LRRC25 plays a key role in all-trans retinoic acid-induced granulocytic differentiation as a novel potential leukocyte differentiation antigen

Leukocyte differentiation antigens (LDAs) play important roles in the immune system, by serving as surface markers and participating in multiple biological activities, such as recognizing pathogens, mediating membrane signals, interacting with other cells or systems, and regulating cell differentiation and activation. Data mining is a powerful tool used to identify novel LDAs from whole genome. LRRC25 (leucine rich repeat-containing 25) was predicted to have a role in the function of myeloid cells by a large-scale "omics" data analysis. Further experimental validation showed that LRRC25 is highly expressed in primary myeloid cells, such as granulocytes and monocytes, and lowly/intermediately expressed in B cells, but not in T cells and almost all NK cells. It was down-regulated in multiple acute myeloid leukemia (AML) cell lines and bone marrow cells of AML patients and up-regulated after all-trans retinoic acid (ATRA)-mediated granulocytic differentiation in AML cell lines and acute promyelocytic leukemia (APL; AML-M3, FAB classification) cells. Localization analysis showed that LRRC25 is a type I transmembrane molecule. Although ectopic LRRC25 did not promote spontaneous differentiation of NB4 cells, knockdown of LRRC25 by siRNA or shRNA and knockout of LRRC25 by the CRISPR-Cas9 system attenuated ATRA-induced terminal granulocytic differentiation, and restoration of LRRC25 in knockout cells could rescue ATRA-induced granulocytic differentiation. Therefore, LRRC25, a potential leukocyte differentiation antigen, is a key regulator of ATRA-induced granulocytic differentiation.

Expression and Significance of CMTM3 in Helicobacter pylori Infected Chronic Gastritis / 胃肠病学

Background: CKLF-like MARVEL transmembrane domain containing (CMTM) superfamily is involved in the occurrence and development of inflammation, cancer and a variety of diseases.Human CMTM3 has been proposed as a putative tumor suppressor gene.Aims: To investigate the expression of CMTM3 in Helicobacter pylori (Hp) infection-related chronic gastritis and its significance.Methods: Sixty cases of outpatients with chronic gastritis (30 Hp-positive and 30 Hp-negative) were enrolled for detection of CMTM3 and interleukin-6 (IL-6) expressions in gastric mucosa by immunohistochemistry.The correlation of expressions of CMTM3 and IL-6 was analyzed.Results: The positivity rates of CMTM3 and IL-6 in gastric mucosa were significantly higher in Hp-positive chronic gastritis than in Hp-negative ones (CMTM3: 63.3% vs.30.0%, P<0.05;IL-6: 73.3% vs.13.3%, P<0.01).In patients with Hp-positive chronic gastritis, CMTM3 and IL-6 were co-expressed in 53.3% (16/30) of the patients and localized in the same position.Expression of CMTM3 was positively correlated with IL-6 expression in Hp-positive chronic gastritis patients (r=0.58, P<0.05).Conclusions: CMTM3 is highly expressed in chronic gastritis patients with Hp infection.It may participate in the occurrence and development of Hp infection-related chronic gastritis with inflammatory cytokines such as IL-6.Hp infection might be one of the mechanisms involved in CMTM3 up-regulation.

Preparation and characterization of the antibodies against human myofibrillogenesis regulator 1 and application in neonatal rat cardiomyocytes / 中国病理生理杂志

