[Molecular epidemiological characterization of hypervirulent carbapenem-resistant Klebsiella pneumoniae in a hospital in Henan Province from 2020 to 2022]

Objective: The study investigated the clinical distribution, antimicrobial resistance and epidemiologic characteristics of hypervirulent Carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) in a hospital in Henan Province to provide a scientific basis for antibiotic use and nosocomial infection prevention and control. Methods: A retrospective analysis of the clinical data from the cases was carried out in this study. Clinical data of patients infected with the CRKP strain isolated from the clinical microbiology laboratory of Henan Provincial Hospital of Traditional Chinese Medicine from January 2020 to December 2022 were retrospectively analyzed. A string test, virulence gene screening, serum killing, and a G. mellonella infection model were used to screen hv-CRKP isolates. The clinical characteristics of hv-CRKP and the drug resistance rate of hv-CRKP to twenty-five antibiotics were analyzed using WHONET 5.6. Carbapenemase phenotypic characterization of the hv-CRKP was performed by colloidal gold immunochromatographic assay, and Carbapenemase genotyping, multi-locus sequence typing (MLST) and capsular serotyping of hv-CRKP isolates were performed by PCR and Sanger sequencing. Results: A total of non-duplicate 264 CRKP clinical isolates were detected in the hospital from 2020 to 2022, and 23 hv-CRKP isolates were detected, so the corresponding detection rate of hv-CRKP was 8.71% (23/264). The hv-CRKP isolates in this study were mainly from the intensive care unit (10/23) and neurosurgery department (8/23), and the main sources of hv-CRKP isolates were sputum (10/23) and bronchoalveolar lavage fluid (6/23). The hv-CRKP isolates in this study were highly resistant to β-lactam antibiotics, fluoroquinolones and aminoglycosides, and were only susceptible to colistin, tigecycline and ceftazidime/avibactam. The detection rate of the blaKPC-2 among 23 hv-CRKP isolates was 91.30% (21/23) and none of the class B and class D carbapenemases were detected. Results of MLST and capsular serotypes showed that ST11 type hv-CRKP was the dominant strain in the hospital, accounting for 56.52% (13/23), and K64 (9/13) and KL47 (4/13) were the major capsular serotypes. Conclusion: The hv-CRKP isolates from the hospital are mainly from lower respiratory tract specimens from patients admitted to the intensive care department and the drug resistance is relatively severe. The predominant strains with certain polymorphisms are mainly composed of the KPC-2-producing ST11-K64 and ST11-KL47 hv-CRKP isolates in the hospital.

[Constructions and advances of animal models of Pseudomonas aeruginosa infection]

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogenic bacterium with complex pathogenesis and drug resistance mechanisms. It has high morbidity and mortality and can cause acute and chronic infections in immunocompromised individuals, with lung infections, wound infections, and bloodstream infections being the most common. The animal infection model of P. aeruginosa is of great value for in-depth research on the pathogenicity, drug resistance, and therapeutic measures of P. aeruginosa by simulating the pathways of human bacterial infections. This article firstly summarizes the selection, anesthesia, and disposal of experimental animals in the construction of animal models of P. aeruginosa infection, and then reviews the methods of construction, model evaluation, and applications of animal models of P. aeruginosa pulmonary infection, wound infection, and bloodstream infection, in order to provide a reference for scientific research related to P. aeruginosa infectious diseases.

[Sensitization characteristics of Juniperus chinensis pollen in Beijing area]

Objective: To investigate the sensitization characteristics of Juniperus chinensis pollen in patients with allergic rhinitis and/or allergic asthma in Beijing area, and to explore the characteristics of Juniper chinensis pollen sensitized population. Methods: Patients with suspected allergic rhinitis and/or asthma from January 2017 to December 2019 in the outpatient department of Allergy Department of Beijing Shijitan Hospital were selected in this study. Skin prick test (SPT) was performed with Juniper chinensis pollen allergen reagent to compare different age and disease allergen distribution, and to observe the sensitization characteristics of its population. All of the analyses were performed using SAS software version 9.4. Results: A total of 8 380 patients were enrolled in the end. The total positive rate of Juniper chinensis pollen SPT reached 49.92% (4 183/8 380). The positive rate of Juniper chinensis pollen SPT was highest in the 10-14 age group, reaching 60.99% (283/464). Compared with other age groups, there was a statistical difference (χ²=266.77, P<0.01). The SPT positive rate of patients aged less than 10 years increased with the increase of age, while the SPT positive rate of patients aged over 40 years decreased with the increase of age. Single Juniper chinensis pollen was less allergenic, accounting for about 25.05% (1 048/4 183), and the patients' age was (35.21±12.39) years. Regardless of single Juniper chinensis pollen or other pollen allergies, allergic rhinitis was the main disease. Among the patients with SPT positive Juniper chinensis pollen combined with other inhaled pollen allergens, willow pollen accounted for the first (74.99%). The positive rate of Juniper chinensis pollen was the highest in patients with single allergic rhinitis, accounting for 52.05% (3 797/7 295), and the rate in patients with single allergic asthma was the lowest, accounting for 17.49% (53/303), with statistically difference (χ²=138.99, P<0.01). Conclusions: Juniper chinensis pollen is highly sensitized in patients with allergic rhinitis and/or allergic asthma in Beijing . The positive rate of SPT is highest among 10-14 age group, most of which showed strong positive reaction, and allergic rhinitis is more common in Juniper chinensis pollen sensitization diseases.

[Research progress on virulence factors of hypervirulent Klebsiella pneumoniae]

Hypervirulent Klebsiella pneumoniae, short for hvKP, is a hypervirulent variant of classical Klebsiella pneumoniae, which accounts for serious infection in healthy people, exhibits strong pathogenicity, high mortality and poor prognosis. At present, hvkp is of high prevalence all over the world, and the infection rate shows a continuous upward trend, which brings great challenges to public health security and clinical treatment. This paper summarized the research progress on virulence factors of hvkp, such as capsular polysaccharides, siderophore, lipopolysaccharide, adhesins and recently discovered Type Ⅵ secreting system, and aimed to deepen the understanding and recognition of hvKP.

