N(6)-methyladenosine RNA methyltransferase like 3 inhibits extracellular matrix synthesis of endplate chondrocytes by downregulating sex-determining region Y-Box transcription factor 9 expression under tension

OBJECTIVE

Tension stimulation is an important inducer of endplate cartilage degeneration, but the specific regulatory mechanism remains unclear. This study was the first to reveal the mechanism by which methyltransferase-like 3 (METTL3)-mediated N(6)-methyladenosine (m6A) modification affected the extracellular matrix anabolism by tension-induced endplate chondrocytes.

METHOD

We examined the differences in METTL3 expression and m6A methylation levels in human endplate chondrocytes and human cartilage endplate tissues under in vitro tension. The effect on endplate cartilage degeneration was evaluated by manipulating m6A methylation mediated by METTL3 in vivo and in vitro. The effect of METTL3-mediated m6A methylation on the stability of sex-determining region Y-box transcription factor 9 (SOX9) gene expression was determined experimentally.

RESULTS

METTL3 expression and m6A methylation levels were significantly increased in degenerative human endplate cartilage tissue. Similarly, tension stimulation inhibited the ability of human endplate chondrocytes to synthesize extracellular matrix, which was accompanied by an increase in METTL3-mediated m6A methylation. The ability of endplate chondrocytes to resist tension was significantly enhanced by inhibiting METTL3 expression and subsequently downregulating m6A methylation in vitro and in vivo, thereby reducing intervertebral disc degeneration. Furthermore, METTL3 mediated SOX9 RNA methylation and disrupted SOX9 mRNA stability, thereby inhibiting the gene expression of the downstream collagen type II alpha 1 chain.

CONCLUSION

Tension stimulation downregulated SOX9 expression through METTL3-mediated m6A methylation, thereby inhibiting the synthesis of extracellular matrix in endplate chondrocytes.

Identification of Dental Stem Cells Similar to Skeletal Stem Cells

Stem and progenitor cells play important roles in the development and maintenance of teeth and bone. Surface markers expressed in bone marrow–derived mesenchymal stem cells are also expressed in dental tissue–derived stem cells. Mouse skeletal stem cells (mSSCs, CD45−Ter119−Tie2−CD51+Thy−6C3−CD105−CD200+) and human skeletal stem cells (hSSCs, CD45−CD235a−TIE2−CD31−CD146−PDPN+CD73+CD164+) have been identified in bone and shown to play important roles in skeletal development and regeneration. However, it is unclear whether dental tissues also harbor mSSC or hSSC populations. Here, we employed rainbow tracers and found that clonal expansion occurred in mouse dental tissues similar to that in bone. We sorted the mSSC population from mouse periodontal ligament (mPDL) tissue and mouse dental pulp (mDP) tissue in the lower incisors by fluorescence-activated cell sorting (FACS). In addition, we demonstrated that mPDL-derived skeletal stem cells (mPDL-SSCs) and mDP-derived skeletal stem cells (mDP-SSCs) have similar clonogenic capacity, as well as cementogenic and odontogenic potential, but not adipogenic potential, similar to the characteristics of mSSCs. Moreover, we found that the dental tissue–derived mSSC population plays an important role in repairing clipped incisors. Importantly, we sorted the hSSC population from human periodontal ligament (hPDL) and human dental pulp (hDP) tissue in molars and identified its stem cell characteristics. Finally, hPDL-like and hDP-like structures were generated after transplanting hPDL-SSCs and hDP-SSCs beneath the renal capsules. In conclusion, we demonstrated that mouse and human PDL and DP tissues harbor dental stem cells similar to mSSCs and hSSCs, respectively, providing a precise stem cell population for the exploration of dental diseases.

Crystal structure of the plant feruloyl-coenzyme A monolignol transferase provides insights into the formation of monolignol ferulate conjugates

Lignin is a highly complex phenolic polymer which is essential for plants, but also makes it difficult for industrial processing. Engineering lignin by introducing relatively labile linkages into the lignin backbone can render it more amenable to chemical depolymerization. It has been reported that introducing a feruloyl-coenzyme A monolignol transferase from Angelica sinensis (AsFMT) into poplar could incorporate monolignol ferulate conjugates (ML-FAs) into lignin polymers, suggesting a promising way to manipulate plants for readily deconstructing. FMT catalyzes a reaction between monolignols and feruloyl-CoA to produce ML-FAs and free CoA-SH. However, the mechanisms of substrate specificity and catalytic process of FMT remains poorly understood. Here we report the structure of AsFMT, which adopts a typical fold of BAHD acyltransferase family. Structural comparisons with other BAHD homologs reveal several unique structural features of AsFMT, different from those of the BAHD homologs. Further molecular docking studies showed that T375 in AsFMT may function as an oxyanion hole to stabilize the reaction intermediate and also proposed a role of H278 in the binding of the nucleophilic hydroxyl group of monolignols. Together, this study provides important structural insights into the reactions catalyzed by AsFMT and will shed light on its future application in lignin engineering.

