High-salt diet accelerates bone loss accompanied by activation of ion channels related to kidney and bone tissue in ovariectomized rats.

Excessive salt intake can induce a variety of diseases, such as hypertension, cardiovascular disease, kidney disease and so on，it is also one of the factors promoting bone resorption. The mechanism of osteoporosis-induced exacerbations of high salt diet is not well-defined. In this study, we used ovariectomized 6-month-old Sprague Dawley rats to construct a high bone turnover model, and then administrated with high sodium chloride diet (2.0% w/w NaCl, 8.0% w/w NaCl) for 12 weeks to observe the effect of high salt diet on bone metabolism. The results showed that high salt diet could lead to the destruction of bone microstructure, promote the excretion of urinary calcium and phosphorus and accelerate the bone turnover, as well as cause the pathologic structural abnormalities in renal tubular. At the same time, it was accompanied by the up-regulated expression of the epithelial sodium channel (ENaCα), voltage-gated chloride channels (ClC)- 3 and the down-regulated expression of Na-Cl cotransporter (NCC), sodium calcium exchanger (NCX1) in femoral tissue and renal tubules. These findings confirm that high salt diet can destroy the microstructure of bone by increasing bone resorption and affect some ion channels of bone tissue and renal tubule in ovariectomized rats.

Effects of cadmium on osteoblast cell line: Exportin 1 accumulation, p-JNK activation, DNA damage and cell apoptosis.

Cadmium is an environmental metal pollutant that has been a focus of research in recent years, which is reported to cause bone disease; however, its skeletal toxicity and the mechanism involved are not yet fully known. Therefore, this study used MC3T3-E1 subclone 14 cells to determine the mechanism of cadmium toxicity on bone. Cadmium chloride (Cd) significantly reduced cell viability in a concentration-dependent manner. Exposure to Cd inhibited osteoblast-related proteins (Runx2, Col-1, STC2) and decreased alkaline phosphatase (ALP) activity. Cd caused Exportin-1 accumulation and induced DNA damage. Cd significantly down-regulated caspase 9 and induced cleaved-PARP, cleaved-caspase 3 protein level. Treatment with JNK inhibitor, SP600125, suppressed cadmium-induced elevation in the ratio of phosphorylation of JNK to JNK. Inhibition of caspase with pan-caspase inhibitor, Z-VAD-FMK, prevented MC3T3-E1 subclone 14 cells from cadmium-induced reduction of Runx2, STC2, caspase 9, and accumulation of cleaved PARP and cleaved caspase 3. Cd-induced cell survival enhanced by SP600125 but rescued by Z-VAD-FMK or KPT-335. These results suggest that cadmium cytotoxicity on bone involved exportin 1 accumulation, phosphorylation of JNK, induction of DNA damage and pro-apoptosis, which was induced by activation of caspase-dependent pathways.

High sodium chloride affects BMP-7 and 1α-hydroxylase levels through NCC and CLC-5 in NRK-52E cells.

A diet high in sodium chloride (NaCl) can affect renal function damage and increase urinary calcium excretion, leading to bone loss. in renal tubules, Na-Cl co-transporter (NCC) and chloride channel 5 (CLC-5) are involved in regulating urinary calcium excretion. In addition, some cytokines, such as Bone morphogenetic protein 7 (BMP-7) and 1α-hydroxylase, are synthesized by renal tubules, which target on bone and play important roles on bone metabolism. However, the specific mechanisms between NaCl and these ion channels or cytokines still need investigations from many aspects. This study, in culture normal rat renal tubular epithelial NRK-52E cells, showed that high concentrations of NaCl significantly inhibited the cell viability and increased the cell apoptosis. High concentration of NaCl reduce bone mineral density (BMD), as demonstrated by the significantly increased mRNA and protein levels of NCC and osteopontin (OPN), but decreased the levels of CLC-5, BMP-7, and 1α-hydroxylase. In addition, we found that ovariectomized (OVX) rats on a high-salt diet for 12 weeks had altered levels of these indices in the renal cortices. Moreover, the BMD in fourth and fifth lumbar vertebra (LV4 and 5) and femurs were significantly decreased and bone microstructure was destroyed of these rats. We also demonstrated that high concentration of NaCl enhanced the inhibition of these cytokines which is beneficial to increase BMD, induced by modulating ion channels NCC and CLC-5. In conclusion, our results indicate that high concentration of NaCl reduce BMD by regulating ion channels NCC and CLC-5.

