RNA-binding protein HuR regulates translation of vitamin D receptor modulating rapid epithelial restitution after wounding.

Homeostasis of the intestinal epithelium is tightly regulated by numerous extracellular and intracellular factors including vitamin D and the vitamin D receptor (VDR). VDR is highly expressed in the intestinal epithelium and is implicated in many aspects of gut mucosal pathophysiology, but the exact mechanism that controls VDR expression remains largely unknown. The RNA-binding protein human antigen R (HuR) regulates the stability and translation of target mRNAs and thus modulates various cellular processes and functions. Here we report a novel role of HuR in the posttranscriptional control of VDR expression in the intestinal epithelium. The levels of VDR in the intestinal mucosa decreased significantly in mice with ablated HuR, compared with control mice. HuR silencing in cultured intestinal epithelial cells (IECs) also reduced VDR levels, whereas HuR overexpression increased VDR abundance; neither intervention changed cellular Vdr mRNA content. Mechanistically, HuR bound to Vdr mRNA via its 3'-untranslated region (UTR) and enhanced VDR translation in IECs. Moreover, VDR silencing not only inhibited IEC migration over the wounded area in control cells but also prevented the increased migration in cells overexpressing HuR, although it did not alter IEC proliferation in vitro and growth of intestinal organoids ex vivo. The human intestinal mucosa from patients with inflammatory bowel diseases exhibited decreased levels of both HuR and VDR. These results indicate that HuR enhances VDR translation by directly interacting with its mRNA via 3'-UTR and that induced VDR by HuR is crucial for rapid intestinal epithelial restitution after wounding.

RNA-Binding Protein HuR Regulates Paneth Cell Function by Altering Membrane Localization of TLR2 via Post-transcriptional Control of CNPY3.

BACKGROUND & AIMS: Paneth cells secrete antimicrobial proteins including lysozyme via secretory autophagy as part of the mucosal protective response. The ELAV like RNA-binding protein 1 (ELAVL1, also called HuR) regulates stability and translation of messenger RNAs (mRNAs) and many aspects of mucosal physiology. We studied the posttranscriptional mechanisms by which HuR regulates Paneth cell function. METHODS: Intestinal mucosal tissues were collected from mice with intestinal epithelium (IE)-specific disruption of HuR (IE-HuR-/-), HuRfl/fl-Cre- mice (controls), and patients with inflammatory bowel diseases and analyzed by histology and immunohistochemistry. Paneth cell functions were determined by lysozyme-immunostaining assays. We isolated primary enterocytes from IE-HuR-/- and control mice and derived intestinal organoids. HuR and the chaperone CNPY3 were overexpressed from transgenes in intestinal epithelial cells (IECs) or knocked down with small interfering RNAs. We performed RNA pulldown assays to investigate interactions between HuR and its target mRNAs. RESULTS: Intestinal tissues from IE-HuR-/- mice had reduced numbers of Paneth cells, and Paneth cells had fewer lysozyme granules per cell, compared with tissues from control mice, but there were no effects on Goblet cells or enterocytes. Intestinal mucosa from patients with inflammatory bowel diseases had reduced levels of HuR and fewer Paneth cells. IE-HuR-/- mice did not have the apical distribution of TLR2 in the intestinal mucosa as observed in control mice. IECs from IE-HuR-/- mice expressed lower levels of CNPY3. Intestinal organoids from IE-HuR-/- mice were smaller and contained fewer buds compared with those generated from controls, and had fewer lysozyme-positive cells. In IECs, knockdown of HuR decreased levels of the autophagy proteins LC3-I and LC3-II, compared with control cells, and prevented rapamycin-induced autophagy. We found HuR to interact directly with the Cnpy3 mRNA coding region and increase levels of CNPY3 by increasing the stability and translation of Cnpy3 mRNA. CNPY3 bound TLR2, and cells with knockdown of CNPY3 or HuR lost membrane localization of TLR2, but increased cytoplasmic levels of TLR2. CONCLUSIONS: In studies of mice, IECs, and human tissues, we found HuR to increase expression of CNPY3 at the posttranscriptional level. CNPY3 is required for membrane localization of TLR2 and Paneth cell function.

Cajanolactone A from Cajanus cajan Promoted Osteoblast Differentiation in Human Bone Marrow Mesenchymal Stem Cells via Stimulating Wnt/LRP5/ß-Catenin Signaling.

