METTL3-mediated m6A modification of SOX4 regulates osteoblast proliferation and differentiation via YTHDF3 recognition.

N6-methyladenosine (m6A), the most prevalent internal modification in mRNA, is related to the pathogenesis of osteoporosis (OP). Although methyltransferase Like-3 (METTL3), an m6A transferase, has been shown to mitigate OP progression, the mechanisms of METTL3-mediated m6A modification in osteoblast function remain unclear. Here, fluid shear stress (FSS) induced osteoblast proliferation and differentiation, resulting in elevated levels of METTL3 expression and m6A modification. Through Methylated RNA Immunoprecipitation Sequencing (MeRIP-seq) and Transcriptomic RNA Sequencing (RNA-seq), SRY (Sex Determining Region Y)-box 4 (SOX4) was screened as a target of METTL3, whose m6A-modified coding sequence (CDS) regions exhibited binding affinity towards METTL3. Further functional experiments demonstrated that knockdown of METTL3 and SOX4 hampered osteogenesis, and METTL3 knockdown compromised SOX4 mRNA stability. Via RNA immunoprecipitation (RIP) assays, we further confirmed the direct interaction between METTL3 and SOX4. YTH N6-Methyladenosine RNA Binding Protein 3 (YTHDF3) was identified as the m6A reader responsible for modulating SOX4 mRNA and protein levels by affecting its degradation. Furthermore, in vivo experiments demonstrated that bone loss in an ovariectomized (OVX) mouse model was reversed through the overexpression of SOX4 mediated by adeno-associated virus serotype 2 (AAV2). In conclusion, our research demonstrates that METTL3-mediated m6A modification of SOX4 plays a crucial role in regulating osteoblast proliferation and differentiation through its recognition by YTHDF3. Our research confirms METTL3-m6A-SOX4-YTHDF3 as an essential axis and potential mechanism in OP.

Colonic mucosal diffuse congestion associated with Osimertinib.

INTRODUCTION: Non-small cell lung cancer (NSCLC) is the most common histological subtype of lung cancer. Osimertinib has been recommended as first-line treatment of advanced NSCLC with EGFR mutations. Previous studies have only reported cases of gastrointestinal bleeding due to Erlotinib and gefitinib, but to date, always no cases of gastrointestinal bleeding due to Osimertinib have been reported. CASE REPORT: We report a case of a female patient with NSCLC with EFGR mutation. After 1.5 years of treatment with Osimertinib, a colonoscopy showed diffuse congestion of the colonic mucosa. MANAGEMENT AND OUTCOME: The patient's symptoms of blood in the stool disappeared, after stopping Osimertinib and giving mucosal protection treatment for 1 week. DISCUSSION: Osimertinib may have contributed to gastrointestinal bleeding because no recurrent bleeding was observed after discontinuation of treatment. Physicians and patients should be aware that osimertinib may increase the risk of gastrointestinal bleeding.

A simple and rapid protein purification method based on cell-surface display of SUMO-fused recombinant protein and Ulp1 protease.

The development of novel methods for highly efficient protein purification remains a research focus in the biotechnology field because conventional purification approaches, including affinity purification, gel filtration, and ion-exchange chromatography, require complex manipulation steps and are costly. Here, we describe a simple and rapid protein purification strategy in which the SUMO tag and Ulp1 protease are surface-displayed separately on Escherichia coli cells. After protein induction, the cells are harvested, resuspended in cleavage buffer, and incubated together for cleavage. In this approach, the surface-displayed Ulp1 cleaves the membrane-anchored SUMO fusion protein, resulting in the release of the target protein from the C-terminal of SUMO into the solution. The bacterial cells harboring SUMO and Ulp1 on their surfaces can be easily removed by centrifugation. To evaluate the purification method, we used red fluorescent protein (mCherry). Purified mCherry protein (7.72 ± 1.05 mg from 1 L of bacterial culture) was obtained after only 30 min of incubation. The protein purity was higher than 80%, and could be further improved (> 90%) by simple ultrafiltration. This study offers a promising and simple strategy for the purification of recombinant protein in its native form that requires only cleavage and centrifugation steps.

Dose distribution of brachytherapy for locally advanced (stage IIB) cervical cancer.

PURPOSE: The aim of the study was to compare the dose distributions of combined intracavitary and interstitial (IC/IS) brachytherapy with 3-catheter IC brachytherapy in treating locally advanced (stage IIB) cervical cancer. METHODS AND MATERIALS: In total, 46 patients were included, each with stage IIB cervical cancer, local lesion sizes ≥5 cm, and tumors that had not regressed after 45 Gy/25 F external intensity-modulated radiotherapy. To identify the dosimetric advantage of delivering a local boost to high-risk (HR)-cervix in IC/IS, patients were divided into two groups: IC/IS and IC/IS + HR-cervix. The differences in dosimetric parameters were compared between the two groups. Comparisons were then made between the parameters of the four planning methods: IC (Point A), IC (three dimensional [3D]), IC/IS, and IC/IS + HR-cervix. RESULTS: In patients with IC/IS implants, the relative uterine tandem dwell time was significantly extended in the IC/IS + HR-cervix group, and the V150 and V200 volumes of HR-cervix were increased (all p < 0.001), whereas the D90 and D100 values of the IC/IS + HR-cervix group were lower than those in the IC/IS group. In pairwise comparisons, HR-cervix V150 and V200 values were lowest in the IC/IS group, followed by the IC (3D), IC/IS + HR-cervix, and IC (Point A) groups. All differences were statistically significant (p < 0.05), with the exception of IC/IS vs. IC (3D). CONCLUSIONS: When treating locally advanced cervical cancer (stage IIB, local residual volume ≥5 cm after external radiotherapy), the IC/IS + HR-cervix optimization method can meet the HR clinical target volume D90 dose requirement, normal tissue dose limits, and can escalate doses to local areas of the cervix.