MiR-210-3p inhibits osteogenic differentiation and promotes adipogenic differentiation correlated with Wnt signaling in ERα-deficient rBMSCs.

MicroRNAs (miRNAs) regulate activities in living organisms through various signaling pathways and play important roles in the development and progression of osteoporosis. The balance between osteogenic and adipogenic differentiation of rBMSCs is closely related to the occurrence of osteoporosis. ERα regulates bone metabolism in various tissues. However, the correlation among ERα, miRNAs, and the differentiation of rBMSCs is still unclear. In this study, we used lentivirus transfection into rBMSCs to construct an ERα-deficient model, analyzed the differences in expressed miRNAs between control and ERα-deficient rBMSCs. The results revealed that the expression of 25 miRNAs were upregulated, 164 miRNAs were downregulated, and some of the regulated miRNAs such as miR-210-3p and miR-214-3p were related to osteogenic or adipogenic differentiation, as well as to particular signaling pathways. Next, we overexpressed miR-210-3p to evaluate its effects on the osteogenic and adipogenic differentiation of rBMSCs, and identified the relationship among miR-210-3p, Wnt signaling pathway, and the differentiation of rBMSCs. The results indicated that ERα-deficient inhibited osteogenic differentiation, promoted adipogenic differentiation, and regulated the expression of some miRNAs. Meanwhile, overexpression of miR-210-3p promoted osteogenic differentiation and inhibited adipogenic differentiation of rBMSCs, processes likely to be related to the Wnt signaling pathway. In conclusion, we identified a group of upregulated and downregulated miRNAs in ERα-deficient rBMSCs that might play a vital role in regulating osteogenic or adipogenic differentiation. One of these, miR-210-3p, inhibited osteogenic differentiation and promoted adipogenic differentiation correlated with the Wnt signaling pathway in ERα-deficient rBMSCs, providing new insight into the regulation of bone metabolism.

Changes in related circular RNAs following ERß knockdown and the relationship to rBMSC osteogenesis.

Recently, several studies have indicated that circular RNAs (circRNAs) play significant roles in various disease; however, little is known about the chronology of estrogen receptor beta (ERß) deficiency and altered circRNA expression, or their relationship with osteogenesis. Herein, we show through western-blot and quantitative real-time PCR assays, that when ERß is silenced, the expression of osteogenesis-related proteins and mRNAs were down-regulated. We then performed RNA-Seq to analyze differential circRNA expression between the control and ERß knockdown group. This analysis revealed that, 146 circRNAs were differentially expressed by fold-change≥2.0, p ≤ 0.05, and, among this group, 68 circRNAs were down-regulated, while 78 were up-regulated. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and PANTHER pathway analyses were performed to predict the function of these differentially expressed circRNAs. Finally, co-expressed targets gene, and circRNA-microRNA network were constructed for predicted miRNA sponges. This research suggested that ERß may through 2:27713879|27755789/2:240822115|240867796-miR-328-5p-mRNA axis to regulate osteogenic differentiation.

Correction and Removal of Expression of Concern: Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates.

[This corrects the article DOI: 10.1039/C9RA06827A.].

[Chemical constituents and their antitumor cytotoxic activity in leaves of Ilex centrochinensis].

