)/5'-adenosine monophosphat-activated protein kinase (AMPK) and AMPK-independent targets, including nuclear factor-kappa B (NF-κB), phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt), endothelial nitric oxide synthase (eNOS), sirtuin 1 (SIRT1), forkhead box O1 (FOXO1), krüppel-like factor 4 (KLF4) and krüppel-like factor 2 (KLF2). Evaluating the effects of metformin on endothelial cell functions would facilitate our understanding of the therapeutic potential of metformin in cardiovascular diabetology (including diabetes and its cardiovascular complications). This article reviews the physiological and pathological functions of endothelial cells and the intact endothelium, reviews the latest research of metformin in the treatment of diabetes and related cardiovascular complications, and focuses on the mechanism of action of metformin in regulating endothelial cell functions.

In situ hybridization revealed wide distribution of Haliotid herpesvirus 1 in infected small abalone, Haliotis diversicolor supertexta

Ganglioneuritis was the primary pathologic change in infected abalone associated with Haliotid herpesvirus 1 (HaHV-1) infection, which eventually became known as abalone viral ganglioneuritis (AVG). However, the distribution of HaHV-1 in the other tissues and organs of infected abalone has not been systemically investigated. In the present study, the distribution of HaHV-1-CN2003 variant in different organs of small abalone, Haliotis diversicolor supertexta, collected at seven different time points post experimental infection, was investigated with histopathological examination and in situ hybridization (ISH) of HaHV-1 DNA. ISH signals were first observed in pedal ganglia at 48 h post injection, and were consistently observed in this tissue of challenged abalone. At the same time, increased cellularity accompanied by ISH signals was observed in some peripheral ganglia of mantle and kidney. At the end of infection period, lesions and co-localized ISH signals in infiltrated cells were detected occasionally in the mantle and hepatopancreas. Transmission electron microscope analysis revealed the presence of herpes-like viral particles in haemocyte nuclei of infected abalone. Our results indicated that, although HaHV-1-CN2003 was primarily neurotropic, it could infect other tissues including haemocytes.

5-HT promotes pulmonary arterial smooth muscle cell proliferation through the TRPC channel

Pulmonary arterial hypertension is caused by an imbalance of pulmonary vasoconstriction and vasodilation. Pulmonary arteriolar remodeling is a primary pathological change and proliferation of pulmonary arterial smooth muscle cells (PASMC) is an important pathological basis for pulmonary arteriolar remodeling. Vasoactive substances, such as 5-HT, may play a role in proliferation of PASMC via unknown mechanisms. In vitro experiments with PASMC showed that the TRPC channel inhibitor SKF96365 inhibited the effects 5-HT and DOI on PASMC proliferation and G2M percentage increase, and decreased expression of TRPC1, TRPC6 and calcineurin A/NFATc3 induced by 5-HT and DOI. SKF96365 inhibited binding of NFATc3 and DNA promoted by 5-HT and DOI. Therefore, 5-HT may affect the TRPC channel to promote proliferation of PASMC; upregulate expression of TRPC1, TRPC6, and calcineurin A/NFATc3; and therefore promote NFATc3 nuclear translocation. There may be crosstalk between 5-HT and TRPC, which may contribute to the pathogeneis of pulmonary arterial hypertension and this may be a novel therapeutic target for treating pulmonary arterial hypertension.

Massive Brain Swelling and Death After Cranioplasty: A Systematic Review.

Although cranioplasty is a common procedure, it may cause a variety of complications. Massive brain swelling after cranioplasty (MBSC) is an unusual complication that has been reported more frequently in recent years. Most of the existing information about this condition is speculative and the cause remains unclear. A PubMed and Scopus search adhering to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed to include studies reporting patients with MBSC. Different information was analyzed in these cases to describe the characteristics and identify risk factors for MBSC. The search yielded 19 articles with a total of 26 patients. All studies were case reports and small case series. In most patients, preoperative intracranial hypotension and a considerable degree of sinking of skin flap were identified; this was the only constant finding observed in these cases. In addition, we propose a grading system to estimate the degree of preoperative sinking of skin flap and an algorithm with recommendations to decrease the incidence of MBSC. MBSC is an unusual, highly lethal, and probably underreported condition. The information gathered in this review indicates that MBSC occurs secondary to a cascade of pathologic events triggered by the bone flap implantation. This evidence suggests that the primary pathologic change is a sudden increase in the intracranial pressure acting on a brain chronically exposed to intracranial hypotension.

Effect of isopsoralen on Smad7 in osteoblastic MC3T3-E1 cells.

