[Estradiol significantly increases the expression of antioxidant enzymes in osteoporotic rats and osteoblasts in vitro]

OBJECTIVE

To investigate the effect of estradiol on the expression of antioxidant enzymes in osteoblasts and its role in postmenopausal osteoporosis.

METHODS

Rat models of osteoporosis established by ovariectomy were treated with estradiol for 3 months, and the changes in serum levels of reactive oxygen species (H₂O₂) and antioxidant enzymes (γ -GCS, GSH-ST and GSH-px) were detected. The effects of estradiol on the expression of γ -GCS mRNA and protein in osteoblast-like cells MC3T3-E1, MG63 and OB were examined with PCR and Western blotting. Using a mRNA microarray, we analyzed the changes in the expressions of 84 antioxidant enzymes in the osteoblast cell line MC3T3-E1 following estradiol treatment, and the enzymes with significant changes were verified by PCR. CCK-8 kit was used to evaluate the effect of estradiol and antioxidant NAC on the proliferation of MC3T3-E1 cells.

RESULTS

Rat models of osteoporosis were successfully established with ovariectomy. The osteoporotic rats showed significantly increased serum level of reactive oxygen species (H2O2) and decreased levels of antioxidant enzymes. Estrogen treatment of the osteoporotic rats obviously reversed the phenotype of osteoporosis, lowered serum level of reactive oxygen species, and increased the level of γ -GCS. In MC3T3-E1, MG63 and OB cells, estradiol treatment significantly upregulated the expression levels of γ -GCS mRNA and protein. In MC3T3-E1 cells treated with estrogen, the mRNA chip identified 6 upregulated antioxidant enzymes (Gpx6, Gstk1, Nos2, Prdx2, Ngb and Ccs), and the results of PCR verified that estradiol upregulated Ccs and Ngb mRNAs in MC3T3-E1, MG63 and OB cells. Estradiol and antioxidant NAC obviously promoted the proliferation of MC3T3-E1 cells.

CONCLUSION

Estradiol significantly increases the expression of antioxidase γ -Gcs, Ccs and Ngb in osteoblasts in vitro. Postmenopausal osteoporosis is closely related with the increase of reactive oxygen species and the decrease of antioxidant levels. In osteoblasts, estrogen deficiency may increase the level of reactive oxygen species, decrease the level of antioxidant enzymes, activate the oxidative stress cascade, and consequently inhibit the proliferation of osteoblasts to aggravate the condition of osteoporosis.

[A method for efficient transduction of miR-483-5p in the kidney of mice]

OBJECTIVE

To establish a method for gene delivery in murine renal tissue using lentivirus vector encoding miR-483-5p.

METHODS

Thirty-five C57BL/6J mice were randomly divided into control group, low-dose treatment group (5 µL each kidney) , and high?dose treatment group (20 µL each kidney), and in the latter two groups, the lentivirus vector encoding miR-483-5p were injected in the renal cortex. The tissue samples were collected at 7 and 21 days after the injection. A transgenic mouse model with inducible systemic overexpression of miR-483-5p was established in TG483 mice. The Cre-loxp system was used to create a mouse model with renal tubule-specific expression of miR-483-5p. The levels of BUN in the mice were detected and HE staining and fluorometric TUNEL assay were used to observe the morphological changes of the kidneys; real-time qPCR was used to detect miR-483-5p expression in the renal cortex.

RESULTS

The mice with overexpression of miR-483-5p had normal renal function without obvious pathological changes or apoptosis in the renal tissue. Renal cortex injection of 20 µL lentivirus resulted in obviously increased level of miR-483-5p at 21 days (1.2∓0.43 vs 8.6∓1.09, P<0.001). miR-483-5p showed a low expression (0.9∓0.09 vs 1.7∓0.19, P<0.05) in TG483 mice and a high expression in the kidney of the transgenic mice established using the Cre-loxp system (1.6∓1.13 vs 12.36∓3.89, P<0.05).