OBJECTIVE: To investigate the chemical constituents in leaves of Ilex centrochinensis and their antitumor bioactivity. METHOD: Various chromatography techniques such as column chromatography on silica gel, Sephadex LH-20 and preparative HPLC were used to isolate and purify the compounds and their structures were identified by spectral data and physicochemical properties. Their antitumor effect was tested by MTT method. RESULT: Ten compounds were isolated and identified as 1,4-benzenediol (1), (2S)-5,4'-dihydroxy-7,3'-dimethoxyflavan(2), (2S)-5,4'-dihydroxy-7-methoxyflavan (3), kaempferol (4), quercetin (5), naringenin (6), ursolic acid (7), uvaol (8), oleanolic acid (9) and beta-sitosterols (10). CONCLUSION: Compounds 1-5, 7, 8 were isolated from the species for the first time, among which compounds 1-3 were isolated from the Ilex genus for the first time. Compounds 2 and 3 showed strong cytotoxic activity against Huh7 cell lines with IC50 values of 8.98, 13.04 mg x L(-1), respectively. Compounds 7-9 exhibited weak cytotoxic activity against Caco-2 cell lines with IC50 values of 28.52, 38.28, 33.04 mg x L(-1), respectively.

Expression of concern: Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates.

Expression of concern for 'Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates' by Kehuan Sun et al., RSC Adv., 2019, 9, 32017-32020, https://doi.org/10.1039/C9RA06827A.

Antidepressant-Like Effects of Chaihu Shugan Powder () on Rats Exposed to Chronic Unpredictable Mild Stress through Inhibition of Endoplasmic Reticulum Stress-Induced Apoptosis.

OBJECTIVE: To investigate the antidepressant-like effects of Chaihu Shugan Powder (CSP, ) and to explore its underlying mechanisms. METHODS: Thirty-two Sprague-Dawley rats were randomly divided into control (CON), chronic unpredictable mild stress (CUMS), fluoxetine (FLU), and CSP groups, 8 rats in each group. All of the rats except for those in the control group were subjected to 3 consecutive weeks of CUMS to establish the depression model. The open field test (OFT), forced swimming test (FST), and sucrose preference test were used to assess the anti-anxiety and antidepressant effects of CSP. Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling was used to determine the apoptosis rate in the hippocampal tissues. The mRNA and protein levels of glucose-regulated protein (GRP) 78, spliced X-box-binding protein (XBP)-1, CCAAT/enhancer-binding protein homologous protein (CHOP), caspase-12, and c-Jun N-terminal kinase (JNK) in the hippocampus of rats were evaluated by real-time PCR and Western blot analysis, respectively. RESULTS: Administration of CSP alleviated anxiety and depression-like behavior in CUMS rats, as revealed by enhanced time and distance in the center of the OFT (P<0.05), an increased preference for sucrose, and longer swimming time and shorter immobility time during the FST (all P<0.05). In addition, CSP treatment significantly reduced the rate of apoptosis in rat hippocampal neurons (P<0.05). The mRNA and protein expression levels of GRP78, spliced XBP-1, and CHOP were down-regulated along with the expression of caspase-12 and cleaved caspase-12 proteins (all P<0.05), whereas total and phosphorylated JNK1 protein levels did not differ significantly between control and CSP-treated rats. CONCLUSION: CSP can improve depression-like behavior in rats exposed to CUMS, possibly by suppressing CHOP and caspase-12 mediated apoptosis in the rat hippocampus.

Highly efficient synthesis and monoamine oxidase B inhibitory profile of demethyleneberberine, columbamine and palmatine.