Measurement of the Cross Section for e^{+}e^{-}→Hadrons at Energies from 2.2324 to 3.6710 GeV

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.

The status and predictors of self-care among older adults with hypertension in China using the Chinese version of Self-Care of Hypertension Inventory - A cross-sectional study

AIM

To investigate the status and predictors of self-care among older adults with hypertension in China by the Chinese version of Self-Care of Hypertension Inventory.

DESIGN

A cross-sectional questionnaire survey.

METHODS

A convenience sampling of 544 older adults with hypertension was surveyed using the Chinese version of Self-Care of Hypertension Inventory. SPSS25.0 software was used for statistical analysis of the data. Generalized liner model univariate analysis and the optimal scaling regression analysis were performed to investigate the predictors of self-care.

RESULTS

The status of self-care was poor with the median and inter-quartile range of total scores of self-care (140.00 ± 67), the scores of self-care maintenance (50 ± 24.76), the scores of self-care management (56.25 ± 29.41) and the scores of self-care confidence (54.79 ± 29.17). Age, family model, primary caregiver, maximum systolic blood pressure, coverage of medical insurance, disease duration, receiving self-care education, education level, economic burden and family history of hypertension were the most powerful predictors of self-care among older adults with hypertension.

Circulating miRNAs and Vascular Injury Markers Associate with Cardiovascular Function in Older Patients Reaching End-Stage Kidney Disease

The prevalence of end-stage kidney disease (ESKD) is rapidly increasing and mostly occurring in patients aged 65 years or older. The main cause of death in these patients is cardiovascular disease (CVD). Novel markers of vascular integrity may thus be of clinical value for identifying patients at high risk for CVD. Here we associated the levels of selected circulating angiogenic miRNAs, angiopoietin-2 (Ang-2) and asymmetric dimethylarginine (ADMA) with cardiovascular structure and function (as determined by cardiovascular MRI) in 67 older patients reaching ESKD that were included from ‘The Cognitive decline in Older Patients with End stage renal disease’ (COPE) prospective, multicentered cohort study. We first determined the association between the vascular injury markers and specific heart conditions and observed that ESKD patients with coronary heart disease have significantly higher levels of circulating ADMA and miR-27a. Moreover, circulating levels of miR-27a were higher in patients with atrial fibrillation. In addition, the circulating levels of the vascular injury markers were associated with measures of cardiovascular structure and function obtained from cardiovascular MRI: pulse wave velocity (PWV), ejection fraction (EF) and cardiac index (CI). We found Ang-2 and miR-27a to be strongly correlated to the PWV, while Ang-2 also associated with ejection fraction. Finally, we observed that in contrast to miR-27a, Ang-2 was not associated with a vascular cause of the primary kidney disease, suggesting Ang-2 may be an ESKD-specific marker of vascular injury. Taken together, among older patients with ESKD, aberrant levels of vascular injury markers (miR-27a, Ang-2 and ADMA) associated with impaired cardiovascular function. These markers may serve to identify individuals at higher risk of CVD, as well as give insight into the underlying (vascular) pathophysiology.

First Measurement of Polarizations in the Decay D^{0}→ωφ

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy sqrt[s]=3.773  GeV by the BESIII detector, the decay D^{0}→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10^{-4} with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D^{0}→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

Dual Mechanisms of Coniferyl Alcohol in Phenylpropanoid Pathway Regulation

Lignin is a complex phenolic polymer that imparts cell wall strength, facilitates water transport and functions as a physical barrier to pathogens in all vascular plants. Lignin biosynthesis is a carbon-consuming, non-reversible process, which requires tight regulation. Here, we report that a major monomer unit of the lignin polymer can function as a signal molecule to trigger proteolysis of the enzyme L-phenylalanine ammonia-lyase, the entry point into the lignin biosynthetic pathway, and feedback regulate the expression levels of lignin biosynthetic genes. These findings highlight the highly complex regulation of lignin biosynthesis and shed light on the biological importance of monolignols as signaling molecules.