[Reoperation rate and related factors in patients with Crohn's disease]

Objective: To analyze the cumulative reoperation rate of postoperative Crohn's disease (CD) patients and investigate the operation reasons and the effects of drugs on surgical recurrence. Method: Patients with Crohn's disease who had undergone intestinal resection from January 2000 to March 2020 in Peking Union Medical College Hospital were enrolled. Patients were divided into reoperation and non-reoperation group according to whether they had a second operation. And the basic characteristics and the reasons for the primary and second operation were retrospectively analyzed. Meanwhile, patients were divided into low-risk reoperation group and high-risk group based on risk stratification. Kaplan-Meier methods were performed to analyze the cumulative surgical recurrence rate and to compare the recurrence rate in different risk stratification and chi-square tests was used to analyze the effects of different maintenance drugs on reoperation. Result: A total of 160 patients were enrolled in the study. There were 110 males and 50 females, and the age at first operation was (35.6±14.1) years old. There were 40 patients in the reoperation group and 120 patients in the non-reoperation group. According to univariate analysis, the proportion of male gender(P=0.030), penetrating phenotype(P<0.001), history of appendectomy before the primary surgery(P=0.035) and no postoperative maintenance therapy (P<0.001) were higher in surgical recurrence group. In terms of the operation reasons, intestinal obstruction accounted for the highest proportion in the primary operation (26.9%, 43/160), while the intestinal fistula was the most common reason for reoperation (42.5%, 17/40). After the primary surgery, the cumulative reoperation rates at 1, 3, 5 and 10 years were 5.9% (9 cases), 12.3% (17 cases), 21.8% (25 cases) and 37.6% (34 cases), respectively. The ten years cumulative reoperation rate of the high-risk group was 42.8% (31 cases), which was much higher than that of low-risk group (19.8%, 3 cases), and the difference was statistically significant (P=0.006). There was no statistically significant difference in the surgical recurrence rate of low-risk group patients(P=0.076)whether maintenance therapies were added or not, while the recurrence rate of high-risk group patients who did not receive maintenance therapy was higher than those who received immunosuppressant with or without (±) 5-aminosalicylic acid (ASA) (P=0.001) and biological agent±5-ASA (P=0.001), and the difference was statistically significant. Conclusion: Patients with CD are still at risk of reoperation after surgery. Immunosuppressive agents and biologics can prevent patients from reoperation in high-risk groups.

[Research progress on the regulation mechanism of Pseudomonas aeruginosa biofilm]

Pseudomonas aeruginosa is one of the common multidrug-resistant bacteria in the clinic. Because it can produce a "protective" biofilm, it can affect the penetration and killing efficacy of antibacterial drugs, leading to the formation of a persistent and persistent chronic infection in the host. Biofilms make Pseudomonas aeruginosa resistant to antibacterials and evasive to the host's immune system. Therefore, traditional conventional antibacterials are difficult to achieve effective bactericidal treatment. Understanding the process of P. aeruginosa biofilm formation and the regulatory mechanisms that affect biofilms can provide ideas and methods for our future research on new antibacterial drugs.

[Analysis on clinical features of patients with ulcerative colitis associated colorectal cancer]

Objective: To analyze the clinical features of ulcerative colitis associated colorectal cancer (UC-CRC). Methods: A total of 869 inpatients with Ulcerative Colitis (UC) in Peking Union Medical Hospital from January 1998 to January 2018 were continuously enrolled. Clinical data and the outcome of colorectal cancer (CRC) were collected via medical records and telephone follow-up. Chi-square test and logistic regression model were used to analyze the data. Results: There were 16 patients in 869 UC inpatients who were diagnosed with CRC during a period of 7 548 person years and the incidence rate of UC-CRC was 1.84%. Compared to UC inpatients without CRC, a longer course of disease (OR=1.087, 95% CI:1.046-1.129) , a lower usage rate of 5-Aminosalicylic Acid(5-ASA) (OR=0.218, 95% CI:0.052-0.915) and a higher incidence rate of intestinal stenosis (OR=16.533, 95% CI:3.824-71.478) were found in UC inpatients with CRC. Conclusions: A long disease course is a risk factor for UC patients developing CRC, while 5-ASA therapy can reduce the risk of suffering from CRC. For UC patients with intestinal stenosis, CRC should be warned for occurring.

Characterization of microbial community profiles associated with quality of Chinese strong-aromatic liquor through metagenomics

AIMS

Microorganisms in fermentation pits (FPs) play key roles for Chinese-strong-aromatic-liquor (CSAL) production. However, the microbial community in the FPs is still poorly understood. Here, the aim of this study was to reveal the diversity and potential functions of microbiota in FPs.

METHODS AND RESULTS

Sequencing-by-synthesis-based metagenomic sequencing and annotation results revealed that the microbiota of FPs was primarily composed of Firmicutes (54·6%), Euryarchaeota (15·3%), Bacteroidetes (10·1%), Gammaproteobacteria (5·8%), Opisthokonta (5·7%) and Unclassified_Bacteria (2·3%). And 133 genera were identified as the dominant genera of this fermentative food. Lactobacillus, Sedimentibacter, Syntrophomonas, Methanoculleus, Methanobacterium, Bacillus, Clostridium, Galactomyces, Candida, Pichia, Penicillium and Aspergillus were defined as active populations for biosynthesizing the characteristic volatile compounds of CSAL. The study also revealed that the microbial community structures changed significantly with different cellar ages and over different geographical regions. (i) The presence of Bacteroidetes was the most distinctive feature that characterized the different FPs ages. (ii) Distinct contents of Gammaproteobacteria and Euryarchaeota were observed at different positions in the FPs. (iii) Euryarchaeota markedly contributed to the generation of the character of the liquors with distinct geographical associations.

CONCLUSIONS

This study demonstrated that the changes of microbial communities determined the different quality characteristics of CSAL.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research contributes to a deeper understanding of the FPs microbial composition and shows a new microbial resource for biotechnological applications.

[Immunometabolism and systemic lupus erythematosus]

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease, characterized by production of pathogenic autoantibodies and wide involvement of multiple systems. Damageofimmune tolerance and imbalance of immune homeostasis lead to the production of autoantibodies and the injuries of multiple organs and systems. In recent years, plenty of studies have identified that immunometabolism affects survival status of certain cells, also cell activation, differentiation and effector functions. Conversely, immune cells with different functions or differentiational status upregulate specific metabolic pathways to maintain their identities. In response to outer stimulations, naive immune cells differentiate into activated cells, accompanied with a series of immunometabolism changes. Therefore, abnormal immunometabolism can induce global imbalance of immune homeostasis, which further results in the initiation and development of autoimmune diseases, including SLE. Multiple abnormalities of immunometabolism have been found in patients with SLE or mouse models of lupus. Immune cells involved in the development of SLE, such as T cells, B cells, dendritic cells and macrophages present various metabolic abnormalities and pathological phenotypes. Among these cells, CD4+ T cells play predominant roles in the pathogenesis of SLE. Lots of studies demonstrated that CD4+ T cells and their subsets were in abnormal immunometabolic status,which further resulted in the development of SLE. In CD4+ T cells from patients with SLE or mouse models of lupus, both levels of glycolysis and oxidative phosphorylation are significantly higher compared with healthy controls. However,mitochondrial abnormalities, decreased ATP production and increased level of oxidative stress also have been found in these cells, which play important roles in the production of reactive oxygen intermediates and autoantibodies. Aggregated lipids rafts and increased synthesis of glycosphingolipid and cholesterol also have been observed in the CD4+ T cells from patients with SLE, leading to the abnormally elevated TCR signaling. Moreover, mechanistic target of rapamycin (mTOR) signaling is activated in the CD4+ T cells from both patients with SLE or mouse models of lupus and participate in the metabolic abnormalities of pathological CD4+ T cells. Progressive understanding of immunometabolism give us new insights of the pathogenesis of SLE and provide us with more therapeutic targets in the treatment of SLE.