The biosynthesis of berberine alkaloids is thought to begin with the demethylation of berberine followed by methylation reactions to generate other type berberine alkaloids. This seemingly expeditious way to access berberine alkaloids has been stagnated for over half a century due to certain vexing synthetic problems, such as low isolated yield, complex operations and toxic reagents. We further investigated this bioinspired semi-synthesis strategy and significantly improved the synthetic efficacy, by providing a practical synthetic process for demethyleneberberine (DMB), columbamine and palmatine. Furthermore, we found that DMB (IC50, 9.06 µM) inhibited the activity of monoamine oxidase B (MAO-B), an enzyme that deaminates dopamine and is particularly involved in the pathology of Parkinson's disease. Besides, columbamine was able to decrease MAO-B activity by approximately 40%. These findings provide perquisites for further in vivo investigation to confirm the therapeutic potentiality of berberine alkaloids, DMB in particular.

Effectiveness associated with different therapies for senile osteoporosis: a network Meta-analysis.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of Chinese herbal medicines for invigorating the kidney (CHMIK) on senile osteoporosis. METHODS: We searched for studies in English-language databases (PubMed, the Cochrane Library, and Web of Science) and Chinese-language databases (China National Knowledge Infrastructure, Wan Fang Data, VIP Chinese periodical service platform, and China Biology Medicine disc from their inception to September 2017. Randomized controlled trials comparing the effectiveness of Traditional Chinese Medicine therapies (alone or in combination) and conventional clinical medicine therapies among older adult patients with osteoporosis were identified. We conducted a network Meta-analysis with a Bayesian hierarchical random-effects model using RStudio software, Version 3.4.1. RESULTS: Forty-three randomized controlled trials assessing the differences between Traditional Chinese Medicine and conventional clinical medicine were identified, including 15 treatments and involving 3316 patients. The results of the network Meta-analysis indicated that alendronate (odds ratio [OR] = 0.20, 95% confidence interval [CI]: 0.047-0.73) and calcium (OR = 0.18, 95% CI: 0.11-0.30) are significantly more effective if combined with oral CHMIK. CHMIK alone is significantly more effective than both alendronate (OR = 0.34, 95% CI: 0.10-1.0) and calcium (OR = 0.13, 95% CI: 0.056-0.28). Moreover, CHMIK + tuina + calcium is more effective than CHMIK + calcium + vitamin D + alendronate (OR = 18.0, 95% CI: 1.1-2.7e + 02). CONCLUSION: The present network Meta-analysis found that alendronate and calcium are more effective if combined with oral CHMIK and that oral CHMIK alone may be more effective than alendronate or calcium. Tuina may have an advantage over oral medicines. Oral CHMIK and calcitonin show the most potential for treating senile osteoporosis.

Highly stereoselective gram scale synthesis of all the four diastereoisomers of Boc-protected 4-methylproline carboxylates.

A general and practical synthetic process for all the four diastereoisomers of Boc-protected 4-methylproline carboxylates has been developed with essentially complete stereoselectivity on the gram scale, which represents the most diastereoselective preparation of 4-methylproline derivatives to date. This synthesis features an Evans asymmetric alkylation to elegantly establish the challenging stereochemistry of the 4-methyl group, providing valuable insights for the diastereoselective preparation of 4-substituted prolines.

iTRAQ-based proteomics reveals SOD2 as a potential salivary biomarker in liver cancer.

BACKGROUND: Salivary proteomic analysis has been extensively used in a wide range of cancer, but not in hepatocellular carcinoma. The aim of this study was to identify potential salivary biomarkers for hepatocellular carcinoma clinical screening. METHODS: In this study, we performed isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics analysis to detect differentially expressed proteins between saliva samples from 15 hepatocellular carcinoma patients and 15 healthy controls. Enzyme-linked immunosorbent assay (ELISA) verification was undertaken in saliva samples from 14 hepatocellular carcinoma patients and 14 healthy controls. RESULTS: Overall, 133 proteins with significant differential expression level (ratio > 1.5 or < 0.67) were detected. Using bioinformatic analysis, two candidate proteins were selected and subsequently verified by ELISA. The increased expression of superoxide dismutase 2, mitochondrial (SOD2) in hepatocellular carcinoma patients was confirmed by ELISA, with an area under the curve value of 0.9082. CONCLUSIONS: iTRAQ-based quantitative proteomics revealed that SOD2 might serve as a potential salivary biomarker for hepatocellular carcinoma detection. Our results indicated that a noninvasive and inexpensive salivary test might be established for hepatocellular carcinoma detection.