Visible-light-initiated regio- and stereoselective C(sp2)–H phosphorylation of enamides under transition-metal-free conditions

A visible-light-induced stereo- and regioselective phosphorylation of enamides with phosphine oxides under transition-metal-free conditions has been disclosed.

Limonitum Ameliorates Castor Oil-Induced Diarrhoea in Mice by Modulating Gut Microbiota

Diarrhoea is a common clinical condition; its pathogenesis is strongly associated with gut microbiota dysbiosis. Limonitum is a well-known traditional Chinese medicine that exerts appreciable benefits regarding the amelioration of diarrhoea. However, the mechanism through which Limonitum ameliorates diarrhoea remains unclear. Here, the efficacy and underlying mechanism of Limonitum decoction (LD) regarding diarrhoea were explored from the aspect of gut microbiota. Castor oil (CO) was used to induce diarrhoea in mice, which were then used to evaluate the effects of LD regarding the timing of the first defecation, diarrhoea stool rate, degree of diarrhoea, diarrhoea score, intestinal propulsive rate, and weight of intestinal contents. The concentrations of short-chain fatty acids (SCFAs), including acetic, propionic, isobutyric, butyric and valeric acids, were analysed by gas chromatography-mass spectrometry (GC-MS). The 16S rRNA high-throughput sequencing technology was applied to evaluate changes in the gut microbiota under exposure to LD. LD was found to effectively ameliorate the symptoms of diarrhoea, and the diversity and relative abundance of gut microbiota were restored to normal levels following LD treatment. Additionally, LD significantly restored the observed reductions in SCFAs. These results provide strong evidence that LD can sufficiently ameliorate diarrhoea in mice by regulating their gut microbiota. The findings presented here highlight that Limonitum may constitute a prospective remedy for diarrhoea.

Aptazyme-induced cascade amplification integrated with a volumetric bar-chart chip for highly sensitive detection of aflatoxin B1 and adenosine triphosphate

A triple-channel volumetric bar-chart chip based on aptazyme-induced cascade signal amplification empowers visual readout of aflatoxin B1 and adenosine triphosphate concentration.

Analysis of microbial diversity in the root of Astragalus mongholicus

Abstract The dry root of Astragalus mongholicus has therapeutic effects such as tonifing the middle - jiao, replenishing qi, solidifing the surface, promoting diuresis, dispelling sepsis outwards and nourishing muscle. There are some slices having black spots after slicing the root of astragalus. The diversity of endophytic fungi between slices with black spots and normal slices was analysed in this paper. The endophytic fungal sequences obtained by high-throughput sequencing were 298,044 and 297,396, and the 116 OTU subsets obtained after clustering belonged to 3 phyla, 9 classes, 22 orders, 38 families and 46 genera. The dominant classes were Eurotiomycetes and Leotiomycetes. The dominant order is Eurotiales and Helotiales. The dominant families are Helotiales_fam_Incertae_sedis and Aspergillaceae. The dominant genera are Cadophora and Aspergillus. There are some peculiar fungal flora in both normal slices and spotted slices. The study on endophytic fungi diversity of astragalus slices will provide some help for drug development of this plant.

[Safety and efficacy of laparoscopic microwave ablation combined with partial nephrectomy for renal tumors: initial experience]