CONCLUSION

The transgenic mice with renal tubule-specific expression of miR-483-5p show normal renal function, and this model facilitates further study of the role of miR-483-5p in the kidney.

[JAG1 promotes migration, invasion, and adhesion of triple-negative breast cancer cells by promoting angiogenesis]

OBJECTIVE

To investigate the effect of JAG1 on the malignant phenotype of triple-negative breast cancer (TNBC) and its role in angiogenesis in breast cancer microenvironment.

METHODS

The expressions of Notch molecules were detected in human TNBC 231 and 231B cells using RT-qPCR. Five female nude mice were inoculated with 231 cells and another 5 with 231B cells into the mammary fat pads, and 4-6 weeks later, the tumors were collected for immunohistochemical and immunofluorescence tests. 231 cells and 231B cells were treated with recombinant JAG (rJAG) protein and DAPT, respectively, and changes in their malignant phenotypes were assessed using CCK-8 assay, Hoechst 33258 staining, wound healing assay, Transwell chamber assay and endothelial cell adhesion assay. Western blotting was used to detect the changes in the expressions of proteins related with the malignant phenotypes of 231 and 231B cells. The effects of conditioned medium (CM) derived from untreated 231 and 231 B cells, rJAG1-treated 231 cells and DAPT-treated 231B cells on proliferation and tube formation ability of cultured human umbilical vein endothelial cells (HUVECs) were evaluated using CCK-8 assay and tube-forming assay.

RESULTS

The expression of JAG1 was higher in 231B cells than in 231 cells (P < 0.05). Tumor 231B showed higher expression of VEGFA and CD31. Compared with 231-Blank group, the migration, invasion and adhesion of 231 cells in 231-rJAG1 were significantly enhanced (P < 0.05). Protein levels of Twist1 and Snail increased (P < 0.01), anti-apoptotic protein Bcl-2 increased (P < 0.05), while DAPT inhibited the related phenomena and indicators of 231B. The 231-rJAG1-CM increased the cell number and tubule number of HUVEC (P < 0.05).

CONCLUSION

JAG1 may affect the malignant phenotype of TNBC and promote angiogenesis in the tumor microenvironment.

[Association of the ADCY9 gene and gene-environmental interaction with the susceptibility to childhood bronchial asthma]

OBJECTIVES

To study the association of the single nucleotide polymorphisms (SNPs) of the adenylyl cyclase IX (ADCY9) gene at rs1967309, rs2230739, rs2601814, rs2601825, rs2601796, and rs2283497 loci and gene-environment interaction with childhood bronchial asthma (asthma for short).

METHODS

A total of 123 children with asthma who attended the hospital from March 2019 to September 2021 were enrolled as the asthma group, among whom 84 (68.3%) had mild-to-moderate attacks and 39 (31.7%) had severe attacks. A total of 124 healthy children were enrolled as the control group. The association of the SNPs and haplotypes of the ADCY9 gene at the above 6 loci with the susceptibility to childhood asthma was evaluated. The method of generalized multifactor dimensionality reduction was used to analyze gene-environment interaction.

RESULTS

Polymorphisms were observed for the ADCY9 gene at the above six loci in both the asthma and control groups, and there were significant differences in genotype and allele frequencies at the rs1967309 locus between the two groups (P<0.05). There was no significant difference in the distribution frequency of haplotypes TA and GG between the asthma and control groups (P>0.05). The generalized multifactor dimensionality reduction analysis showed interaction between rs1967309 locus and allergen contact (P<0.05), which increased the risk of asthma (OR=1.585, P<0.05).

CONCLUSIONS

The rs1967309 locus of the ADCY9 gene is associated with the susceptibility to childhood asthma, and the locus and allergen contact have a synergistic effect on the development of asthma.

