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Biomedical subjects

Wei Shi

Publications and source records attributed to Wei Shi.

At least 19 recordsLinked to original sources

Calcium-Sensing Receptor Activation Disrupts Phosphatidylserine Asymmetry and Promotes Calcium Oxalate Crystal-Induced Epithelial Injury in Renal Tubular Epithelial Cells.

BACKGROUND: Calcium oxalate (CaOx) crystal retention on the renal tubular epithelium is a key step in urolithiasis. Phosphatidylserine (PS) exposure may facilitate crystal-cell adhesion, but the upstream signaling mechanisms and the relative contributions of impaired inward PS flipping versus outward PS redistribution remain unclear. MATERIALS AND METHODS: Global proteomic profiling using 2-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (2-DE/MALDI-TOF/TOF) in an immortalized human proximal tubular epithelial cell line (HK-2) cells exposed to calcium oxalate monohydrate (COM) identified upregulation of the calcium-sensing receptor (CaSR). HK-2 cells were treated with COM with or without the CaSR antagonist NPS2390 or the CaSR agonist gadolinium chloride (GdCl3). Bidirectional PS transport was assessed using an N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) (NBD)-labeled phosphatidylserine (NBD-PS) fluorescence-quenching assay, and surface PS exposure was measured by annexin V binding. Aminophospholipid translocase (APLT) expression, APLT-dependent inward PS transport, crystal adhesion, oxidative stress, and apoptosis-related signaling were evaluated. RESULTS: COM increased CaSR expression, enhanced surface PS exposure, and promoted crystal adhesion with concurrent oxidative stress and apoptosis-related signaling. COM induced a CaSR-sensitive defect in APLT-dependent inward PS flipping: NPS2390 partially restored inward PS transport and APLT expression, whereas GdCl3 exacerbated these changes. In contrast, COM-enhanced outward PS redistribution and externalization was largely unaffected by CaSR modulation, indicating relative CaSR insensitivity of the outward process. Consistently, CaSR activation aggravated, while CaSR inhibition attenuated, crystal adhesion and injury-related readouts. CONCLUSIONS: COM was associated with enhanced crystal-cell adhesion, CaSR activation, and a CaSR-sensitive impairment of APLT-dependent inward PS flipping, whereas enhanced outward PS redistribution appeared largely CaSR-insensitive. Pharmacologic inhibition of CaSR attenuated epithelial injury and crystal retention-related readouts, suggesting that CaSR may represent a potential therapeutic target.

Receptors, Calcium-Sensing↗

Systemic Proteomic Alterations and Predictive Biomarkers of Paroxetine Response in Refractory Rosacea: A Secondary Analysis of a Randomized Clinical Trial.

IMPORTANCE: Rosacea is a chronic inflammatory cutaneous disorder characterized by persistent erythema and vascular dysregulation. While paroxetine has shown clinical efficacy in reducing these symptoms, the systemic molecular mechanisms underlying its therapeutic response remain poorly characterized. OBJECTIVE: To investigate systemic proteomic alterations and identify potential predictive biomarkers in patients with refractory erythematous rosacea following paroxetine treatment. DESIGN, SETTING, AND PARTICIPANTS: This prospective plasma proteomic analysis was nested within a multicenter, randomized, double-blind, placebo-controlled clinical trial (Prospective Rosacea Refractory Erythema Randomized Clinical Trial [PRRERCT]). Participants included patients aged 18 to 65 years with refractory rosacea (Clinician's Erythema Assessment [CEA] score &#x2265;3). Plasma samples were collected at baseline and after 12 weeks of treatment. The data for this study were analyzed between September 2025 and November 2025. INTERVENTIONS: Participants received oral paroxetine, 25 mg per day, for a 12-week treatment period. MAIN OUTCOMES AND MEASURES: Systemic protein expression profiles were analyzed using data-independent acquisition liquid chromatography-tandem mass spectrometry. Clinical response was evaluated using CEA and the Flushing Assessment Tool. Correlations between proteomic changes and clinical improvements were assessed, and predictive biomarkers were identified using receiver operating characteristic curve analysis. RESULTS: Among 24 participants (mean [SD] age, 35 [11] years; 24 [100%] female), paroxetine treatment significantly reduced mean (SD) CEA scores from 3.1 (0.3) to 2.3 (0.7) and Flushing Assessment Tool scores from 3.1 (0.6) to 2.0 (0.9) (P&#x2009;<&#x2009;.001). Exploratory proteomic analysis revealed 497 candidate differentially expressed proteins after treatment. Downregulated proteins showed preliminary enrichment in pathways related to immune response activation, insulin receptor signaling, and neuronal remodeling. A subset of 98 reversed-response proteins was observed, primarily linked to synaptic vesicle cycles and vascular smooth muscle contraction. Proteomic alterations were associated with clinical improvement (65 proteins for erythema; 73 for flushing). Candidate biomarkers, notably OLFML3 (area under the receiver operating characteristic curve [AUC], 0.87 [95% CI, 0.70-1.00]) and IGFBP2 (AUC, 0.80 [95% CI 0.55-1.00]), demonstrated high predictive value for clinical response. CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial, paroxetine treatment was associated with modulation of systemic neuro-vascular-immune networks in patients with rosacea. These exploratory findings provide preliminary mechanistic clues regarding the possible disease-modifying potential of paroxetine and point to circulating protein signatures that may facilitate personalized therapeutic strategies for rosacea management. TRIAL REGISTRATION: Chinese Clinical Trial Registry Identifier: ChiCTR2000031479.