Mathematical modeling of atherosclerotic plaque destabilization: Role of neovascularization and intraplaque hemorrhage

Observational studies have identified angiogenesis from the adventitial vasa vasorum and intraplaque hemorrhage (IPH) as critical factors in atherosclerotic plaque progression and destabilization. Here we propose a mathematical model incorporating intraplaque neovascularization and hemodynamic calculation with plaque destabilization for the quantitative evaluation of the role of neoangiogenesis and IPH in the vulnerable atherosclerotic plaque formation. An angiogenic microvasculature is generated by two-dimensional nine-point discretization of endothelial cell proliferation and migration from the vasa vasorum. Three key cells (endothelial cells, smooth muscle cells and macrophages) and three key chemicals (vascular endothelial growth factors, extracellular matrix and matrix metalloproteinase) are involved in the plaque progression model, and described by the reaction-diffusion partial differential equations. The hemodynamic calculation of the microcirculation on the generated microvessel network is carried out by coupling the intravascular, interstitial and transvascular flow. The plasma concentration in the interstitial domain is defined as the description of IPH area according to the diffusion and convection with the interstitial fluid flow, as well as the extravascular movement across the leaky vessel wall. The simulation results demonstrate a series of pathophysiological phenomena during the vulnerable progression of an atherosclerotic plaque, including the expanding necrotic core, the exacerbated inflammation, the high microvessel density (MVD) region at the shoulder areas, the transvascular flow through the capillary wall and the IPH. The important role of IPH in the plaque destabilization is evidenced by simulations with varied model parameters. It is found that the IPH can significantly speed up the plaque vulnerability by increasing necrotic core and thinning fibrous cap. In addition, the decreased MVD and vessel permeability may slow down the process of plaque destabilization by reducing the IPH dramatically. We envision that the present model and its future advances can serve as a valuable theoretical platform for studying the dynamic changes in the microenvironment during the plaque destabilization.

Transcriptome analysis of potential simple sequence repeat markers in Ammopiptanthus mongolicus

Ammopiptanthus mongolicus, an evergreen broadleaf legume shrub, can survive under conditions of high and low temperature, extreme salinity, and drought. This attribute makes it an ideal model for studying mechanisms of stress tolerance in plants. However, simple sequence repeat (SSR) resources for this species are insufficient in public databases. In this study, a total of 44,959 unigenes identified from the A. mongolicus transcriptome were used for SSR analysis by MIcroSAtellite (MISA). A total of 13,859 SSRs were found to be distributed within 10,409 unigenes, with an average length of 15 bp and an average density of one SSR per 4.4 kb. There were 222 different motif types in the A. mongolicus transcriptome, and mononucleotide repeats represented the main type, accounting for 44.2% of all SSRs. The (A/T)n repeat was the most frequent motif, accounting for 42.37% of all SSRs. We also performed Gene Ontology functional analysis, Kyoto Encyclopedia of Genes and Genomes database pathway analysis, and eggNOG analysis, and identified 6157, 2301, and 9845 unigenes containing SSRs in these three databases, respectively. The functional categorization of A. mongolicus unigenes containing SSRs revealed that these unigenes represent many transcribed genes with different functions. These data provide sequence information that may be used to improve molecular-assisted markers for the study A. mongolicus genetic diversity.

A novel role of angiopoietin-like-3 associated with podocyte injury

BACKGROUND

Angiopoietin-like-3 (ANGPTL3) expression is increased in glomerular podocytes of nephrotic syndrome. We hypothesize whether ANGPTL3 plays an important role in podocyte injury and promoting proteinuria.

METHODS

Angptl3(+/+) and Angptl3(-/-) female mice on B6;129S5 gene background were injected with adriamycin by tail vein at the dose of 25 mg/Kg to produce nephropathy. Proteinuira was measured and podocytes ultrastructure was observed by electron microscopy. The interaction between ANGPTL3 and intergrin β3 was analyzed by CO-IP and confocal immunofluorescence. The relative gene and protein expression were analyzed by RT-PCR and western blot.

RESULTS

The deletion of ANGPTL3 tremendously attenuates proteinuria (more than a fivefold decrease in albuminuria) and protects podocytes from injury in a mouse model of adriamycin-induced nephropathy. We further demonstrate that ANGPTL3 interacts with and activates podocyte-expressed integrin β3 and regulate expression of α-actinin-4, which may result in the cytoskeletal rearrangement of podocytes. Additionally, we identify the activation of the ANGPTL3-integrin β3 signaling pathway in patients with nephrotic syndrome.

CONCLUSION

ANGPTL3 might play a crucial role in podocyte injury. Either decreasing ANGPTL3 expression or interfering with the ANGPTL3-integrin β3 interaction might be benefit for podocyte protection and decrease proteinuira.

Antibacterial activity of ZnO nanoparticles with a modified surface under ambient illumination

In various practical applications, nanomaterials typically have functionalized surfaces. Yet, the studies of toxicity and antibacterial activity of functionalized nanoparticles are scarce. We investigated the effect of surface modifications on antibacterial activity of ZnO under ambient illumination, and we found that nanoparticles coated with different surface modifying reagents could exhibit higher or lower toxicity compared to bare ZnO, depending on the surface modifying reagent used. Different surface modifying reagent molecules resulted in differences in the release of Zn(2+) ions and the production of reactive oxygen species (ROS). However, the antibacterial activity did not correlate with the ROS levels or the Zn(2+) ion release. One of the surface-modified ZnO samples exhibited significantly lower Zn(2+) ion release while at the same time exhibiting improved antibacterial activity. In all cases, damage of the cell wall membranes and/or changes in the membrane permeability have been observed, together with the changes in ATR-FTIR spectra indicating differences in protein conformation. Mechanisms of antibacterial activity are discussed.

[Expression of neonatal Fc receptor on human nephritis and rat nephritis models]

OBJECTIVE

To study the expression of neonatal Fc receptor in podocytes in human nephritis and immune-induced rat nephritis models: anti-Thy1.1 nephritis and Heymann nephritis.

METHODS

Thirty-nine cases of renal biopsies were enrolled from September 2009 to February 2010, including 8 cases of minimal change disease, 4 cases of focal segmental glomerulosclerosis, 9 cases of membranous nephropathy, 12 cases of IgA nephropathy and 6 cases of lupus nephritis. Five normal kidney tissue samples adjacent to renal clear-cell carcinoma were served as normal controls. Laser capture microdissection and real-time RT-PCR were used to assess the expression level of FcRn mRNA in glomeruli of various glomerulonephritides, and immunohistochemistry (IHC) of FcRn by SuperVision method was performed. In addition, rat models of mesangial proliferative nephritis (anti-Thy1.1 nephritis) and passive membranous nephropathy (Heymann nephritis) were established and FcRn was examined in renal tissues by IHC.

RESULTS

The FcRn mRNA level in lupus nephritis was statistically higher than that of normal controls (P < 0.05). FcRn protein expression by IHC was seen in lupus nephritis (6/6), membranous nephropathy (6/9) and IgA nephropathy (7/12), significantly higher than that of normal controls (0/5), P < 0.05. Minimal change disease and focal segmental glomerular sclerosis showed minimal or none expression of FcRn (1/8, 0/4 respectively) and not statistically difference from that of normal controls. Furthermore, FcRn expression in podocytes was detected in rat anti-Thy1.1 (3/5) and Heymann nephritis models (2/7) but was not detected in normal controls.