Cajanolactone A (CLA) is a stilbenoid discovered by us from Cajanus cajan (L.) Millsp. In our study, CLA was found to promote osteoblast differentiation in human bone marrow mesenchymal stem cells (hBMSCs), as judged by increased cellular alkaline phosphatase activity and extracellular calcium deposits, and elevated protein expression of Runx2, collagen-1, bone morphogenetic protein-2, and osteopontin. Mechanistic studies revealed that hBMSCs undergoing osteoblast differentiation expressed upregulated mRNA levels of Wnt3a, Wnt10b, LRP5/6, Frizzled 4, ß-catenin, Runx2, and Osterix from the early stage of differentiation, indicating the role of activated Wnt/ß-catenin signaling pathway in osteoblast differentiation. Addition of CLA to the differentiation medium further increased the mRNA level of Wnt3a, Wnt10b, Frizzled 4, LRP5, and ß-catenin, inferring that CLA worked by stimulating Wnt/LRP5/ß-catenin signaling. Wnt inhibitor dickkopf-1 antagonized CLA-promoted osteoblastogenesis, indicating that CLA did not target the downstream of canonical Wnt signaling pathway. Treatment with CLA caused no changes in mRNA expression level, as well as protein secretion of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL), indicating that CLA did not affect the OPG/RANKL axis. Our results showed that CLA, which promoted osteoblast differentiation in hBMSCs, through activating Wnt/LRP5/ß-catenin signaling transduction, is a promising anti-osteoporotic drug candidate.

Acute and sub-chronic toxicity of Cajanus cajan leaf extracts.

CONTEXT: The leaves of Cajanus cajan (L.) Millsp. (Fabaceae) have diverse bioactivities, but little safety data are reported. OBJECTIVE: This study examines the toxicological profiles of C. cajan leaf extracts. MATERIALS AND METHODS: The leaves were extracted by water or 90% ethanol to obtain water or ethanol extract (WEC or EEC). EEC was suspended in water and successively fractionated into dichloroform and n-butanol extracts (DEC and BEC). Marker compounds of the extracts were monitored by high-performance liquid chromatography (HPLC). Kunming mice were administered with a single maximum acceptable oral dose (15.0 g/kg for WEC, EEC and BEC and 11.3 g/kg for DEC) to determine death rate or maximal tolerated doses (MTDs). In sub-chronic toxicity investigation, Sprague-Dawley rats were orally given WEC or EEC at 1.5, 3.0 or 6.0 g/kg doses for four weeks and observed for two weeks after dosing to determine toxicological symptoms, histopathology, biochemistry and haematology. RESULTS: Flavonoids and stilbenes in the extracts were assayed. In acute toxicity test, no mortality and noted alterations in weight and behavioural abnormality were observed, and the maximum oral doses were estimated as MTDs. In sub-chronic toxicity study, no mortality and significant variances in haematological and biochemical parameters or organ histopathology were observed, but increased kidney weight in 3.0 g/kg WEC- or 3.0 and 6.0 g/kg EEC-treated female rats, and reduced testes and epididymis weight in EEC-treated male rats were recorded. These changes returned to the level of control after recovery period. CONCLUSION: Acute and sub-chronic toxicity of Cajanus cajan leaf extracts was not observed.

[Chemical Constituents from Periploca forrestii].

Objective: To study the chemical constituents from Periploca forrestii. Methods: The constituents were separated by column chromatography and their structures were elucidated by spectroscopic methods. Results: Seven compounds were isolated from Periploca forrestii and identified as wogonin( 1),negletein( 2),vanilline( 3),isovanilline( 4),periplocoside L( 5),ß-sitosterol( 6) and ß-daucosterol( 7). Conclusion: Compounds 1 and 2 are obtained from this genus for the first time,and compounds 3 ~ 5 are isolated from this plant for the first time.

[Effect of Sijunzi Decoction Polysaccharide on IEC-6 Cell Migration,Potassium Channel and Membrane Potential].