Humans↗

Deciphering the Microbiome-Gut-Eye Axis: A Mendelian Randomization Analysis of the Causal Influence of Gut Microbiota on Myopia.

INTRODUCTION: The intricate relationship between the gut microbiome and myopia is increasingly recognized, underscoring the need to explore its causal dynamics. Despite emerging evidence, the influence of Gut Microbiota (GM) on ocular development remains underexplored. METHODS: This study utilized Mendelian Randomization (MR) to investigate the causal impact of GM on the development of myopia. Instrumental variables (IVs) were identified from Genome-Wide Association Studies (GWAS), focusing on genetic variants significantly associated with microbiome composition. A comprehensive array of MR techniques was applied to ensure a robust estimation of causal effects and to adjust for potential confounders and pleiotropy. RESULTS: The Inverse-Variance Weighted (IVW) method was used to identify significant associations between GM and myopia. Increased risk of myopia was linked to the class Betaproteobacteria (OR=1.01, 95% CI 1.004-1.017, P=0.003), the order Burkholderiales (OR=1.009, 95% CI 1.001-1.016, P=0.02), the family Oxalobacteraceae (OR=1.005, 95% CI 1.001-1.01, P=0.023), and several genera including Eubacterium xylanophilum group (OR=1.007, 95% CI 1.001-1.013, P=0.033), and Bifidobacterium (OR=1.005, 95% CI 1-1.01, P=0.038). Protective effects were noted for the order Mollicutes RF9 (OR=0.994, 95% CI 0.99-0.999, P=0.014), the genus Allisonella (OR=0.996, 95% CI 0.993-0.999, P=0.019), the genus Lachnospiraceae UCG001 (OR=0.994, 95% CI 0.989-1, P=0.045), and the family Enterobacteraceae (OR=0.991, 95% CI 0.982-1, P=0.047) and order Enterobacteriales (OR=0.991, 95% CI 0.982-1, P=0.047). Sensitivity analyses further confirmed the robustness of these findings. DISCUSSION: This study provides causal evidence for the "Microbiome-Gut-Eye Axis" in myopia development, identifying specific gut microbiota that influence myopia risk. These findings suggest potential for microbiota-targeted interventions, warranting further research in diverse populations. CONCLUSIONS: The findings support the "Microbiome-Gut-Eye Axis" as a potential factor in myopia pathogenesis and highlight microbiota-targeted interventions as novel therapeutic strategies for managing myopia. This study lays the groundwork for further research on how modifying GM can influence eye health and offers new perspectives on preventive health strategies.

Humans↗

A novel molecular pathway of lipid accumulation in human hepatocytes caused by PFOA and PFOS.