Lead exposure inhibits osteoblastic differentiation and inactivates the canonical Wnt signal and recovery by icaritin in MC3T3-E1 subclone 14 cells.

Exposure to lead (Pb) poses a threat to human bone health, including changes in bone mineral composition and the inhibition of skeletal growth and bone maturation. However, little is known about how Pb directly affects osteoblasts. In this work, we found that sub-toxic Pb concentrations suppressed bone nodule formation and inhibited differentiation in MC3T3-E1 subclone 14 cells, as shown by decreased expression levels of the differentiation markers alkaline phosphatase (ALP), type 1 collagen (COL1), osteocalcin (OC), and runt-related transcription factor 2 (RUNX2). Moreover, Pb inactivated the canonical Wnt pathway by regulating key components, such as Wnt3a, Dkk-1, pGSK3ß, and ß-catenin. Icaritin (ICT), a hydrolytic product of icariin from the genus Epimedium, attenuates the inhibitory effect of Pb on osteoblastic differentiation, as well as activate the canonical Wnt signal pathway. Taken together, the results suggest ICT as a potential bone protectant that may be used to prevent bone damage caused by Pb and can activate the canonical Wnt signal pathway.

Icariin stimulates osteogenic differentiation and suppresses adipogenic differentiation of rBMSCs via estrogen receptor signaling.

Icariin (ICA) is a major active ingredient in Herba epimedii, which is commonly used as a Chinese herbal medicine for the treatment of osteoporosis. Previous studies have revealed that ICA exerted a protective effect against bone loss and increased bone regeneration; however, the association between ICA and estrogen receptor (ER) signaling remains unclear. The aim of the present study was to determine the effect of ICA on rat bone marrow stromal cells (rBMSCs). Cell Counting Kit­8 assays were conducted to measure proliferation, alkaline phosphatase (ALP) activity was evaluated to assess osteoblast differentiation, and reverse transcription­quantitative polymerase chain reaction as well as western blotting were performed to detect the expression of cellular and molecular markers of osteogenic or adipogenic differentiation. The results demonstrated that treatment of rBMSCs with 10­6 M ICA stimulated rBMSC proliferation and ALP activity. Furthermore, ICA treatment increased the expression of the osteogenic markers runt­related transcription factor 2, collagen type 1 and bone morphogenetic Protein 2; however, it also decreased the expression of the adipogenic differentiation markers peroxisome proliferator­activated receptor gamma and CCAAT/enhancer­binding protein α. Treatment of rBMSCs with ICI182780, an ER antagonist, blocked the effects of ICA. Taken together, these findings indicated that ICA may stimulate osteoblast differentiation and inhibit adipogenic differentiation via the activation of the ER signaling pathway. Therefore, ICA has the potential to serve as a therapeutic alternative for the prevention and treatment of osteoporosis.

Icaritin induces MC3T3-E1 subclone14 cell differentiation through estrogen receptor-mediated ERK1/2 and p38 signaling activation.

Icaritin (ICT), a hydrolytic product of icariin from the genus Epimedium, has many indicated pharmacological and biological activities. Several studies have shown that ICT has potential osteoprotective effects, including stimulation of osteoblast differentiation and inhibition of osteoclast differentiation. However, the molecular mechanism for this anabolic action of ICT remains largely unknown. Here, we found that ICT could enhance MC3T3-E1 subclone 14 preosteoblastic cell differentiation associated with increased mRNA levels and protein expression of the differentiation markers alkaline phosphatase (ALP), type 1 collagen (COL1), osteocalcin (OC), osteoponin (OPN) and runt-related transcription factor 2 (RUNX2), and improved mineralization, confirmed by bone nodule formation and collagen synthesis. To characterize the underlying mechanisms, we examined the effect of ICT on estrogen receptor (ER) and mitogen-activated protein kinase (MAPK) signaling. ICT treatment induced p38 kinase and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, but it demonstrated at the same time point no effect on activation of c-Jun N-terminal kinase (JNK). ER antagonist ICI182780, p38 antagonist SB203580 and ERK1/2 antagonist PD98059 markedly inhibited the ICT-induced the mRNA expression of ALP, COL1, OC and OPN. ICI182780 attenuated the ICT-induced phosphorylation of p38 and ERK1/2. These observations indicate a potential mechanism of osteogenic effects of ICT involving the ERK1/2 and p38 pathway activation through the ER.