CONCLUSIONS

Expression of FcRn in podocytes was up-regulated in immune-induced human nephritis and rat nephritis models of anti-Thy1.1 nephritis and Heymann nephritis. FcRn may play a role in the development of immune-induced glomerulonephritis.

[FAK/c-Src signaling pathway mediates the expression of cell surface HSP90 in cultured human prostate cancer cells and its association with their invasive capability]

OBJECTIVE

To investigate the expression of heat shock protein 90 (HSP90) on the cell surface of highly invasive human prostate cancer cells PC3 and its possible molecular mechanisms of its effect on cell invasion through analyzing FAK/Src signaling pathway.

METHODS

The expression of cell surface HSP90 on PC3 cells was studied by immunofluorescence staining and surface biotinylation assay respectively. A specific HSP90 antibody was used to inhibit the cell surface HSP90. In vitro cell invasion was assessed by modified Boyden chambers. Phosphorylated FAK on tyr 397, 576, 577 and 925, and phosphorylated c-Src on tyr 416 were examined by Western blot assay. The association between FAK and c-Src was analyzed by immunoprecipitation. The effects of FAK knockdown by siRNA or Src kinases inhibitor PP2, with or without anti-HSP90 antibody, on PC3 cell invasion were also evaluated.

RESULTS

A pool of HSP90 was detected on the cell surface of PC3 cells. A specific HSP90 antibody significantly retarded tumor cell invasion. Concomitant with this finding, targeting cell surface HSP90 significantly inhibited the phosphorylations of FAK and c-Src, and also the interactions between FAK and c-Src. FAK knockdown or PP2 dramatically suppressed cell invasion, however, anti-HSP90 antibody didn't further inhibit cell invasion.

CONCLUSIONS

Cell surface HSP90 promotes human prostate cancer cell invasion through a FAK/c-Src signaling, with may be a novel therapeutic target against metastatic tumors.

Cell surface heat shock protein 90 modulates prostate cancer cell adhesion and invasion through the integrin-β1/focal adhesion kinase/c-Src signaling pathway

Heat shock protein (Hsp) 90 is a molecular chaperone that maintains the active conformation and function of numerous client oncoproteins in cancer cells. Hsp90 has also been detected on the plasma membrane of cells, and its expression has been suggested to correlate with metastatic potential. We studied the PC3 cell line, which is a highly invasive human prostate cancer cell line, and confirmed that Hsp90 is present on the cell surface of PC3 cells. Interestingly, cell surface Hsp90 was also specifically localized at the leading edge of migrating cells. By using a specific antibody that inhibited cell surface Hsp90, adhesion and invasion of PC3 cells were significantly suppressed in vitro. Concomitantly with these findings, we demonstrated that the inhibition of cell surface Hsp90 not only inhibited the FN-dependent association between FAK, c-Src and integrin β1, but also significantly inhibited the phosphorylation of FAK and c-Src, as well as their downstream targets paxillin and p130Cas. Additionally, the Hsp90 antibody reversed cell invasion stimulated by overexpression of FAK. These data indicate that cell surface Hsp90 is involved in prostate cancer cell invasion through the integrin β1/FAK/c-Src signaling pathway. Our study provides new insights into the mechanisms of cell surface Hsp90 in cancer invasion. These results suggest that molecular targeting of cell surface Hsp90 may therefore be a novel target for the effective treatment of metastatic prostate cancer.

Regulation of intracellular decorin via proteasome degradation in rat mesangial cells

Decorin (DCN) is a member of small leucine-rich proteoglycan family that neutralizes the bioactivity of transforming growth factor-beta1 (TGF-β1). It has been proven to be a promising anti-fibrotic agent to treat glomerulonephritis. But the underlining mechanism for regulating and degrading intracellular DCN is still not fully understood. In this study, we investigated the roles of ubiquitination in the regulation of cytoplasmic DCN metabolism in rat mesangial cells (MC) by immunoprecipitation and Western blot. The results showed that a proportion of cytoplasmic DCN was ubiquitinated in normal MC and was enhanced in N-glycosylation inhibitor (tunicamycin)-treated MC. After being treated with the proteasome inhibitor MG132, ubiquitinated DCN accumulated and displayed a prolonged half-life, accompanied by decreased TGF-β1 expression and reduced collagen IV mRNA level in MC. This study demonstrated that the stability and function of cytoplasmic DCN can be regulated by ubiquitin-proteasome system (UPS) in MC, which implies that regulating the ubiquitination and degradation of DCN might be a novel approach for modulating MC bioactivity.

Role of cross-talk between the Smad2 and MAPK pathways in TGF-beta1-induced collagen IV expression in mesangial cells

Transforming growth factor beta1 (TGF-beta1) can promote sclerosis in many kidney diseases by enhancing the synthesis of collagens. However, the mechanisms of down-stream intracellular signal transduction in TGF-beta1-induced collagen synthesis is not fully understood. The purpose of this study was to further investigate the mechanisms and the cross-talk between the MAPK and Smad2 pathways. We found that U0126, a specific inhibitor of ERK1/2, and SB203580, a specific inhibitor of p38, down-regulated the TGF-beta1-induced phosphorylation of Smad2 at both linker and C-terminal sites in rat mesangial cells. Whereas, SP600125, a specific inhibitor of JNK, only down-regulated the phosphorylation of Smad2 at the C-terminal sites, but had little effect on the phosphorylation of Smad2 at linker sites. However, all three MAPK inhibitors reduced collagen IV synthesis induced by TGF-beta1. Furthermore, TGF-beta1 induced the phosphorylation of Smad2 at both the linker and C-terminal sites. Transient transfection of a dominant negative Smad2 construct significantly decreased TGF-beta1-induced phosphorylation of ERK1/2, JNK and expression of collagen IV, but did not decrease the phosphorylation of p38. These findings demonstrate that there is cross-talk between the MAPK (ERK1/2, JNK, p38) and Smad2 pathways, and that the cross-talk interacts mutually to enhance the synthesis of collagen IV in rat mesangial cells.

[Electron microscopic examination on 50 cases of prostatic needle biopsies]

OBJECTIVE

To study the differences in ultrastructural findings between prostatic carcinoma and benign prostatic hypertrophy, and the various ultrastructural features seen in moderately to poorly differentiated prostatic carcinoma.

METHODS

Utrasound-guided needle biopsies were carried out in 50 clinically suspicious cases of prostatic carcinoma. For each case, one additional core was sampled from the most suspicious area, fixed in glutaraldehyde and examined under electron microscopy.

RESULTS

In the 50 cases of prostatic needle biopsies studied, there were a total of 42 cases with histologic findings of prostatic carcinoma. Thirty-one cases showed features corresponding to Gleason's score 3 to 5. In contrast to that seen in benign prostatic hypertrophy, the ultrastructural findings of the tumor cells commonly seen in prostatic carcinoma included the centrally located giant nucleoli, a direct contact with stroma, and formation of cytoplasmic microcyst. Occasionaly, there were mitotic figures seen, accompanying with fibromyxoid change of the peritumoural stroma. Amongst the 31 cases of Gleason's score 3 to 5 prostatic carcinoma, 29 cases (93.5%) demonstrated cytoplasmic prostasomes and storage vesicles. Similar to their counterparts in benign prostatic cells, prostasomes and storage vesicles in prostatic carcinoma cells were formed in the Golgi apparatus and released into the lumen by apocrine excretion and exocytosis.