[JAG1 affects monocytes-macrophages to reshape the pre-metastatic niche of triple-negative breast cancer through LncRNA MALAT1 in exosomes]

OBJECTIVE

To investigate the effect of JAG1 on the activities of monocytes-macrophages in pre-metastatic niche (PMN) of triple-negative breast cancer (TNBC) and explore the possible regulatory mechanism.

METHODS

JAG1 expression in human TNBC MDA-MB-231 and MDA-MB-231B cells was detected using quantitative real-time PCR (qRT-PCR).Ten female nude mice were inoculated with MDA-MB-231 cells (n=5) or MDA-MB-231B cells (n=5) in the mammary fat pad, and 6 weeks later, the tumor tissues were collected for immunohistochemistry.Human monocytes THP-1 cells were treated with rhJAG1 or conditioned media (CM) of TNBC MDA-MB-231 and MDA-MB-231B cells to assess the direct effect of JAG1 on monocytes and its effect on monocytes in the PMN using monocyte-endothelial adhesion, Transwell assay, qRT-PCR and Western blotting.Transmission electron microscopy and nanoparticle tracking analyses were used to identify the effect of JAG1 on exosome release from the TNBC cells.MiRNAs interacting with lncRNA MALAT1 were identified by bioinformatics and validated using qRT-PCR.

RESULTS

Compared with MDA-MB-231 cells, the invasive strain MDA-MB-231B cells showed significantly higher JAG1 expression and greater liver metastasis potential (P<0.01).Both direct treatment with rhJAG1 and treatment with the conditioned media promoted adhesion and migration and affected differentiation of the monocytes (P<0.05).Transmission electron microscopy and nanoparticle tracking analysis showed that JAG1 strongly enhanced exosome secretion from MDAMB-231 cells (P<0.01) and increased MALAT1 content in the exosomes (P<0.0001).Five candidate miRNAs related to MALAT1 and JAG1 were identified by bioinformatics analysis, and miR-26a-5p was identified as a potential target of MALAT1 in monocytes-macrophages in TMN (P<0.0001).

CONCLUSION

JAG1 can promote exocrine secretion of TNBC and increase the expression of MALAT1 to cause targeted downregulation of miR-26a-5p in monocytes-macrophages in the PMN, which in turn increases JAG1 expression in monocytes-macrophages to affect their adhesion, migration and osteoclast differentiation in the PMN.

[Estradiol significantly increases the expression of antioxidant enzymes in osteoporotic rats and osteoblasts in vitro]

OBJECTIVE

To investigate the effect of estradiol on the expression of antioxidant enzymes in osteoblasts and its role in postmenopausal osteoporosis.

METHODS

Rat models of osteoporosis established by ovariectomy were treated with estradiol for 3 months, and the changes in serum levels of reactive oxygen species (H2O2) and antioxidant enzymes (γ -GCS, GSH-ST and GSH-px) were detected. The effects of estradiol on the expression of γ -GCS mRNA and protein in osteoblast-like cells MC3T3-E1, MG63 and OB were examined with PCR and Western blotting. Using a mRNA microarray, we analyzed the changes in the expressions of 84 antioxidant enzymes in the osteoblast cell line MC3T3-E1 following estradiol treatment, and the enzymes with significant changes were verified by PCR. CCK-8 kit was used to evaluate the effect of estradiol and antioxidant NAC on the proliferation of MC3T3-E1 cells.

RESULTS

Rat models of osteoporosis were successfully established with ovariectomy. The osteoporotic rats showed significantly increased serum level of reactive oxygen species (H2O2) and decreased levels of antioxidant enzymes. Estrogen treatment of the osteoporotic rats obviously reversed the phenotype of osteoporosis, lowered serum level of reactive oxygen species, and increased the level of γ -GCS. In MC3T3-E1, MG63 and OB cells, estradiol treatment significantly upregulated the expression levels of γ -GCS mRNA and protein. In MC3T3-E1 cells treated with estrogen, the mRNA chip identified 6 upregulated antioxidant enzymes (Gpx6, Gstk1, Nos2, Prdx2, Ngb and Ccs), and the results of PCR verified that estradiol upregulated Ccs and Ngb mRNAs in MC3T3-E1, MG63 and OB cells. Estradiol and antioxidant NAC obviously promoted the proliferation of MC3T3-E1 cells.