The primary pathological change in postmenopausal osteoporosis (PM-OP) is bone collagen loss caused by estrogen depletion. Osteoblasts synthesize type I collagen, which composes the organic matrix of bone. Although isopsoralen stimulates osteoblastic cell proliferation and differentiation, transforming growth factor (TGF)-β1 is an important cell signaling factor for stimulating collagen synthesis. To explore the association between isopsoralen and the synthesis of collagen in vitro, the molecular and biological association between isopsoralen and TGF-β signaling was examined. (CAGA) 12-luciferase-reporter gene was used to measure TGF-β1 signaling activity. Type I collagen was detected by semiquantitative reverse transcription polymerase chain reaction, and mothers against decapentaplegic homolog 7 (Smad7) protein expression levels were analyzed by western blotting. The expression of collagen in MC3T3-E1 cells stimulated with isopsoralen was significantly upregulated compared with the control groups (P<0.05). Conversely, isopsoralen significantly decreased Smad7 protein expression compared with the control groups (P<0.05). Moreover, it was observed that isopsoralen activates the TGF-β1 signaling pathway and ultimately promotes collagen synthesis through inhibition of Smad7 protein expression. Therefore, isopsoralen is a potential target for the treatment of PM-OP.

Effect of panax notoginseng saponins on pulmonary artery pathology of pulmonary hypertension rats

Objective To observe the effect of panax notoginseng saponins on pulmonary artery pathology in chronic hypoxic pulmonary hypertensionp (HPH) rats models, discuss the role and possible mechanisms of panax notoginseng saponins in prevention of chronic hypoxic pulmonary hypertension. Methods Forty male Sprague-Dawley (SD) rats were randomly divided into four groups (n=10). Group C: control group; Group H: rats were treated with hypoxia only; Group HC: rats were treated with hypoxia and captopril; and Group HP: rats were treated with hypoxia and panax notoginseng saponins. To observe the effect of panax notoginseng saponins prophylactic treatment in chronic hypoxic pulmonary hypertension rats, after the establishment of the model of hypoxic rat animal pulmonary hypertension models, transthoracic direct pulmonary artery intubation was measured in rat pulmonary arterial systolic pressure and mean pulmonary artery pressure, at the end of separation and cut for pulmonary artery to observe the pathological changes of pulmonary artery, results were recorded and statistically analyzed. Results ⑴Transthoracic direct pulmonary artery intubation was measured in rat pulmonary arterial systolic pressure and mean pulmonary artery pressure: pulmonary artery systolic pressure (PASP) and mean pulmonary arterial pressure (MPAP) were significantly higher in Group H than in Group C (P<0.05), Group HP was no significant difference relative to Group C. ⑵Pathological section shew that the primary pathological change of group H is vascular intimal hyperplasia and the proliferation of smooth muscle cells, medial hypertrophy, extracellular matrix increased, thickening of the vessel wall and the vascular stenos. Conclusions Panax notoginseng saponins inhibit the formation of chronic hypoxic pulmonary hypertension and pulmonary vascular remodeling in rats, and have the effect of prevention and treatment of pulmonary hypertension. Key words: SANCHINOSIDE/PD; Hypertension, pulmonary/DT/PA; Pulmonary artery/PA; Anoxia

MicroRNA-101 Inhibits Rat Cardiac Hypertrophy by Targeting Rab1a

Cardiac hypertrophy is a primary pathological change associated with cardiovascular diseases. Dysregulated microRNAs are frequent in cardiovascular diseases and contribute to cardiac hypertrophy by regulating a series of targeted genes. In this study, a rat model of cardiac hypertrophy was created by transverse abdominal aortic constriction, and cardiomyocyte hypertrophy in cultured neonatal rat cardiomyocytes was induced using angiotensin II (AngII) to investigate the role of miR-101 in myocardial hypertrophy. We demonstrated that miR-101 was downregulated in both the transverse abdominal aortic constriction rat model and hypertrophic cardiac myocytes. The overexpression of miR-101 in neonatal rat cardiomyocytes, which was accompanied by a reduced Rab1a level, inhibits 3 cardinal features of cardiomyocyte hypertrophy: fetal gene expression, protein synthesis, and cell enlargement. Conversely, the downregulation of miR-101 reverses these effects. Furthermore, the luciferase reporter system demonstrated that Rab1a is a target gene of miR-101, and the ectopic expression of Rab1a can reverse the cardiomyocyte hypertrophy inhibitory activity of miR-101. Taken together, our findings identify miR-101 as an important regulator in cardiac hypertrophy and implicate the potential application of miR-101 in the therapy of cardiac hypertrophy.