CONCLUSIONS

Electron microscopy is helpful in distinguishing between benign and malignant prostatic lesions. Because of the high yield of prostasomes in moderately to poorly differentiated prostatic carcinoma, prostasomes may become a potential target for cancer immunotherapy and one of the useful diagnostic indices for delineating the prostatic origin of metastatic carcinoma.

Expression of USP2-69 in mesangial cells in vivo and in vitro

Ubiquitin-specific protease 2 (USP2) is a member of a family of de-ubiquitinating enzymes. It may play an important role in the regulation of cell growth and differentiation. It is known that expression of the isoform USP2-69 kD is high in kidney tissue, but its role remains unclear. Mesangial cell proliferation is a prominent element of various types of glomerulonephritides. Therefore, whether USP2 plays a role in mesangial cell proliferation during glomerulonephritides is an interesting question to explore. The purpose of the present study was to evaluate USP2-69 expression in needle biopsies of human kidneys and in cultured rat mesangial cells. On immunohistochemistry USP2-69 was upregulated in some mesangial proliferative glomerulonephritides. The proportion of USP2-69 positive area in the glomeruli was 3.90% in normal kidney, 4.96% in minimal change disease, and 4.39% in membranous glomerulonephritides, while it was 14.84% in IgA nephropathy (IgAN) (mesangial proliferative type), 16.18% in lupus nephritis (LN; diffuse proliferative type) and 15.54% in acute proliferative glomerulonephritides (APGN); the difference of the percentages between IgAN, LN (IV subtype) and APGN and normal kidney were statistically significant (P < 0.05). Additionally, the number of proliferating cell nuclear antigen (PCNA)-positive nuclei in the glomeruli was statistically significantly higher in the various glomerulonephritides than in the normal kidney (P < 0.05). Immunohistochemistry showed that the distribution of the USP2(+) area and PCNA(+) nuclei overlapped in the glomeruli. Treatment with interleukin-1beta for 12 h and 24 h, or with anti-thymocyte serum for 6 h and 12 h resulted in elevated USP2-69 mRNA and protein expression in the rat mesangial cells. Also, PCNA expression increased and p27 expression decreased significantly in the treated mesangial cells. These findings suggest that USP2-69 was upregulated in mesangial cells during mesangial proliferative glomerulonephritides in vivo and in vitro, which may relate to the proliferation of mesangial cells.

[Apoptosis inducing factor mediates cisplatin-induced apoptosis of renal tubular epithelial cells]

OBJECTIVE

To investigate the involvement of apoptosis inducing factor (AIF) in caspase-independent pathway mediating apoptosis of cultured renal tubular epithelial cells induced by cisplatin (CP).

METHODS

Western Blot analysis and real-time PCR were performed to detect cytosol AIF (cAIF), nuclear AIF (nAIF) and AIF mRNA expression in cultured renal epithelial cells (HK-2) treated with cisplatin (CP) at various concentrations (0 - 200 micromol/L) and time courses (0 - 12 h). Immunofluorescence analysis was used to detect the AIF protein distribution in HK-2 cells. Pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA treatment, TUNEL and flow cytometer were used to measure the suppression of apoptosis induced by CP in HK-2 cells.

RESULTS

The expressions of cAIF, nAIF protein and AIF mRNA were all increased to some extent in HK-2 cells treated with CP at various concentrations and time points. cAIF expression was 2.3-fold (P < 0.05) increased after 25 micromol/L CP treatment for 12 h and 1.7-fold (P < 0.01) increased after 50 micromol/L CP treatment for 3 h, compared with that of control groups, and showed a concentration- and time-dependent increment. The nAIF expression reached a peak (4.3-fold increase) (P < 0.005) after 150 micromol/L CP treatment for 12 h and 3.7-fold incease (P < 0.05) after 50 micromol/L CP treatment for 9 h, compared with that of the 25 micromol/L group and 3 h group, respectively. The expression of nAIF was approximately consistent with cleaved-PARP expressive pattern. Real-time PCR showed that AIF mRNA increased gradually with prolonged treatment with 50 micromol/L CP and reached a peak at 9 h. Immunofluorescence assay showed AIF translocation from cytosol to nuclei in some cultured HK-2 cells treated with CP. Applying pan-caspase inhibitor (Z-VAD-FMK) and AIF-siRNA to CP-treated HK-2 cells, the apoptotic rates were decreased by 60.1% and 39.2%, respectively. The inhibitory effect on HK-2 cell apoptosis was even more significant with combination of both Z-VAD-FMK and AIF-siRNA.

CONCLUSION

The AIF activation and translocation to nuclei with the increment of its mRNA expression mediates CP-induced apoptosis of renal tubular epithelial cells in vitro. It may provide a new therapeutic target for protecting from nephrotoxciity of cisplatin.

Overexpression of decorin induces apoptosis and cell growth arrest in cultured rat mesangial cells in vitro

BACKGROUND

Decorin (DCN) is a small leucine-rich proteoglycan that plays an important role in the regulation of intercellular contact, cell migration and proliferation. DCN suppresses cell growth and induces apoptosis in various tumour cells. The aim of this study was to investigate whether overexpression of DCN could induce apoptosis and cell growth arrest in mesangial cells (MsCs) in vitro.

METHODS

PcDNA3.1A-DCN plasmid was transfected into cultured rat MsCs, and positive clones stably expressing DCN (MsC/DCN) were selected. SiRNA was used for blocking DCN expression in MsC/DCN. Apoptosis and cell growth of MsCs were assayed by flow cytometry. Hoechst staining was used for observing apoptotic cells. Expressions of active Caspase-3, epidermal growth factor receptor (EGFR), P21 and transforming growth factor-beta (TGF-beta1) were analyzed using Western blot.

RESULTS

Overexpression of DCN in MsCs induced apoptosis and arrested cells in the G(0)/G(1) phase. The protein level of active Caspase-3 was significantly elevated in MsC/DCN (P < 0.01). DCN transfection induced downregulation of EGFR and up-expression of P21. In addition, the expression of TGF-beta1 was significantly inhibited. DCN-siRNA transfection remarkably blocked the expression of DCN and reversed the downregulatory effects of DCN on MsC's proliferation.

CONCLUSION

Overexpression of DCN could inhibit MsCs proliferation by inducing apoptosis and cell growth arrest in vitro and it also downregulates expression of TGF-beta1. These results suggest novel strategies for regulating the proliferation of MsC in glomerular diseases.

[Clinicopathologic analysis of 34 patients with microscopic polyangitis]

OBJECTIVE

To study the clinicopathologic features of microscopic polyangitis (MPA), and to compare the differences in anti-neutrophil cytoplasmic autoantibody (ANCA)-positive and ANCA-negative patients, as well as in ANCA-positive cases with or without glomerular immunoglobulin deposition.