Exposed to ubiquitously perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) has been associated with non-alcoholic fatty liver disease (NAFLD), yet the underlying molecular mechanism remains elusive. The extrapolation of empirical studies correlating per- and polyfluoroalkyl substance (PFAS) exposure with NAFLD occurrence to real-life exposure was hindered by the limited availability of mechanistic data at environmentally relevant concentrations. Herein, a novel pathway mediating hepatocyte lipid accumulation by PFOA and PFOS at human-relevant dose (<10&#xa0;&#x3bc;M) was identified by integrating CRISPR-Cas9 genome screening, concentration-dependent transcriptional assay in HepG2 cell and epidemiological data mining. 1) At genetic level, nudt7 showed the highest enriched potency among 569 NAFLD-related genes, and the transcription of nudt7 was significantly downregulated by PFOA and PFOS exposure (<7 &#x3bc;M). 2) At molecular pathway, upon exposure to&#xa0;&#x2264;10-4&#xa0;&#x3bc;M PFOA and PFOS, the downregulation of nudt7 transcriptional expression triggered the reduction of Ace-CoA hydrolase activity. 3) At cellular level, increased lipids were measured in HepG2 cells with PFOA and PFOS (<2&#xa0;&#x3bc;M). Overall, we identified a novel mechanism mediated by transcriptional downregulation of nudt7 gene in hepatocellular lipid increase treated with PFOA and PFOS, which could potentially explain the NAFLD occurrence associated with exposure to PFASs in humans.

Humans↗

[Efficacy and safety of coupled plasma filtration adsorption combined with continuous veno-venous hemofiltration for multiple organ dysfunction syndrome patients with acute liver failure].

OBJECTIVE: To evaluate efficacy and safety of coupled plasma filtration adsorption (CPFA) combined with continuous veno-venous hemofiltration (CVVH) for the treatment of multiple organ dysfunction syndrome (MODS) patients with acute liver failure (ALF), and to evaluate the effect of CPFA plus CVVF on inflammatory mediators in these patients. METHODS: A total of 38 cases of 11 MODS patients with ALF (male 6, female 5) were treated with CPFA plus CVVH, and the following clinical indicators including changes in mean arterial pressure (MAP), oxygen index (PaO(2)/FiO(2)), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-6, IL-8, biochemical parameters of liver and kidney function, parameters of systemic inflammatory response syndrome (SIRS) score, and acute physiology and chronic health evaluation II (APACHE II) score were determined before and after the treatment. The degree of improvement in clinical symptoms, feasibility, tolerance toward CPFA plus CVVH, therapy-related adverse reactions and security were simultaneously evaluated. RESULTS: MAP increased by 12 mmHg (1 mmHg=0.133 kPa), and PaO(2)/FiO(2) increased by 40 mmHg after the application of CPFA plus CVVH (both P<0.05), along with significant decrease in TNF-alpha, IL-1 beta, IL-6, IL-8 and markedly lowered levels of serum total bilirubin (IBIL), direct bilirubin (DBIL), blood urea nitrogen (BUN), serum creatinine (SCr) and blood ammonia (all P<0.05). Besides, clinical symptoms, including urinary volume, mental disturbance, jaundice, debility, nausea, vomiting, fever, abdominal distention, anepithymia, and SIRS, APACHE II scores were improved significantly after the CPFA plus CVVH (all P<0.05). No therapy-related adverse reactions, including severe haemorrhage, shock, hypersensitivity, were noted, and patients tolerated well toward CPFA plus CVVH. The total survival rate of patients was 45.5% (5/11 cases) at the end of the treatment. CONCLUSION: Our data indicate that CPFA combined with CVVH is an effective and safe method to improve the prognosis of MODS patients with ALF, the mechanism of which may be related to its effective removal of inflammatory cytokines.

Adult↗

Frequency distribution of TATA Box and extension sequences on human promoters.

BACKGROUND: TATA box is one of the most important transcription factor binding sites. But the exact sequences of TATA box are still not very clear. RESULTS: In this study, we conduct a dedicated analysis on the frequency distribution of TATA Box and its extension sequences on human promoters. Sixteen TATA elements derived from the TATA Box motif, TATAWAWN, are classified into three distribution patterns: peak, bottom-peak, and bottom. Fourteen TATA extension sequences are predicted to be the new TATA Box elements due to their high motif factors, which indicate their statistical significance. Statistical analysis on the promoters of mice, zebrafish and drosophila melanogaster verifies seven of these elements. It is also observed that the distribution of TATA elements on the promoters of housekeeping genes are very similar with their distribution on the promoters of tissue specific genes in human. CONCLUSION: The dedicated statistical analysis on TATA box and its extension sequences yields new TATA elements. The statistical significance of these elements has been verified on random data sets by calculating their p values.

Base Sequence↗

Multiple dysregulated pathways in nasopharyngeal carcinoma revealed by gene expression profiling.