Morphology of retinal nerve fiber layer in diabetic patients by optical coherence tomography

Background Conventional studies showed that the primary pathological change of diabetic retinopathy (DR) is retinal microangiopathy.However,recent studies found that the disorder of visual function appears prior to retinal microangiopathy in diabetic patients.Thereby,this findings can not be explained by conventional view.Objective The aim of the study was to find the change of retinal nerve fiber layer (RNFL) by frequency domain optical coherence tomography(OCT) in the diabetic patients without retinal microangiopathy and with non-proliferative DR (NPDR) and investigate the relationship between the change of RNFL thickness and DR.Methods Sixty eyes of 56 patients with 2 type diabetes mellitus were enrolled in Shanxi Eye Hospital from October 2012 to September 2013.The patients were divided into the non-diabetic retinopathy (NDR) group (30 eyes of 26 patients) and NPDR group (30 eyes of 30 patients) depending on the findings of fundus fluorescine angiography (FFA) according to the DR International Clinical Classification System.Thirty normal eyes of 30 age-and gendermatched healthy volunteers were included as controls.RNFL thicknesses around optical disc and macular zone were measured by OCT,including average RNFL thickness in 360°,superior nasal,superior temporal,temporal,inferior temporal,inferior nasal and nasal RNFL thicknesses.The measuring results were compared between the three groups.Results The total average thickness values of RNFL around the optic disc for the NDR group,NPDR group and the control group were (97.46-± 8.65) μm,(100.69 ± 16.35) pm and (109.22 ± 8.69) μm,respectively,and the parameters in the NDR group and NPDR group were significantly lower than those in the normal control group (P=0.001,0.006).The RNFL thicknesses were thinning at the superior temporal,temporal,inferior temporal,inferior nasal quadrants around optical disc in NDR group compared with the normal control group (P=0.001,0.001,0.001,0.010),and RNFL thickness values of all the quadrants were decresed in the NPDR group compared with the normal control group,and significant differences were seen in superior temporal and nasal quadrants (P =0.001,0.046).The total average thickness values of RNFL around macular zone for the NDR group,NPDR group and the normal control group were (33.47±3.39),(36.81±3.21) and (38.18±2.16) μm,and parameters in the NDR group was significantly lower than that in the normal control group (P =0.001).The RNFL thicknesses of all the quadrants around macular zone in the NDR group were thinned in comparison with the normal control group (all at P＜0.01),and the RNFL thicknesses at the superior nasal,superior temporal and temporal quadrants were significantly decreased in comparison with the normal control group (P=0.026,0.015,0.001).Conclusions The thinning of the RNFL thickness occurs prior to retinal microangiopathy in diabetic patients,and it may be an early pathological stage for DR. Key words: Diabetes mellitus/complication; Retinopathy; Retinal nerve fiber layer; Visual function; Optical coherence tomography

Regulation mechanism and research progress of MeCP2 in Rett syndrome.

Rett syndrome (RTT) is an X-linked neurodevelopmental disease accountable for some of the severe mental retardation of females. Mutations in the gene encoding mythyl-CpG-binding protein 2, MeCP2, which acts as a suppressor of gene expression, are the primary genetic pathological change of RTT. Insufficient binding of MeCP2 with methylated DNA disrupts the proper expression of target genes and results in brain dysfunction. Currently, the proper role MeCP2 played in the process of brain development and the occurrence of RTT remain elusive. In this review, we summarize both the MECP2 gene and MeCP2 protein, with highlight upon their structures, functions and more importantly their regulatory mechanisms at the molecular level so as to elucidate the mechanisms underlying the pathogenesis of RTT.

Chemically Induced Specification of Retinal Ganglion Cells From Human Embryonic and Induced Pluripotent Stem Cells

The loss of retinal ganglion cells (RGCs) is the primary pathological change for many retinal degenerative diseases. Although there is currently no effective treatment for this group of diseases, cell transplantation to replace lost RGCs holds great potential. However, for the development of cell replacement therapy, better understanding of the molecular details involved in differentiating stem cells into RGCs is essential. In this study, a novel, stepwise chemical protocol is described for the differentiation of human embryonic stem cells and induced pluripotent stem cells into functional RGCs. Briefly, stem cells were differentiated into neural rosettes, which were then cultured with the Notch inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT). The expression of neural and RGC markers (BRN3A, BRN3B, ATOH7/Math5, γ-synuclein, Islet-1, and THY-1) was examined. Approximately 30% of the cell population obtained expressed the neuronal marker TUJ1 as well the RGC markers. Moreover, the differentiated RGCs generated action potentials and exhibited both spontaneous and evoked excitatory postsynaptic currents, indicating that functional and mature RGCs were generated. In combination, these data demonstrate that a single chemical (DAPT) can induce PAX6/RX-positive stem cells to undergo differentiation into functional RGCs.