Objective: To investigate the effect of Sijunzi decoction polysaccharide( SJZDP) on intestinal epithelial cells( IEC-6)cell migration and polyamine signaling pathway potassium channel during intestinal epithelial cell migration, and to explore the mechanism of SJZDP on promoting gastrointestinal mucosal restitution after wounding. Methods: Cell migration model was established by scratch damage, and then the effect of SJZDP normal cultured or with difluoromethylornithine( DFMO) and 4-aminopyridine( 4-AP) on IEC-6 cell migration was observed and calculated on this wounding model. The effect of SJZDP on expression of IEC-6 cell kv1. 1 mRNA and protein levels were detected by RT-q PCR and Western blot analysis, respectively. The Effects of SJZDP on IEC-6 cell membrane potential were detected by flow cytometry. Results: The results showed that treatment with SJZDP( 40,80,160 mg / L) caused a promotion of IEC-6 cell migration,and increased of expression of in IEC-6 cell kv1. 1 mRNA and protein significantly( P < 0. 05 or P < 0. 01) compared with normal control group. In addition, SJZDP( 40,80,160 mg / L) increased cell membrane potential which resulted in cell membrane hyperpolarization compared with normal control group( P < 0. 05 or P < 0. 01). SJZDP( 40,80,160 mg / L) reversed the inhibition of cell migration was reduced,kv1. 1 mRNA,kv1. 1 protein expression, and cell membrane potential were decreased by polyamines synthesis inhibitor DFMO compared with DFMO model group( P < 0. 05 or P < 0. 01). SJZDP( 20,40,80 mg / L) reversed the inhibition of cell migration,kv1. 1 protein and mRNA levels expression were decreased by potassium channel inhibitor 4-AP compared with 4-AP model group( P < 0. 05 or P < 0. 01). Conclusion: These results indicate that the effect of SJZDP on promoting IEC-6 cell migration may be related to its influence on polyamine signaling pathway potassium channel and cell membrane potential.

A Halogen-Containing Stilbene Derivative from the Leaves of Cajanus cajan that Induces Osteogenic Differentiation of Human Mesenchymal Stem Cells.

A new natural halogen-containing stilbene derivative was isolated from the leaves of Cajanus cajan (L.) Millsp. and identified as 3-O-(3-chloro-2-hydroxyl-propanyl)-longistylin A by comprehensive spectroscopic and chemical analysis, and named cajanstilbene H (1). It is the first halogen-containing stilbene derivative found from plants. In human mesenchymal stem cells (hMSC) from bone marrow, 1 did not promote cell proliferation, but distinctly enhanced osteogenic differentiation of hMSC in time- and dose-dependent manners. In six human cancer cell lines, 1 showed a moderate inhibitory effect on cell proliferation, with IC50 values of 21.42-25.85 µmol·L(-1).

Sinomenine inhibits macrophage M1 polarization by downregulating α7nAChR via a feedback pathway of α7nAChR/ERK/Egr-1.

BACKGROUND: Sinomenine (SIN) is an anti-inflammatory drug that has been used for decades in China to treat arthritis. In a previous study, SIN acted on α7 nicotinic acetylcholine receptor (α7nAChR) to inhibit inflammatory responses in macrophages, which indicates a new anti-inflammatory mechanism of SIN. However, the level of α7nAChR was increased in the inflammatory responses and was downregulated by SIN in vitro, so the underlying mechanisms of SIN acting on α7nAChR remain unclear. PURPOSE: To analyze the role of α7nAChR in inflammation and the effect and mechanism of SIN regulation of α7nAChR. METHODS: The effects of SIN on α7nAChR in endotoxemic mice and LPS-stimulated macrophages were observed. Nicotine (Nic) was used as a positive control, and berberine (Ber) was used as a negative control targeting α7nAChR. The antagonists of α7nAChR, α-bungarotoxin (BTX) and mecamylamine (Me), were used to block α7nAChR. In RAW264.7 macrophage cells in vitro, α7nAChR short hairpin RNA (shRNA) was used to knock down α7nAChR. Macrophage polarization was analyzed by the detection of TNF-α, IL-6, iNOS, IL-10, Arg-1, and Fizz1. U0126 was used to block ERK phosphorylation. The cytokines α7nAChR, ERK1/2, p-ERK1/2 and Egr-1 were detected. RESULTS: SIN decreased the levels of TNF-α, IL-6 and the expression of α7nAChR increased by LPS in endotoxemic mice. The above effects of SIN were attenuated by BTX. In the α7nAChR shRNA transfected RAW264.7 cells, compared with the control, α7nAChR was knocked down, and M1 phenotype markers (including TNF-α, IL-6, and iNOS) were significantly downregulated, whereas M2 phenotype markers (including IL-10, Arg-1, and Fizz1) were significantly upregulated when stimulated by LPS. SIN inhibited the expression of p-ERK1/2 and the transcription factor Egr-1 induced by LPS in RAW264.7 cells, and the above effects of SIN were attenuated by BTX. The expression of α7nAChR was suppressed by U0126, which lessened the expression of p-ERK1/2 and Egr-1. CONCLUSIONS: SIN acts on α7nAChR to inhibit inflammatory responses and downregulates high expression of α7nAChR in vivo and in vitro. The increase of α7nAChR expression is correlated with inflammatory responses and participates in macrophage M1 polarization. SIN downregulates α7nAChR via a feedback pathway of α7nAChR/ERK/Egr-1, which contributes to inhibiting macrophage M1 polarization and inflammatory responses.