Gene expression profiling was conducted using primary human nasopharyngeal carcinoma (NPC) biopsy samples to improve the understanding of the molecular pathways defining NPC and to identify novel potential therapeutic targets. RNA samples were extracted from 36 patients suspected to have NPC and hybridized onto the Affymetrix U133A chip. NPC was diagnosed in 19 patients, 11 had lymphoid hyperplasia (LH), and 6 were "normal" biopsies. Clinical stages for these NPC patients ranged from I-IV, including one M1. All NPC patients (except the M1) were treated with curative intent, which included radiotherapy alone (4 patients), or combined with chemotherapy (14 patients). Unsupervised clustering demonstrated a distinct NPC expression pattern, compared to normal biopsies. Subsequent Significance Analysis of Microarrays (SAM) derived from 14 NPC and 6 normal samples discovered 1,089 differentially regulated genes. Pathway analyses revealed novel insights into the mechanisms leading to NPC, whereby upregulation of NFkappaB2 and survivin play central roles in increasing resistance to apoptosis, and changes in integrin and WNT/beta-catenin signaling leading to uncontrolled proliferation. The role of survivin in resisting apoptosis in NPC was confirmed by RNA interference. Our data provide novel insights into the development and progression of NPC, and suggest survivin as a novel therapeutic target for NPC.

Apoptosis↗

Prognostic significance of the Epstein-Barr virus, p53, Bcl-2, and survivin in nasopharyngeal cancer.

PURPOSE: Nasopharyngeal cancer (NPC) is a malignant epithelial carcinoma which is intimately associated with EBV. The latent presence of EBV affects the function of p53, Bcl-2, and survivin. We thus investigated the relationship between EBV status, p53, Bcl-2, and survivin in biopsy specimens from patients with primary NPC. EXPERIMENTAL DESIGN: Archival formalin-fixed, paraffin-embedded NPC biopsies were evaluated in 80 patients treated with curative radiation from a single institution. The presence of EBV was determined using EBER in situ hybridization, whereas p53, Bcl-2, and survivin were assessed using immunohistochemistry. RESULTS: The majority of NPC specimens in this patient cohort were EBER-positive (64 of 78, or 82%), which in turn, was significantly associated with ethnicity (P = 0.0007), and WHO subtype 2A/2B (P = 0.04). EBER-positive tumors were also associated with p53 (P = 0.002), Bcl-2 (P = 0.04), and nuclear survivin (P = 0.03) expression. Patients with EBER-positive NPC fared better, with a 10-year overall survival of 68% versus 48% for EBER-negative patients (P = 0.03). For nuclear survivin, patients with either low or high nuclear survivin fared worse than patients with intermediate survivin expression (P = 0.05), suggesting that there is an optimal proportion of survivin-expressing cells for best function and clinical outcome. CONCLUSIONS: With an extended median follow-up time of 11.4 years, EBV status remains a strong predictor for overall survival in NPC. EBV-positive NPC has strong molecular associations with p53, Bcl-2, and survivin expression. Furthermore, we provide clinical data revealing the potentially dual nature of survivin in predicting clinical outcome.

Carcinoma, Squamous Cell↗

Autoimmunity to GABAA-receptor-associated protein in stiff-person syndrome.

Stiff-person syndrome (SPS) is an autoimmune neurological disorder characterized by autoantibodies to glutamic acid decarboxylase (GAD), the enzyme responsible for the synthesis of inhibitory neurotransmitter GABA. To search for biomarkers that distinguish SPS from other neurological disorders (OND), we used surface enhanced laser desorption/ionization-time of flight (SELDI-TOF) mass spectrometry to obtain proteomic profile of sera from 25 GAD-positive SPS patients and 25 controls. A significant decrease was found in the level of a protein corresponding to GABA(A)-receptor-associated protein (GABARAP), which is responsible for the stability and surface expression of the GABA(A)-receptor. Up to 70% of the SPS sera examined, compared with 10% of the controls, immunoprecipitated GABARAP protein. Antibodies raised against GABARAP immunostained neuronal cell bodies as well as axonal and dendritic processes, as visualized by confocal microscopy. In vitro experiments demonstrated that the IgG from GABARAP antibody-positive patients, but not control IgG, significantly inhibited the surface expression of GABA(A)-receptor. We conclude that GABARAP is a new autoantigen in SPS. Because the patients' IgG inhibits the expression of GABA(A)-receptors, the circulating antibodies could impair GABAergic pathways and play a role in the clinical symptomatology of SPS patients.

Adaptor Proteins, Signal Transducing↗

BMP4 activation and secretion are negatively regulated by an intracellular gremlin-BMP4 interaction.