METHODS

Thirty-four biopsy-proven cases of MPA were retrieved from the archival files of the Department during the past 7 years. The clinicopathologic characteristics between ANCA-positive and negative patients, as well as between ANCA-positive cases with and without glomerular immunoglobulin deposition, were compared.

RESULTS

Amongst the 34 MPA patients studied, about one-fifth to one-half were accompanied by various extrarenal symptoms. Serum ANCA was positive in 26 patients (76.5%). A slight to moderate increase in urinary protein was demonstrated in 31 patients, while 3 patients had nephrotic syndrome. Elevated serum creatinine was detected in 32 cases. Renal biopsy revealed crescentic glomerulonephritis in 24 cases, focal segmental glomerulonephritis in 8 cases, vascular fibrinoid necrosis with inflammation in 7 cases, intimal thickening of arterioles in 24 cases, interstitial inflammatory cells, including neutrophil infiltration (21 cases), in 29 cases. Crescentic formation was more common in the ANCA-positive group than in the ANCA-negative group (P < 0.05). Amongst the 26 ANCA-positive cases, 10 had glomerular immunoglobulin deposits (including 1 case with IgA nephropathy). In general, these cases had a greater degree of proteinuria than those without glomerular immunoglobulin deposits (P < 0.05).

CONCLUSIONS

The diagnosis of MPA relies on histologic examination of renal biopsy and clinicopathologic correlation. Serum ANCA seems important for glomerular crescent formation. Glomerular immunoglobulin deposition may also play a significant role in the exacerbation of proteinuria.

[Effect of interferon-gamma on transforming growth factor beta/Smad signal pathway and expression of matrix metalloproteinase-2 and tissue inhibitors of matrix metalloproteinase-2 in cultured rat mesangial cells]

OBJECTIVE

To study the effect of interferon-gamma (IFN-gamma) on the proliferation of mesangial cells (MsC) and transforming growth factor (TGF)-beta/Smad signal pathway, the mRNA and protein expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2), and to provide an experimental basis for IFN-gamma treatment of renal fibrosis.

METHODS

Cultured MsC were treated with IFN-gamma at different concentrations and the proliferation of MsC was examined by MTT. Protein and RNA samples were extracted from MsC at 0, 0.5, 1, 2, 4, 6, 12, 24 h after treated by 100 IU/ml IFN-gamma. The mRNA and protein expression of Smad3, Smad7, MMP-2 and TIMP-2 were analyzed by real-time RT-PCR and Western blot, respectively.

RESULTS

The expression of Smad7 mRNA and protein were promptly elevated at 0.5 hour after the IFN-gamma treatment and lasted for 6 hours, but the proliferation of MsC was not altered. The elevated expression of Smad3, MMP2 mRNA and proteins persisted after 6 hours, whereas the expression of TIMP-2 mRNA and protein decreased.

CONCLUSION

The therapeutic effect of IFN-gamma of renal fibrosis may be mediated by TGF-beta/smads signal pathway through up-regulation of MMP-2 expression, coupled with down-regulation of TIMP-2 expression.

[Changes of fibronectin and type IV collagen expression in cultured rat mesangial cells transfected with connective tissue growth factor expression vector]

OBJECTIVE

To study the role of connective tissue growth factor (CTGF) in the development of glomerulosclerosis by experimental alteration of fibronectin (FN) and Type IV collagen (Col IV) expression in cultured rat mesangial cells (MsC).

METHODS

CTGF expression vector was transfected into MsC by Lipofectimine method. Protein and mRNA expression levels of CTGF, FN and Col IV were studied by Western blot and reverse transcription-polymerase chain reaction (RT-PCR) respectively.

RESULTS

Two of MsC clones (MCT-1 and MCT-2) with CTGF overexpression were successfully established and found to have significant increases of FN and Col IV at both protein and mRNA levels. Compared with the controls, the expression of FN protein and mRNA in the two clones were 3.2 times (P < 0.05) and 2.9 times (P < 0.05) higher respectively. The expression of Col IV protein and mRNA was 3.8 times (P < 0.01) and 2.4 times (P < 0.01) higher respectively.

CONCLUSION

CTGF up-regulates FN and Col IV expression in MsC and may play an important role in the development of glomerulosclerosis.

[Protective effect of amifostine on cisplatin-induced nephrotoxicity and its mechanism]

OBJECTIVE

To investigate the sites and pattern of renal toxicity in rats treated with cisplatin and the protective effect of amifostine, and to understand whether Fas/FasL system is involved in cisplatin-induced nephrotoxicity.

METHODS

Forty-eight Sprague-Dawley rats were randomly divided into 3 groups: control group (0.9% saline solution), cisplatin group (6 mg/kg) and amifostine group (cisplatin 6 mg/kg + amifostine 200 mg/kg). Serum BUN and creatinine were measured by automatic biochemiscal analysis. Renal histopathological lesions were examined by light microscopy. TUNEL method was used for counting apoptotic cells. Immunohistochemistry and image analysis system were used for observing the expression of Fas/FasL system in renal tissues.

RESULTS

Compared with control group and amifostine group, serum BUN and creatinine were significantly elevated on day 3 (P < 0.05) and day 5 (P < 0.01 and P < 0.05, respectively), and recovered to normal on day 10. Severe necrosis and apoptosis of renal proximal tubular cells were revealed by elevated number of positively staining apoptotic cells examined by TUNEL method. Increased immunostaining intensity of Fas/FasL system in renal tissues in cisplatin-treated group was detected by immunohistochemistry and image analysis system.

CONCLUSION

Amifostine can reduce cisplatin-induced nephrotoxicity and its mechanism is probably associated with the suppression of Fas/FasL expression in renal tissues.

Study on the signalling pathway of inhibitory effect of adreno-medullin on the growth of cultured glomerular mesangial cells

BACKGROUND

Adrenomedullin (ADM), a potent hypotensive small peptide, was recently found to inhibit the proliferation of glomerular mesangial cells (MsC) in vitro and to attenuate glomerular lesions in vivo, however the mechanisms remain poorly understood. In this study, we attempted to elucidate them using molecular signal transduction.

METHODS

Cultured rat MsC were treated with ADM and several inhibitors of signalling molecules. Methyl thiazoleterazolium (MTT) assay and BrdU incorporation method were employed for examining MsC proliferation. Western blot analysis was used for detecting total mitogen activated protein kinases (t-MAPKs) and phosphorylated MAPKs (p-MAPKs) proteins.

RESULTS

ADM suppressed MsC proliferation in a concentration- and time-dependent fashion. This response was inhibited by ADM receptor antagonist CGRP8-37 and a potent protein kinase-A (PKA) inhibitor, H89. Forskolin, a direct adenylate cyclase activator, also significantly inhibited MsC proliferation. SB203580, a P38MAPK inhibitor, and U0126, a MEK inhibitor, both completely blocked ADM mediated responses in MsC. However, curcumin, a SAPK/JNK inhibitor, and GF109203X, a potent protein kinase-C (PKC) inhibitor, had no effect on MsC growth. Western blot analysis showed that ADM did not change the expression of t-MAPKs but increased p-SAPK/JNK and p-P38MAPK levels and decreased p-ERK level. These responses were inhibited by CGRP8-37. All these kinase phosphorylations, except for the increase in p-SAPK/JNK, could be stimulated using forskolin. In addition, only ADM mediated changes in ERK and P38MAPK phosphorylations were inhibited by H89. GF109203X did not affect ADM induced changes in three p-MAPKs expressions.