AIM: To prepare and purify the polyclonal antibodies against human myofibrillogenesis regulator 1 (hMR-1), then to characterize the purity, titer, specificity and the availability.METHODS: Two polypeptides named peptide 1 and 2 were synthesized based on the bioinformatics analysis of the sequence of hMR-1 by using software TMHMM and DNAStar, then coupled with keyhole limpet hemocyanin (KLH) for immunization. These peptides for immunization were mixed and injected into New Zealand rabbits to prepare antibodies specifically against hMR-1. ELISA assay was used to detect the titers of the antibodies. After purification by immunoaffinity chromatography, antibodies were identified by Western blotting and immunocytofluorescent assays. Applications of the antibodies on neonatal rat cardiomyocytes were also employed.RESULTS: (1)The titers of antibodies were 1:10~5. In WB assay, a specific 17kD band was detected, corresponding to the predicted molecular weight of hMR-1; the positive fluorescent signals were distinct. (2)On the neonatal rat cardiomyocytes model, we observed a peri-nucleus location. The fluorescent signal of hMR-1 overexpression group was much stronger than that in vector control and normal control groups.CONCLUSION: All these results indicate that the antibodies obtained from poly peptides mixture immunization have either human original or rat original antigens. The antibody is available for using in Western blotting or immunofluorescent assays.

Expression and functional study of human recombinant chemokine-like factor I in Drosophila S2 cells / 中华微生物学和免疫学杂志

Objective To express human chemokine-like factor 1 (CKLF1) in Drosophila S2 cells and study its function. Methods The pMT/V5-His-CKLF1 expression plasmid was constructed and transfected into Drosophila S2 cells. The positive clones were selected through PCR and RT-PCR. The culture medium was analyzed by Western blot with anti-CKLF1 polyclonal antibody. Chemotaxis and MTT assays on human peripheral blood and C2C12 cells, respectively, were then carried out with the medium. Results CKLF1 was transcribed efficiently in S2 cells. The expressed CKLF1 protein could be detected in the culture supernatant by Western blot, which showed weak chemotactic activity on both human peripheral blood neutrophils and lymphocytes as well as enhancing effect on the proliferation of C2C12 cells. Conclusion CKLF1 was expressed successfully in Drosophila S2 cells and secreted into the culture medium. The recombinant CKLF1 expressed in Drosophila cells can chemoattract leucocytes and promote the proliferation of C2C12 cells.

Effects of chemokine-like faotor 1 (CKLF1) on proliferation and metabolism of chondrocytes / 北京大学学报(医学版)

Objective: To investigate the effects of chemokine like factor 1 (CKLF1) on proliferation and metabolism of chondrocytes. Methods: Cell culture, 3H TdR and 3H Proline incorporation methods were used. Chondrocytes were harvested from rabbit articular cartilage. First passage cells were seeded on 96 well plates. After synchronization,the medium was replaced by DMEM containing 5% FCS with various concentration of CKLF1 conditioned medium. The synthesis of mucopolysaccharide was detected by Saffraan O staining. The transcription of inducible nitricoxide synthase (iNOS) was detected by semi quantitative RT-PCR. Results: CKLF1 inhibited the DNA, collagen and mucopolysaccharide synthesis significantly, meanwhile, stimulated the transcription of iNOS. Conclusion: CKLF1 inhibits the proliferation and matrix synthesis of chondrocytes, which might be an important factor resulting in cartilage destructive lesions. CKLF1 may exert its effects on chondrocytes through iNOS pathway.

Nuclear translocation of apoptosis-related protein TFAR19 in TF-1 cells undergoing apoptosis / 北京大学学报(医学版)

Objective: To study the expression and localization of apoptosis-related protein TFAR19 in TF-1 cells undergoing apoptosis. Methods: Using monoclonal antibody against TFAR19, the expression level and cell localization of TFAR19 were examined by fluorescence microscope, confocal laser scan microscope(CLSM) and flow cytometry. Simultaneously, we also analyzed the relationship of TFAR19 protein with phosphatidylserine (PS) externalization and cell nuclear DNA fragmentation. Results: The level of TFAR19 proteins expressed in TF-1 cells treated with GM-CSF withdrawal was significantly increased compared with normal TF-1 cells, then translocated rapidly from cytoplasm to the nucleus of cells. Appearance of TFAR19 in the nucleus of apoptotic cells preceded the detection of PS externalization and DNA fragmentation. Conclusion: Nuclear translocation of TFAR19 protein is one of the earliest events of cell apoptotic process. These data provided a new clue to further approach to the biological function of TFAR19 and study of cell apoptosis.