Effect of Tiantai No.1 on gene expression profiles in hippocampus of Alzheimer's disease rats by bioinformatic analysis.

OBJECTIVE: To study the effect of Tiantai No. 1 [symbol in text] on gene expression profile in hippocampus of Alzheimer's disease (AD) rat, molecular genetic target points of the effect of this drug were defined, its molecular genetic pharmacodynamic mechanism of anti-AD was further explored at molecular gene level, and a scientific basis was provided for its clinical availability and promotion. METHODS: Thirty male Sprague-Dawley rats were divided into three groups with 10 rats per group: sham-operation group, model group and Tiantai No. 1 group. Sterile surgical procedure was applied, the model group with bilateral hippocampal injection of Aß1-40 was established, and normal saline was used instead of Aß1-40 in the sham-operation group. One week after the models was made, rats were administered by gastric lavage once every day for three consecutive weeks. The rats of the sham-operation group and the model group were daily fed with purified water by lavage; the rats of the Tiantai No.1 group treated group were administered with Tiantai No.1 by lavage. Total RNAs of hippocampus tissues were extracted with Trizol, the changes of hippocampus gene expression profiles in the above three groups were analyzed by using Affymetrix rat whole genome expression profile microarray. RESULTS: Microarray analysis showed that, compared with the sham-operation group, the hippocampus of the model group had 50 up-regulated genes with significant difference (fold change >2), and 21 down-regulated genes with significant difference (fold change <0.5); compared with the hippocampus of the model group, the hippocampus of the Tiantai No. 1 group was found to have 5 up-regulated genes with significant difference (fold change >2) and 20 down-regulated genes with significant difference (fold change <0.5). The functions of differentially expressed genes of the groups were involved in nervous system's development, neuronic differentiation and function-regulation, cellular growth and differentiation and apoptosis, synaptic occurrence and plasticity, inflammation and immune response, ion channels/transporters, cellular signal transduction, cellular material/energy metabolism and so on. CONCLUSION: Tiantai No. 1 can regulate hippocampal function, and further regulate the brain function of animals in multiple gene target points by a number of ways.

Analysis of hippocampal gene expression profile of Alzheimer's disease model rats using genome chip bioinformatics.

In this study, an Alzheimer's disease model was established in rats through stereotactic injection of condensed amyloid beta 1-40 into the bilateral hippocampus, and the changes of gene expression profile in the hippocampus of rat models and sham-operated rats were compared by genome expression profiling analysis. Results showed that the expression of 50 genes was significantly up-regulated (fold change ≥ 2), while 21 genes were significantly down-regulated in the hippocampus of Alzheimer's disease model rats (fold change ≤ 0.5) compared with the sham-operation group. The differentially expressed genes are involved in many functions, such as brain nerve system development, neuronal differentiation and functional regulation, cellular growth, differentiation and apoptosis, synaptogenesis and plasticity, inflammatory and immune responses, ion channels/transporters, signal transduction, cell material/energy metabolism. Our findings indicate that several genes were abnormally expressed in the metabolic and signal transduction pathways in the hippocampus of amyloid beta 1-40-induced rat model of Alzheimer's disease, thereby affecting the hippocampal and brain functions.