CONCLUSIONS

ADM inhibits MsC proliferation possibly through cAMP-PKA pathway. Both phosphorylations of ERK and P38MAPK pathways were necessary in mediating the antiproliferative response of ADM. It does not preclude the involvement of cAMP independent pathways in the ADM mediated responses.

[Effect of transforming growth factor beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 in cultured rat mesangial cells]

OBJECTIVE

To explore the effect of transforming growth factor (TGF) beta1/Smad signaling pathway on the expression and enzymatic activity of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) in cultured rat mesangial cells (MsC).

METHODS

Lipofectin method was used to transfect Smad 2, Smad 3 and Smad 7 vectors into MsC; and immunofluorescence, RT-PCR and Western blot analysis were used to detect their transfection efficiency. The expression and enzymatic activity of MMP-2 and TIMP-2 were determined by Western blot, zymography or reverse zymography assay.

RESULTS

MsC transfected with Smad 2 gene showed slightly increased expression and enzymatic activity of both MMP-2 and TIMP-2, which was more obvious upon stimulation by TGF-beta1. MsC transfected with Smad 3 gene showed a slight upregulation of TIMP-2 expression and its enzymatic activity, which was enhanced after TGF-beta1 stimulation. There was however no change in MMP-2 expression and its enzymatic activity. On the other hand, MsC transfected with Smad 7 gene showed a decrease in MMP-2 and TIMP-2 expression and enzymatic activity, which was especially obvious after stimulation by TGF-beta1.

CONCLUSIONS

TGF-beta1/Smad signaling pathway may play an important role in the pathogenesis of glomerulosclerosis, probably via MMP-2 and TIMP-2 expression and the associated enzymatic activity.

[Changes of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 expressions on cultured rat mesangial cells transfected with Smad 7 vector]

OBJECTIVE

To investigate matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase-2 (TIMP-2) expressions in the cultured rat mesangial cells (MsC) transfected with Smad 7 vector and to elucidate the mechanism of Smad 7 in blocking tissue fibrosis.

METHODS

Lipofectin method was used to transfect Smad 7 vector into MsC. Western blot and RT-PCR analyses were then used to detect Smad 7 protein and mRNA expression levels. The expressions of MMP-2 and TIMP-2 were determined by Western blot, RT-PCR and zymography assay.

RESULTS

Two MsC clones (S-22, S-26) with Smad 7 overexpression were successfully established. The two clones showed an increased expression of MMP-2 protein and enhanced enzyme activity. The expressions of TIMP-2 protein and mRNA however were suppressed.

CONCLUSIONS

It is possible that Smad 7 can alleviate the development of tissue fibrosis by upregulating the expression of MMP-2 and downregulating the expression of TIMP-2 in mesangial cells.

[The antagonistic effect on anti-thy-1 serum-induced nephritis of rats injected by decorin-transfected mesangial cells vector]

OBJECTIVES

To inject decorin-transfected mesangial cells (MsC) vector into the kidneys of rats with anti-thy-1 serum-induced nephritis via left renal artery and observe the survival condition of MsC vector and its influence on glomerular lesions in rats with anti-thy-1 serum induced nephritis.

METHODS

Rat mesangio-proliferative glomerulonephritis was established by tail intravenous injection with rabbit anti-thy-1 serum (ATS). Decorin-transfected MsC was injected into rat kidneys via left renal artery. Primary culture, immunostaining for BrdU and decorin of transfected MsC lines were performed to observe their survival. Immunohistochemistry with image analysis was performed to detect the expression of BrdU, alpha-SMA, decorin, TGF-beta1, FN and ColIV in diseased glomeruli.

RESULTS

Rat anti-thy-1 serum-induced nephritis identified by pathological examination was successfully established by injecting rabbit ATS, and decorin transfected MsC vector was transfused to rat glomeruli via left renal artery. The active growth and positive expressions of BrdU and decorin proteins on the nuclei and cytoplasms of ex vivo MsC were observed respectively. TGF-beta1, FN, ColIV expressions in diseased glomeruli of rats with ATS nephritis were decreased significantly at day 4 (TGF-beta1, P < 0.05) and day 2 (FN and ColIV, P < 0.01) respectively, compared to uninjected kidneys.

CONCLUSIONS

MsC vector is successfully transferred to the glomeruli of experimental rats via left renal artery injection with no affect on cell survival. Decorin protein is expressed on the transfected MsC and shows antagonistic effect on the glomerular lesions of ATS rats. It suggests that the use of ex vivo MsC vector system can provide useful experimental basis for gene therapy of kidney disease in animal model.

[Role of hepatitis B virus infection in pathogenesis of IgA nephropathy]

OBJECTIVE

To clarify the relationship between hepatitis B virus (HBV) infection and IgA nephropathy (IgAN).

METHODS

HBV antigen (HBAg) in renal tissues of the patients with IgAN was detected by immunohistochemical technique, the carrier status and localization of HBV DNA in renal tissues were determined by Southern blot analysis and in situ hybridization.

RESULTS

Serum HBsAg was detected in 18 of the 100 patients with IgAN (18%), HBAg was detected in 31 of 100 patients (31%) in their renal tissue and in 20 of 31 patients (65%) in their glomeruli, and both HBsAg and HBcAg were detected in 10 of 31 patients (32%), respectively. HBcAg was also found in tubular epithelia (45%, 14/31) and renal interstitium (6%, 2/31), respectively. Five of six cases were proved to be positive of integrated-form HBV DNA in their renal tissue by Southern blot analysis. In situ hybridization demonstrated that HBV DNA was 8/8 and 6/8 positive in their renal tubules and glomeruli of all eight specimens, localized in the nucleus of tubular epithelial cells, glomerular mesangial cells, as well as infiltrated interstitial lymphocytes.

CONCLUSION

HBV infection closely related with IgAN and HBV infection might be involved in pathogenesis of IgAN.

The localization of adrenomedullin in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells

OBJECTIVE

To observe the localization of adrenomedullin (AM) in rat kidney tissue and its inhibitory effect on the growth of cultured rat mesangial cells (MsC).

METHODS

A monoclonal antibody against AM developed by our laboratory was used to detect the localization of AM protein in rat kidney tissue by avidin-biotin complex immunohistochemistry. The expressions of AM and its receptor CRLR mRNA on cultured glomerular epithelial cells (GEC) and MsC were investigated by Northern blot assay, and the possible effect of AM secreted by GEC on MsC proliferation was observed using [3H]thymidine incorporation as an index.