Objective: To explore the safety and efficacy of laparoscopic microwave ablation combined with partial nephrectomy in the treatment of renal tumors. Methods: The 65 patients with renal tumors undergoing laparoscopic microwave ablation combined with partial nephrectomy from November 2017 to May 2021 were retrospectively analyzed. There were 46 males and 19 females. The average age was (56.6±14.1) years. The mean body mass index was (25.7±3.3) kg/m². The tumors located in the left kidney in 30 cases and the right kidney in 35 cases. The ECOG score was 0 in 59 patients and 1 in 6 patients. The mean maximum diameter of the tumors was (2.3±1.0) cm(1.0-5.0 cm). According to R.E.N.A.L. scoring, 41 cases were of low difficulty (4-6 points), 23 cases of medium difficulty (7-9 points) and 1 case of high difficulty (10-12 points). The renal tumors were ablated by laparoscopic microwave ablation, then followed by partial nephrectomy. Postoperative complications were observed and the prognosis was assessed by CT or MRI. Results: The mean duration of operation was (76.6±19.4) min (40-120 min). The median intraoperative blood loss was 20 ml(5-50 ml). The median duration of postoperative hospitalization was 4 d(3-6 d). Complications of Clavien grade Ⅰ were found in 11 patients (fever, nausea and vomiting, lumbar pain), and no complications were grade Ⅱ or above. Postoperative pathology showed that no positive margin was found, and 46 cases of clear cell renal cell carcinoma (AJCC stage: T_1a stage 42 cases, T_1b stage 4 cases; WHO/ISUP classification: 21 cases of grade 1, 23 cases of grade 2, 2 cases of grade 3); 2 cases of type 1 papillary renal cell carcinoma (stage T_1a, grade 1); 1 case of type 2 papillary renal cell carcinoma (T_1b stage, grade 2); 2 cases of renal chromophobe carcinoma (all stage T_1a); 1 case of low-grade malignant potential multilocular cystic renal tumor; 2 cases of adenocarcinoma (combined with the postoperative history of rectal cancer, metastasis was considered); 6 cases of renal angiomyolipoma; 2 cases of eosinophiloma; 1 case of papillary adenoma; 1 case of benign renal cyst and 1 case of renal hemangioma with calcification. The median follow-up was 24 months (1-42 months). Sixty-three patients survived and two died (one due to heart disease and one due to metastatic colorectal cancer). According to postoperative imaging, there were no signs of tumor recurrence or metastasis in other cases. Blood tests were performed regularly, and no significant abnormalities occurred. Conclusions: The safety and efficacy of laparoscopic microwave ablation combined with partial nephrectomy for the treatment of renal tumor is satisfactory, such as less intraoperative bleeding, fewer complications, less effect on renal function and postoperative pathology, providing a potential option for renal tumor treatment.

[Application of iris angiography combined with ultra-wide-field fundus fluorescein angiography in diabetic retinopathy]

Objective: To explore the application and value of iris angiography combined with ultra-wide-field fundus fluorescein angiography (UWFA) in diabetic retinopathy (DR). Methods: This was a cross-sectional study. From May 2016 to December 2019, 60 consecutive DR patients (120 eyes) including 30 patients (60 eyes) with severe non-proliferative DR (NPDR) and proliferative DR (PDR), respectively, who underwent iris angiography combined with UWFA in Tianjin Medical University Eye Hospital were enrolled in the study. There were 25 males and 35 females, with an average age of (53.5±10.7) years. All of the patients underwent ophthalmologic examination including visual acuity, intraocular pressure, slit-lamp microscopy, slit-lamp funduscopy, ultra-wide-field fundus photography, and iris angiography combined with UWFA. Iris angiography included iris fluorescein angiography (IFA) and iris indocyanine green angiography. The onset time of the iris vascular fluorescein leakage was recorded, and the circumference range of the pupil margin fluorescein leakage was measured by a self-developed software. Wilcoxon rank sum test was used to compare and analyze the difference in the onset time and the range of the iris vascular fluorescein leakage between the severe NPDR and PDR groups. Results: IFA showed that the onset time of the iris vascular fluorescein leakage was 31.00 (25.75, 34.00) s and 27.00 (21.75, 29.50) s in the severe NPDR group and the PDR group, respectively. The difference between two groups was statistically significant (Z=-2.13, P=0.033). The range of the iris vascular fluorescein leakage was 20.00(10.75, 75.00)° and 135.00(60.00, 182.50)° in the severe NPDR group and the PDR group, respectively. There was significant difference between two groups (Z=-4.23, P<0.001). Neovascularization of the iris was not found in all patients with PDR by slit-lamp microscope examination, but was found in 8 eyes by IFA and iris indocyanine green angiography. UWFA findings demonstrated that there was no strong fluorescence in retinal neovascularization elsewhere and/or neovascularization of the optic disc in severe NPDR patients. However, that could be seen in all PDR patients. Among them, 10 eyes had terminally petaloid or focal fluorescein leakage in macular area. Conclusions: Iris angiography combined with UWFA and quantitative analysis method could not only accurately assess the degree of fundus lesions, but also obtain more accurate and comprehensive iris vascular information, which provided help for comprehensive and personalized treatment of DR. (Chin J Ophthalmol, 2021, 57: 916-921).