CONCLUSION

Estradiol significantly increases the expression of antioxidase γ -Gcs, Ccs and Ngb in osteoblasts in vitro. Postmenopausal osteoporosis is closely related with the increase of reactive oxygen species and the decrease of antioxidant levels. In osteoblasts, estrogen deficiency may increase the level of reactive oxygen species, decrease the level of antioxidant enzymes, activate the oxidative stress cascade, and consequently inhibit the proliferation of osteoblasts to aggravate the condition of osteoporosis.

[Loss of Myeloid-Derived Growth Factor Leads to Increased Fibrosis in Mice After Myocardial Infarction]

Objective

To investigate the effect of the loss of myeloid-derived growth factor (Mydgf) on the transformation of cardiac fibroblasts into myofibroblasts after myocardial infarction (MI).

Methods

Two adult mouse groups, including a wild-type (WT) group and another group with Mydgf knockout (Mydgf-KO), were examined in the study. The mice in these two groups were tested for their cardiac function by measuring left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) (n=10). Quantitative real-time PCR (qRT-PCR) (n=3) was performed to determine the mRNA expression levels of myofibroblast markers, including α-smooth muscle actin (α-SMA), periostin (postn), type Ⅷ collagen (col8al), and connective tissue growth factor (ctgf). Western blot (n=3) was performed to verify the protein expression levels of α-SMA. MI modeling was performed on the WT and the Mydgf-KO mice. Postoperative LVEF and LVFS (n=10) were then measured. The hearts were harvested and Masson staining was performed to determine the infarcted area (n=10). The heart samples of Mydgf-KO and WT mice were collected at d 7 and d 14 after MI, respectively, to verify the expression of myofibroblast markers (n=3).

Results

Compared with WT mice, LVEF and LVFS in adult Mydgf-KO mice showed no significant changes (all P>0.05). However, the mRNA levels of α-SMA and postn were upregulated, and α-SMA protein expression was also increased (all P<0.05). After MI, compared with WT mice, LVEF and LVFS in Mydgf-KO mice decreased, and the infarcted area increased significantly (all P<0.05). Furthermore, mRNA levels of α-SMA, col8al, postn, and ctgf were increased in Mydgf-KO mice. In addition, the α-SMA protein expression level was upregulated and α-SMA-positive fibroblasts were increased (P<0.05).

Conclusion

Mydgf deletion promotes the transformation of cardiac fibroblasts into myofibroblasts and aggravates myocardial fibrosis after MI.

Efficacy of intermittent iron supplementation in children with mild iron-deficiency anemia

OBJECTIVES

To study the efficacy of intermittent iron supplementation in children with mild iron-deficiency anemia.

METHODS

A total of 147 children with mild iron-deficiency anemia were enrolled in this prospective study. They were divided into an intermittent iron supplementation group (n=83) and a conventional iron supplementation group (n=64). The levels of hemoglobin were measured before treatment and after 1 and 3 months of treatment. The treat response rate and the incidence rate of adverse drug reactions were compared between the two groups.

RESULTS

Both groups had a significant increase in the level of hemoglobin after iron supplementation (P<0.05). After 1 month of treatment, the conventional iron supplementation group had a significantly higher treatment response rate than the intermittent iron supplementation group (61% vs 42%, P<0.05). After 3 months of treatment, there was no significant difference in the treatment response between the two groups (86% vs 78%, P>0.05). The incidence rate of adverse drug reactions in the conventional iron supplementation group was significantly higher than that in the intermittent iron supplementation group (25% vs 8%, P<0.05).