Bone morphogenetic protein 4 (BMP4) is a potent growth factor that is involved in many important biological processes. Regulation of the level of secreted mature BMP4 determines the biological effects of BMP4 on cells in the local microenvironment. Previous studies suggested that Gremlin, a member of DAN family proteins, antagonizes BMP4 activity by sequestering extracellular BMP4. Herein, we report a novel intracellular regulatory mechanism by which Gremlin interacts with BMP4 precursor, prevents secretion of mature BMP4, and therefore inhibits BMP4 activity more efficiently. Furthermore, we also defined a 30-amino acid peptide sequence within the Gremlin DAN domain that is essential for BMP4 interaction. This novel Gremlin-mediated BMP4 posttranslational regulatory mechanism implies that the level of BMP4 mRNA expression does not truly reflect BMP4 activity when Gremlin and BMP4 are coexpressed within the same cell. Similar regulatory mechanisms may be utilized by other DAN family proteins.

Amino Acid Sequence↗

Highly efficient photoactivation of Mn-depleted photosystem II by imidazole-liganded manganese complexes.

The oxygen-evolving complex (OEC) of Mn-depleted photosystem II (PSII) can be reconstituted in the presence of exogenous Mn or a Mn complex under weak illumination, a process called photoactivation. Synthetic Mn complexes could provide a powerful system to analyze the assembly of the OEC. In this work, four mononuclear Mn complexes, [(terpy)2Mn(II)(OOCH3)] x 2 H2O (where terpy is 2,2':6',2''-terpyridine), Mn(II)(bzimpy)2, Mn(II)(bp)2(CH3CH2OH)2 [where bzimpy is 2,6-bis(2-benzimidazol-2-yl)pyridine] and [Mn(III)(HL)(L)(py)(CH3OH)]CH3OH (where py is pyridine) were used in photoactivation experiments. Measurements of the photoreduction of 2,6-dichorophenolindophenol and oxygen evolution demonstrate that photoactivation is more efficient when Mn complexes are used instead of MnCl2 in reconstructed PSII preparations. The most efficient recoveries of oxygen evolution and electron transport activities are obtained from a complex, [Mn(III)(HL)(L)(py)(CH3OH)]CH3OH, that contains both imidazole and phenol groups. Its recovery of the rate of oxygen evolution is as high as 79% even in the absence of the 33-kDa peptide. The imidazole ligands of the Mn complex probably accelerate P680*+ reduction and consequently facilitate the process of photoactivation. Also, the strong intermolecular hydrogen bond probably facilitates interaction with the Mn-depleted PSII via reorganization of the hydrogen-bonding network, and therefore promotes the recovery of oxygen evolution and electron transport activities.

Electron Transport↗

Construction of 3d-4f mixed-metal complexes based on a binuclear oxovanadium unit: synthesis, crystal structure, EPR, and magnetic properties.

The oxovanadium(IV)-lanthanide(III) heteronuclear complexes, [[Ce(H2O)7(VO)(TTHA)0.5][(VO)2(TTHA)]].8H2O (2), [Pr(H2O)7(VO)3(TTHA)1.5].10H2O (3), and [Nd(H2O)7(VO)3(TTHA)(1.5)].10H2O (4) (H6TTHA = triethylenetetraaminehexaacetic acid), were prepared based on a binuclear building block of [(VO)2(TTHA)]2- in [VO(H2O)5][(VO)2TTHA].4H2O (1). The X-ray crystallographic studies show that 1 is an ion-pair complex, containing the [(VO)2(TTHA)]2- unit as a useful building block. Adding the light Ln3+ ions to this synthesis system, three new 3d-4f mixed-metal-based complexes were obtained. Although the light lanthanide ions always exhibit similar chemical behavior, the structures of 2-4 are not homologous. 2 is exhibited as a one-dimensional coordination polymer, comprising an unusual Ce2V2 heterometallic lattice in the chain structure, which is the second report of a oxovanadium(IV)-lanthanide(III) coordination polymer. 3 and 4 are isomorphic, every two of the Ln3+ cations linked three [(VO)2(TTHA)]2- anions, forming an interesting linear octanuclear structure. This kind of heteronuclear linear complex is rather rare, which expands the realm of 3d-4f complexes. Further investigations such as IR spectra, UV-vis spectra, magnetic properties, and EPR spectra were studied, and a detailed discussion is given for this system.

Crystallography, X-Ray↗

Variation analysis of affinity-membrane model based on Freundlich adsorption.