The Short Health Scale: A Valid and Reliable Quality-of-Life Scale for Mainland Chinese Patients with Inflammatory Bowel Disease.

Background: The aim of our study was to translate and validate the mainland Chinese version of the short health scale (SHS), a disease-specific quality-of-life (QoL) scale for patients with inflammatory bowel disease (IBD). Methods: The SHS was translated and validated according to the standard process: a translation and back-translation procedure and a reliability and validation study. Patients with IBD were enrolled, and their QoL was assessed using the SHS, the short inflammatory bowel disease questionnaire (SIBDQ), and the Bristol stool form scale. Reliability (internal consistency reliability, split-half reliability, and test-retest reliability) and validity analyses were performed to evaluate the psychometric characteristics of the SHS. The impacts of different severity of major symptoms on QoL were analyzed by comparing the scores of SHS. Results: A total of 112 patients with IBD (69 with ulcerative colitis and 43 with Crohn's disease) completed the mainland Chinese version of the SHS, and 34 patients completed the SHS a second time within one to two weeks. Cronbach's alpha value of the SHS was 0.90, and its split-half coefficient was 0.83. Intraclass correlation coefficients of the four items ranged from 0.52 to 0.72. All four items of the SHS were significantly associated with the corresponding domains of the SIBDQ, with correlation coefficients ranging from -0.52 to -0.69 (p < 0.001). The results of confirmatory factor analysis indicated a good fit of the one-factor model, with comparative fit index (CFI) = 0.878, normed fit index (NFI) = 0.874, incremental fit index (IFI) = 0.880, and goodness of fit index (GFI) = 0.842. The patients with severe symptoms had higher scores in the SHS than those with no or mild symptoms. Conclusions: The SHS was simple and quick to be used. The SHS had good validity and reliability and was suitable for evaluating the QoL of patients with IBD in mainland China.

Musashi 1-positive cells derived from mouse embryonic stem cells treated with LY294002 are prone to differentiate into intestinal epithelial-like tissues.

The majority of Musashi 1 (Msi1)­positive cells derived from mouse embryonic stem cells (mESCs) are prone to differentiate into neural epithelial­like cells, and only a small proportion of Msi1­positive cells differentiate into intestinal epithelial­like cells. Whether inhibiting the phosphatidylinositol 3­kinase (PI3K) signaling of mESCs can promote the differentiation of Msi1­positive cells into intestinal epithelial­like cells remains to be fully elucidated. In the present study, to inhibit PI3K signaling, mESCs were treated with LY294002. A pMsi1­green fluorescence protein reporter plasmid was used to sort the Msi1­positive cells from mESCs treated and untreated with LY294002 (5 µmol/l). The Msi1­positive cells were hypodermically engrafted into the backs of non­obese diabetic/severe combined immunodeficient mice. The presence of neural and intestinal epithelial­like cells in the grafts was detected by reverse transcription­quantitative polymerase chain reaction analysis and immunohistochemistry. Compared with the Msi1­positive cells derived from mESCs without LY294002 treatment, Msi1­positive cells derived from mESCs treated with LY294002 expressed higher levels of leucine­rich repeat­containing G­protein coupled receptor, a marker of intestinal epithelial stem cells, and lower levels of Nestin, a marker of neural epithelial stem cells. The grafts from Msi1­positive cells treated with LY294002 contained more intestinal epithelial­like tissues and fewer neural epithelial­like tissues, compared with those from untreated Msi1­positive cells. LY294002 had the ability to promote the differentiation of mESCs into intestinal epithelial­like tissues. The Msi1­positive cells selected from the cell population derived from mESCs treated with LY294002 exhibited more characteristics of intestinal epithelial stem cells than those from the untreated group.

Polysaccharide extracts of Astragalus membranaceus and Atractylodes macrocephala promote intestinal epithelial cell migration by activating the polyamine-mediated K+ channel.