CONCLUSIONS

For children with mild iron-deficiency anemia, although intermittent iron supplementation is inferior to conventional iron supplementation in the short-term efficacy, there is no significant difference in the long-term efficacy between the two methods, and compared with conventional iron supplementation, intermittent iron supplementation can reduce the incidence of adverse drug reactions, alleviate family financial burdens, and improve treatment compliance of children, thus holding promise for clinical application.

[Expression of kinesin KIF3A in the kidney of mice with unilateral ureteral obstruction]

OBJECTIVE

To investigate the expression of KIF3A in mice with unilateral ureteral obstruction (UUO) and TGF-β1-induced NRK-52E cells and the role of KIF3A in renal tubular epithelial cell transdifferentiation.

METHODS

Thirty-six C57BL/6J mice were randomly divided into the sham group (n=18) and UUO group (n=18). Six mice in each group were sacrificed at 7, 14 and 21days after the operation. The degree of renal tubulointerstitial fibrosis of the mice was observed by HE staining, Masson trichrome staining and Sirius red staining. The expression and distribution of KIF3A in the kidney of the mice was detected using RT-PCR, Western blotting and immunohistochemistry. Western blotting was used to detect the expression of KIF3A, E-cadherin and α-SMA proteins in the renal tissue of the mice. The expressions of KIF3A, E-cadherin, α-SMA, Wnt4 and β-catenin proteins in NRK-52E cells with TGF-β1-induced transdifferentiation were detected by Western blotting.

RESULTS

Compared with the sham-operated mice, the mice with UUO showed worsened renal interstitial fibrosis with the increase of obstruction time, indicating successful modeling. The expressions of KIF3A mRNA and protein increased progressively and reached the peaked level at 21 days after UUO. The expression of α-SMA protein was significantly increased while E-cadherin protein expression was significantly reduced after UUO. The transdifferentiated NRK-52E cells showed significantly increased expressions of KIF3A (P < 0.001), Wnt4 (P < 0.05) and β-catenin proteins (P < 0.0001).

CONCLUSIONS

KIF3A may participate in the development of renal fibrosis through epithelial-mesenchymal transition mediated by wnt/β-catenin signaling pathway.

[A method for efficient transduction of miR-483-5p in the kidney of mice]

OBJECTIVE

To establish a method for gene delivery in murine renal tissue using lentivirus vector encoding miR-483-5p.

METHODS

Thirty-five C57BL/6J mice were randomly divided into control group, low-dose treatment group (5 µL each kidney) , and high?dose treatment group (20 µL each kidney), and in the latter two groups, the lentivirus vector encoding miR-483-5p were injected in the renal cortex. The tissue samples were collected at 7 and 21 days after the injection. A transgenic mouse model with inducible systemic overexpression of miR-483-5p was established in TG483 mice. The Cre-loxp system was used to create a mouse model with renal tubule-specific expression of miR-483-5p. The levels of BUN in the mice were detected and HE staining and fluorometric TUNEL assay were used to observe the morphological changes of the kidneys; real-time qPCR was used to detect miR-483-5p expression in the renal cortex.

RESULTS

The mice with overexpression of miR-483-5p had normal renal function without obvious pathological changes or apoptosis in the renal tissue. Renal cortex injection of 20 µL lentivirus resulted in obviously increased level of miR-483-5p at 21 days (1.2∓0.43 vs 8.6∓1.09, P<0.001). miR-483-5p showed a low expression (0.9∓0.09 vs 1.7∓0.19, P<0.05) in TG483 mice and a high expression in the kidney of the transgenic mice established using the Cre-loxp system (1.6∓1.13 vs 12.36∓3.89, P<0.05).

CONCLUSION

The transgenic mice with renal tubule-specific expression of miR-483-5p show normal renal function, and this model facilitates further study of the role of miR-483-5p in the kidney.