The variation analysis of membrane properties including membrane thickness and pore-size was carried out theoretically by using affinity-membrane model based upon the Freundlich adsorption equation. As the percentage variation of membrane thickness and distribution of pore-size increase, we find that (1) the time of total saturation is delayed; (2) the loading capacity at the point of breakthrough are decreased; (3) solute recovery efficiency and ligand utilization efficiency is decreased; (4) the thickness of unused membrane is increased. The results show that even small variations of thickness and distribution of pore size may severely degrade the membrane performance.

Adsorption↗

[Choice of the surgical approach to petroclival tumor].

OBJECTIVE: To discuss the reasonable choice of the surgical approach to petroclvial tumors. METHODS: The clinical data of consecutive 53 patients with the petroclival tumors, treated from June 2002 to June 2004, were reviewed to compare the different surgical approaches to pertroclival region. RESULT: Subtemporal transtentorial approach were used in 11 patients, suboccipital retrosigmoid approach in 12 patients, (transzygomatic or orbitozygomatic) frontotemporal (pterional) approach in 12 patients, presigmoid sinus approach in 2 patients, subtemporal and retrosigmoid sinus combined approach in 7 patients, subtemporal anterior petrosal extradural approach in 7 patients and extended transfrontal base extradural approach in 2 patients. Of all patients in this group, total tumor removal was achieved in 32 patients, subtotal in 9, largely partial in 12. The new cranial nerve deficit took place in 16 patients postoperatively, two patients died from coma and serious pneumonia. CONCLUSIONS: Using perfect microsurgical technique, conventional surgical approaches on petroclival region such as suboccipital retrosigmoid approach, subtemporal transtentorial approach can be suitable for most petroclival tumor with the help of neuro-navigation and neuro-endoscopy. To the epidural tumor on petroclival region, the epidural approach should be used with less invasion to the brain tissue. And to the giant petroclival tumor, the combined-tentorial approach can provide an excellent access and exposure to the tumor.

Adolescent↗

Theoretical study of one-, two-, and three-photon absorption properties for a series of Y-shaped molecules.

In this paper, the equilibrium geometries, one-, two-, and three-photon absorption properties, and the transition nature of a series of Y-shaped molecules which possess an imidazole-thiazole core have been theoretically studied by using the parametrization model 3 and Zerner's intermediate neglect of differential overlap methods. Our calculated results have confirmed the experimental findings that the investigated molecules are all promising multiphoton absorption materials and both the two-photon absorption and the three-photon absorption cross sections are seriatim increscent along with the increase of the electron-donor strength. The nonlinear optical phenomenon originates from the intramolecular charge transfer within the pi-conjugated system. The calculated results indicate that the heterocyclic core increases the two- and three-photon absorption cross sections due to its pi-excessive nature. So it can provide more free electrons to enlarge the charge transfer within the molecule system. In addition, the design of Y shape and the sulfonyl-based electron-accepting group play a part in the enhancement of multiphoton absorption. It is notable that molecules with heterocyclic core will provide favorable condition for multiphoton absorption applications.

Journal Article↗

Laminin, VEGF, and bone matrix protein expression in uroepithelial bone induction--a canine model.

A biological and embryological bone induction from epithelial-mesenchymal cell interactions has been noticed in some developing tissues. However, the mechanism for bone formation induced by the epithelial-mesenchymal cell interactions is not clear. The aim of our study was to reveal the role of laminin, vascular endothelial growth factor (VEGF), and bone matrix proteins in mesenchymal cell differentiation during uroepithelial bone induction using a well-established canine model. In this model, a myoperitoneal muscle flap from the abdominal rectus sheath was transplanted into the bladder wall. After 6 weeks, the bladder samples were removed and assessed by histology and immunohistochemistry. This study demonstrated that bone formation occurred in two different directions with two distinct mechanisms. We noted that bone-forming cells in two types of bone formation derived from mesenchymal stem cell differentiation induced either from uroepithelium or bone autoinduction. Laminin was only expressed in peripheral regions of uroepithelium bone formation. Type II collagen was expressed both intracellularly and extracellularly around hypertrophic chondrocytes, whereas VEGF was mostly expressed in proliferating chondrocytes. This study indicates that components in basement membrane like laminin play a role in transitional epithelium-induced differentiation of mesenchymal cells to chondrocytes in muscle tissue. The sequential expression of bone matrix proteins by differentiated osteogenetic cells indicates a subsequent sequence of bone autoinduction.

Animals↗