Equine chorionic gonadotropin pretreatment 15 days before fixed-time artificial insemination improves the reproductive performance of replacement gilts

Fixed-time artificial insemination (FTAI) technology uses exogenous reproductive hormones to regulate the sexual cycle and ovulation of sows without oestrus identification, which improves the sow breeding utilisation rate, reduces the number of non-productive days, and elevates the efficiency of pig farm management. In this study, we aimed to optimise FTAI procedures. Healthy 190-day-old and about 90 kg Large White × Landrace crossing breed replacement gilts (n = 166) which were of unknown reproductive status were randomly selected and divided into three groups: a control group (n = 62), an eCG-15D group in which the gilts were pretreated with equine chorionic gonadotropin (eCG) injection 15 days before starting FTAI (n = 50), and an eCG-20D group pretreated with eCG injection 20 days before starting FTAI (n = 54). All three groups were then subjected to the same conventional FTAI procedure. Pigs were orally administered Altrenogest (ALT, 20 mg per pig per day) for 18 days and then 42 h after ALT feeding was stopped, they were injected with 1 000 IU eCG followed by 100 μg GnRH 80 h later. The gilts were inseminated for the first time 24 h after gonadotropin-releasing hormone (GnRH) injection and then again 16 h later. After 42 h of ALT feeding, gilts in the eCG-15D group displayed a higher follicular diameter until artificial insemination (AI) than those from the other groups (P < 0.05). In addition, the ovulation times were the most synchronised in the eCG-15D group, with 100% of the gilts ovulating before the second AI on day 25 of FTAI. Furthermore, the gilts in the eCG-15D group achieved the highest pregnancy rate (92%), farrowing rate (90%), total pigs born (11.59), and pigs born alive (11.18). Together, the findings of this study demonstrate that reproductive performance can be optimised by pretreating gilts with eCG 15 days before conventional FTAI.

[The clinical value of further accurate staging of pT2 gastric cancer based on the depth of invasion]

Objective: To investigate the clinical value of pT2 gastric cancer staging pT2a and pT2b according to the depth of muscularis propria invasion in evaluating the prognosis of gastric cancer. Methods: According to the 8th edition of TNM staging system for gastric cancer proposed by the Union for International Cancer Control (UICC) and the American Joint Committee on Cancer (AJCC), patients with gastric cancer who underwent radical surgery in the Fourth Hospital of Hebei Medical University from January 1, 2008 to January 1, 2015 were selected and divided into pT2a and pT2b stage group according to the depth of tumor invasion. The 5-year overall survival (OS) and disease-free survival (DFS) were compared between the two groups. Results: The median follow-up time of 1 411 patients with postoperative pathological pT2 stage was 68.8 months, and 1 347 patients (95.46%) received complete follow-up data. The 5-year OS rate was 65.85%, and the 5-year DFS rate was 67.83 %. The 5-year OS rate and 5-year DFS rate of 709 pT2a patients were 72.50% and 73.91%, respectively. The 5-year OS rate and 5-year DFS rate of 638 pT2b patients were 58.46% and 61.13%, respectively, significantly different from those of the pT2a group (P<0.001). Hierarchical analysis was performed according to N staging. The 5-year OS rates of pT2aN0M0 (274 cases), pT2aN1M0 (192 cases), pT2aN2M0 (147 cases), pT2aN3aM0 (59 cases) and pT2aN3bM0 (37 cases) were 83.58 %, 72.40 %, 68.71 %, 54.24 % and 35.12 %, respectively. The 5-year DFS rates were 84.67 %, 77.08 %, 67.35 %, 54.24 % and 35.14 %, respectively. In the pT2b group, the 5-year OS rates of pT2bN0M0 (209 cases), pT2bN1M0 (166 cases), pT2bN2M0 (127 cases), pT2bN3aM0 (78 cases) and pT2bN3bM0 (58 cases) were 76.08%, 62.05%, 56.69%, 37.18% and 17.24%, respectively, and the 5-year DFS rates were 80.86%, 69.28%, 54.33%, 35.90% and 15.52%, respectively. Under the same N stage, the OS rates of patients in the pT2a group were better than those in the pT2b group (P values were 0.023, 0.034, 0.034, 0.043 and 0.018, respectively). When the N stage was N0 and N1, there was no significant difference in the 5-year DFS rate between the pT2a group and the pT2b group (P values were 0.199 and 0.090, respectively). When the N stages were N2, N3a and N3b, the difference between the pT2a stage group and the pT2b stage group was statistically significant (P values were 0.027, 0.022 and 0.025, respectively). Conclusions: In the 8th edition of AJCC/UICC gastric cancer staging system, pT2 stage can be divided into pT2a stage (invasion of superficial muscularis) and pT2b stage (invasion of deep muscularis) according to the infiltration depth of muscularis propria. There are significant differences in prognosis between the two groups. Combined with the number of lymph node metastasis, the prognosis of patients with pT2 gastric cancer can be more accurately evaluated.