Astragalus membranaceus (Radix Astragali, RA) and Atractylodes macrocephala (Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of polysaccharides extracts from these two herbs on IEC-6 cell migration and explored the potential underlying mechanisms. A migration model with IEC-6 cells was induced using a single-edged razor blade along the diameter of cell layers in six-well polystyrene plates. The cells were grown in control media or media containing spermidine (5 µmol·L-1, SPD), alpha-difluoromethylornithine (2.5 mmol·L-1, DFMO), 4-Aminopyridine (40 µmol·L-1, 4-AP), the polysaccharide extracts of RA or RAM (50, 100, or 200 mg·L-1), DFMO plus SPD, or DFMO plus polysaccharide extracts of RA or RAM for 12 or 24 h. Next, cytosolic free Ca2+ ([Ca2+]cyt) was measured using laser confocal microscopy, and cellular polyamine content was quantified with HPLC. Kv1.1 mRNA expression was assessed using RT-qPCR and Kv1.1 and RhoA protein expressions were measured with Western blotting analysis. A cell migration assay was carried out using Image-Pro Plus software. In addition, GC-MS was introduced to analyze the monosaccharide composition of both polysaccharide extracts. The resutls showed that treatment with polysaccharide extracts of RA or RAM significantly increased cellular polyamine content, elevated [Ca2+]cyt and accelerated migration of IEC-6 cells, compared with the controls (P < 0.01). Polysaccharide extracts not only reversed the inhibitory effects of DFMO on cellular polyamine content and [Ca2+]cyt, but also restored IEC-6 cell migration to control level (P < 0.01 or < 0.05). Kv1.1 mRNA and protein expressions were increased (P < 0.05) after polysaccharide extract treatment in polyamine-deficient IEC-6 cells and RhoA protein expression was increased. Molar ratios of D-ribose, D-arabinose, L-rhamnose, D-mannose, D-glucose, and D-galactose was 1.0 : 14.1 : 0.3 : 19.9 : 181.3 : 6.3 in RA and 1.0 : 4.3 : 0.1 : 5.7 : 2.8 : 2.2 in RAM. In conclusion, treatment with RA and RAM polysaccharide extracts stimulated migration of intestinal epithelial cells via a polyamine-Kv1.1 channel activated signaling pathway, which facilitated intestinal injury healing.

[Phytochemical investigation on Lysimachia fortunei].

OBJECTIVE: To investigate the chemical constituents in the ethyl acerate extract of Lysimachia fortunei. METHOD: The compounds were isolated by silica gel chromatography, and their structures were elucidated by NMR data and references. RESULT: Nine natural constituents were isolated, and their structures were identified as 9, 19-cyclolanost-24-en-3-one (1), 24-ethyl-5alpha-cholesta-7, 22(E)-dien-3-one (2), 1-pentatriacontanol (3), beta-stigmasterol (4), 24-ethyl-5alpha-cholesta-7, 22(E)-dien-3beta-ol (5), palmitic acid (6), isorhamnetin (7), kaempferol (8) and quercetin (9) respectively. CONCLUSION: All compounds mentioned above were isolated from this plant for the first time, and compound 1, 2 and 5 were obtained from the genus for the first time.

Atractylodes macrocephala Koidz promotes intestinal epithelial restitution via the polyamine--voltage-gated K+ channel pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Atractylodes macrocephala Koidz (AMK) has been used widely as a digestive and tonic in traditional Chinese medicine. AMK has shown noteworthy promoting effect on intestinal epithelial cell migration, which might represent a promising candidate for the treatment of intestinal mucosa injury. The aim of this study was to investigate the efficacy of AMK on intestinal mucosal restitution and the underlying mechanisms via IEC-6 cell migration model. MATERIALS AND METHODS: A wounding model of IEC-6 cells was induced by a single-edge razor blade along the diameter of six-well polystyrene plates. The cells were grown in control cultures and in cultures containing spermidine (5 µmol/L, SPD, reference drug), alpha-difluoromethylornithine (2.5 mmol/L, DFMO, polyamine inhibitor), AMK (50, 100, and 200 µg/mL), DFMO plus SPD and DFMO plus AMK for 24h. The membrane potential (MP) and cytosolic free Ca(2+) concentration ([Ca(2+)]cyt) were detected by flow cytometry, and polyamines content was determined via high-performance liquid chromatography (HPLC). The expression of Kv1.1 mRNA and protein levels were assessed by RT-qPCR and Western blot analysis, respectively. Cell migration assay was carried out using the Image-Pro Plus software. All of these indexes were used to evaluate the effectiveness of AMK. RESULTS: (1) Treatment with AMK caused significant increases in cellular polyamines content, membrane hyperpolarization, an elevation of [Ca(2+)]cyt and an acceleration of cell migration in IEC-6 cells, as compared to control group. (2) AMK not only reversed the inhibitory effects of DFMO on the polyamines content, MP, and [Ca(2+)]cyt but also restored IEC-6 cell migration to control levels. (3) The Kv1.1 mRNA and protein expression were significantly increased by AMK treatment in control and polyamine-deficient IEC-6 cells. CONCLUSIONS: The results of our current studies revealed that treatment with AMK significantly stimulates the migration of intestinal epithelial cells through polyamine-Kv1.1 channel signaling pathway, which could promote the healing of intestinal injury. These results suggest the potential usefulness of AMK to cure intestinal disorders characterized by injury and ineffective repair of the intestinal mucosa.