Cytoprotective effects of urinary trypsin inhibitor on astrocytes injured by sustained compression

Decreased cell membrane integrity is a primary pathological change observed in traumatic brain injury (TBI) that activates a number of complex intercellular and intracellular pathological events, leading to further neural injury. In this paper, we assessed the effects of urinary trypsin inhibitor (UTI) on astrocyte membrane integrity by determining the percentage of lactate dehydrogenase (LDH) released after sustained compression injury using a hydrostatic pressure model of mechanical-like TBI. Astrocytes isolated from SD rat pups were injured by sustained compression. At a pressure of 0.3 MPa for 5 min, a significant increase in LDH release was observed compared with control samples. Astrocytes displayed extensive structural disruption of mitochondrial cristae reflected in their swelling. Based on our initial results, injured astrocytes were treated with UTI at a final concentration of 500, 1,000, 3,000 or 5,000 U/ml for 24 h. The percentage of LDH released from injured astrocytes was significantly decreased when 1,000 and 3,000 U/ml of UTI were used. In a separate experiment, astrocytes were treated with UTI at a final concentration of 1,000 U/ml immediately, or at 30 min, 2, 6, or 24 h after sustained compression. The percentage of LDH release was significantly reduced (P < 0.05) when astrocytes were treated with UTI immediately or 30 min later. Together, our results suggest that UTI may have protective effects on astrocytes injured by sustained compression injury. Furthermore, the early administration (<2 h after injury) of UTI may result in a better outcome compared with delayed administration.

Chemically-induced specification of retinal ganglion cells from human embryonic and induced pluripotent stem cells

The loss of retinal ganglion cells (RGCs) is the primary pathological change for many retinal degenerative diseases. Although there is currently no effective treatment for this group of diseases, cell transplantation to replace lost RGCs holds great potential. However, for the development of cell replacement therapy, better understanding of the molecular details involved in differentiating stem cells into RGCs is essential. In this study, a novel, stepwise chemical protocol is described for the differentiation of human embryonic stem cells and induced pluripotent stem cells into functional RGCs. Briefly, stem cells were differentiated into neural rosettes, which were then cultured with the Notch inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT). The expression of neural and RGC markers (BRN3A, BRN3B, ATOH7/Math5, γ-synuclein, Islet-1, and THY-1) was examined. Approximately 30% of the cell population obtained expressed the neuronal marker TUJ1 as well the RGC markers. Moreover, the differentiated RGCs generated action potentials and exhibited both spontaneous and evoked excitatory postsynaptic currents, indicating that functional and mature RGCs were generated. In combination, these data demonstrate that a single chemical (DAPT) can induce PAX6/RX-positive stem cells to undergo differentiation into functional RGCs.

P02 - 360 Magnetic resonance imaging study of basal ganglia in the first-episode tic disorders onset during child and adolescent

IntroductionDespite strong evidence that the pathophysiology of tic disorders (TD) involves structural and functional disturbances of the basal ganglia, inconsistent findings from several TD imaging studies have supported contradictory conclusions.ObjectiveTo find brain structural differences between children with of TD and the health children and verify the pathogenesis hypothesis of that basal ganglia play an important role in this disorder.MethodThe right handedness, first-episode TD children were chosen. Yale global tic severity scale (YGTSS) was used to assess the tic severity. MRI scan was performed on TD children and the controls. The volumes of caudate nucleus, putamen, globus pallidus and total intracranial volume were measured on high resolution MR images. We compared the volumes, relative volumes and asymmetry index, AI between groups.ResultsTotally 11 patients finished this study with two excluded for the unclear image caused by tic and 18 subjects (9 TD patients and 9 controls) were finally analyzed. The right globus pallidus is significantly larger in TD patients. The volumes of left caudate increased significantly in both TD patients and controls. There was no significant difference in asymmetry index between two groups, relative volumes did not correlate significantly with the severity of tic and the course of disease.ConclusionThe right globus pallidus may be the primary pathological change of TD. Asymmetry indexes between the two groups are not significantly different. The relative volume of any structure of basal ganglia has no significant correlation with the severity of tic and the course of disease.