RESULTS

A specific monoclonal antibody against AM was succesfully developed. AM was immunohistochemically localized mainly in glomeruli (GEC and endothelial cells), some cortical proximal tubules, medullary collecting duct cells, interstitial cells, vascular smooth muscle cells and endothelial cells. Northern blot assay showed that AM mRNA was expressed only on cultured GEC, but not on MsC, however, AM receptor CRLR mRNA was only expressed on MsC. GEC conditioned medium containing AM can inhibit MsC growth and AM receptor blocker CGRP8-37 may partially decreased this inhibitory effect.

CONCLUSION

AM produced by GEC inhibits the proliferation of MsC, which suggests that AM as an important regulator is involved in glomerular normal physiological functions and pathologic processes.

[The expressions of TGF-beta1 and Smad 2 mRNA on diseased glomeruli and their significance in the development of glomerulosclerosis]

OBJECTIVE

To explore the expressions of transforming growth factor-beta1 (TGF-beta1) and its signaling transduction molecule Smad 2 and their significance in the development of glomerulosclerosis.

METHODS

Using in situ hybridization and immunohistochemistry to detect Smad 2 mRNA expression and TGF-beta1, collagen IV, fibronectin expression in renal biopsies from 61 cases with a spectrum of glomerulonephritis including IgA nephropathy (40 cases), membranous glomerulonephritis (10 cases) and sclerosing glomerulonephritis (11 cases), compared with 11 cases of glomerular mild lesion with image analysis system.

RESULTS

With the exception of Smad 2 mRNA expression in mild type IgA nephropathy, all other types of diseased glomeruli showed increased expression of both TGF-beta1 and Smad 2 mRNA when compared with the 11 cases of mild glomerular lesions. The expressions of glomerular TGF-beta1 and Smad 2 mRNA positively correlated with collagen IV and fibronectin deposition in the glomeruli.

CONCLUSIONS

TGF-beta1 and Smad 2 may be involved in the excessive deposition of glomerular extracellular matrix and play an important role in the development of glomerulosclerosis.

Effect of suppression of TGF-beta1 expression on cell-cycle and gene expression of beta-1,4-galactosyltransferase 1 in human hepatocarcinoma cells

beta-1,4-galactosyltransferase 1 (beta1,4-GT 1) is localized both in the Golgi complex where it catalyzes the transfer of galactose from UDP-galactose to terminal N-acetylglucosamine forming Galbeta1 --> 4GlcNAc structure, and on the cell surface where it serves as an adhesion molecule. It has previously been reported that the expression of beta1,4-GT 1 was cell-cycle-specific, regulated by cell growth. Transforming growth factor-beta1 (TGF-beta1) could regulate cell G1/S phase transition and modulate cell growth in many types of cells. In this study, we introduced the antisense-TGF-beta1 into SMMC-7721 cell, a human hepatocarcinoma cell line, for blocking its intrinsic TGF-beta1 expression, and changing its cell-cycle, and then analyzed the gene expression of beta1,4-GT 1 together with the beta1,4-GT activity. The result showed that the antisense-TGF-beta1 transfected SMMC-7721 cells (AST/7721) were growth enhanced, with more cells in S phase and less cells in G2/M phase compared with the mock transfected cells (pcDNA3/7721). At the same time, it was found that the gene expression of beta1,4-GT 1 in AST/7721 was decreased to one fifth that of pcDNA3/7721, and the cell surface beta1,4-GT activity was reduced to one fifth of the control, while the total activity of beta1,4-GT was decreased to one half that of the control. The results indicate that suppression of TGF-beta1 expression resulted in change of cell-cycle together with the decreased gene expression of beta1,4-GT 1 and beta1,4-GT activity in human hepatocarcinoma cells.

In situ hybridization of hepatitis B DNA in hepatitis B-associated glomerulonephritis

Renal tissues from 43 of 49 children with hepatitis B virus-associated glomerulonephritis (HBV-GN) were examined for HBV DNA by in situ hybridization (ISH) assay within the last 10 years. HBV DNA was identified in 41 of the 43 cases (95.3%). HBV DNA was distributed generally in the nucleus and cytoplasm of epithelial cells and mesangial cells of glomeruli, and epithelial cells of renal tubules. HBV DNA also existed simultaneously in renal interstitial tissues in some of these cases. The positive results from HBV DNA ISH correlated well with HBV antigen assays. The analyses implied that the more extensive the existence of HBV DNA in the nephron unit and interstitial tissue, the more severe the clinical manifestation. The duration of proteinuria in cases with HBV DNA in renal tubules was much longer than in those with no HBV DNA in renal tubules. The persistence of the HBV genome or genes in the kidney could lead to the expression of viral antigens in renal tissues and might cause cellular pathological alteration. This would support utilization of antiviral therapy, such as cytokines, in the treatment of HBV-GN.

[Further study on the immunopathology of hepatitis B virus associated glomerulonephritis]

By using immunohistochemical techniques the deposition of HBV associated immune complexes was studied in 845 consecutive cases of renal biopsy. In 665 cases of primary glomerulonephritis the frequencies of HBsAg, HBeAg and HBcAg detection in glomeruli were 11.9%, 8.3% and 3.2% respectively with a total HBV antigen positive frequency of 12.2%. High positive rates were found in membranous glomerulonephritis (MGN, 37.1%), mesangioproliferative GN (MPGN, 26%) and IgA nephropathy (IgA-NP, 18.9%). The detection of HBV infection markers in serum were simultaneously performed in 213 cases; 31.7% of the patients with primary GN were found to be positive. In patients with positive HBV infectious markers in the serum, deposits of HBV antigens in glomeruli were found in 49.1% of the cases. The incidence was significantly different in the serum negative group (10.6%). Meanwhile, about 68.3% of the cases with HBV antigen deposits in the kidney was found to have positive HBV markers in the serum. Also the incidence was significantly different in the group without HBV antigen deposits in the kidney (20.9%). It was again confirmed that the pathogenesis of hepatitis B virus associated glomerulonephritis (HBV-GN) was related to the deposition of HBV immune complexes in kidney tissue. It was noticed that the deposition of three different types of HBV antigens was somewhat associated with the development of specific forms of HBV GN. The diagnostic criteria of HBV-GN were discussed in detail.

[Immunohistochemical study of the expression of major histocompatibility complex (MHC)-determined antigens in renal tissue of MRL/lpr mice]

Expression of MHC antigens in renal tissue of MRL/lpr(H-2K) mice were demonstrated by monoclonal antibodies against class I(KK) and class II(IAK) antigens and ABC immunoperoxidase method. The expression of KK antigen in glomeruli, tubules and vessels of kidney and IAK antigen in glomeruli tubules was stronger in mice fed with beef tallow diet after gamma-interferon treatment than in the control group. This result suggests that using of gamma-interferon may enhance the presentation of MHC antigens in renal tissue of MRL/lpr mice. In mice raised with Menhaden fish oil diet after gamma-interferon treatment, however, the enhancement of expression of IAK antigen was detected only in renal tubules. In comparing with mice fed with beef tallow after gamma-interferon injection, the expression of KK antigen in glomeruli, vessels and IAK in the dendritic cells of renal interstitium was weaker in mice fed with fish oil. This result indicates that fish oil can more or less inhibit the expression of MHC antigens in renal tissue of mice. The mechanism of the inhibitory action of fish oil remains to be elucidated.