Computed Tomography-Guided Interstitial Brachytherapy for Locally Advanced Cervical Cancer: Introduction of the Technique and a Comparison of Dosimetry With Conventional Intracavitary Brachytherapy.

OBJECTIVE: We present a new technique of 3-dimensional computed tomography-guided interstitial (IS) brachytherapy (BT) for locally advanced cervical cancer, offering a more advantageous clinical treatment approach. MATERIALS/METHODS: Interstitial BT was performed using an applicator combining uterine tandem and metal needles; needles were inserted freehand under real-time 3-dimensional computed tomography guidance. Twenty-eight patients with bulky tumors and/or parametrial extension (tumor size > 5 cm) after external beam radiotherapy received IS BT. Dosimetric outcomes of the IS BT including the total dose (external beam radiotherapy and high dose-rate BT) D90 for the high-risk clinical target volume (HR-CTV) and D2cc for the organs at risk (OARs) were investigated and compared with a former patient group consisting of 30 individuals who received the conventional intracavitary (IC) BT. RESULTS: The mean D90 values for HR-CTV in the IC BT and IS BT groups were 76.9 ± 5.7 and 88.1 ± 3.3 Gy, respectively. Moreover, 85.7% of the patients received D90 for HR-CTV of 87 Gy or greater in the IS BT group, and only 6.7% of the patients received D90 for HR-CTV of 87 Gy or greater in the IC BT group. The D2cc for the bladder, rectum, and sigmoid were 84.7 ± 6.8, 69.2 ± 4.2, and 67.8 ± 4.5 Gy in the IC BT group and 81.8 ± 6.5, 66.8 ± 4.0, and 64.8 ± 4.1 Gy in the IS BT group. The mean number of needles was 6.9 ± 1.4, with a mean depth of 2.9 ± 0.9 mm for each IS BT. Interstitial BT was associated with only minor complications. CONCLUSIONS: The IS BT technique resulted in better dose-volume histogram parameters for large volume tumors (>5 cm) compared with the conventional IC BT and acceptable risk of acute complications in locally advanced cervical cancer and is clinically feasible.

Salvage interstitial brachytherapy based on computed tomography for recurrent cervical cancer after radical hysterectomy and adjuvant radiation therapy: case presentations and introduction of the technique.

PURPOSE: Locally recurring cervical cancer after surgery and adjuvant radiotherapy remains a major therapeutic challenge. This paper presents a new therapeutic technique for such patients: interstitial brachytherapy (BT) guided by real-time three-dimensional (3D) computed tomography (CT). MATERIAL AND METHODS: Sixteen patients with recurrent cervical cancer after radical surgery and adjuvant external-beam radiotherapy (EBRT) were included in this study. These patients underwent high-dose-rate (HDR) interstitial BT with free-hand placement of metal needles guided by real-time 3D-CT. Six Gy in 6 fractions were prescribed for the high-risk clinical target volume (HR-CTV). D90 and D100 for HR-CTV of BT, and the cumulative D2cc for the bladder, rectum, and sigmoid, including previous EBRT and present BT were analyzed. Treatment-related complications and 3-month tumor-response rates were investigated. RESULTS: The mean D90 value for HR-CTV was 52.5 ± 3.3 Gy. The cumulative D2cc for the bladder, rectum, and sigmoid were 85.6 ± 5.8, 71.6 ± 6.4, and 69.6 ± 5.9 Gy, respectively. The mean number of needles was 6.1 ± 1.5, with an average depth of 3.5 ± 0.9 cm for each application. Interstitial BT was associated with minor complications and passable tumor-response rate. CONCLUSIONS: Interstitial BT guided by real-time 3D-CT for recurrent cervical cancer results in good dose-volume histogram (DVH) parameters. The current technique may be clinically feasible. However, long-term clinical outcomes should be further investigated.

Clinical feasibility of interstitial brachytherapy using a "hybrid" applicator combining uterine tandem and interstitial metal needles based on CT for locally advanced cervical cancer.

PURPOSE: To explore the dosimetric advantage of target volume and surrounding normal tissue by using interstitial (IS) brachytherapy (BT) based on three-dimensional CT in locally advanced cervical cancer, as a simple and effective clinical treatment approach. METHODS AND MATERIALS: Fifty-two patients with poor tumor response to external beam radiotherapy and a residual tumor >5 cm at the time of the first BT were included. IS BT was performed using a "hybrid" applicator combining uterine tandem and free metal needles based on three-dimensional CT. The high-risk clinical target volume (HR-CTV), intermediate-risk clinical target volume, and organs at risk were contoured. The total dose, including external beam radiotherapy (45 Gy in 25 fractions) and high-dose-rate BT (30 Gy in 5 fractions), was biologically normalized to conventional 2-Gy fractions. D90 and D100 for HR-CTV and intermediate-risk clinical target volume and D2cc for the bladder, rectum, and sigmoid were analyzed. RESULTS: The mean D90 value for HR-CTV was 88.4 ± 3.5 Gy. Totally, 88.5% of the patients received D90 for HR-CTV ≥87 Gy. The D2cc for the bladder, rectum, and sigmoid were 81.1 ± 5.6, 65.7 ± 5.1, and 63.1 ± 5.4 Gy, respectively. The mean number of needles was 6.9 ± 1.3 for each application. IS BT was associated with minor complications. CONCLUSION: IS BT using the "hybrid" applicator provides a dosimetric advantage for target volume and organs at risk in large-volume (>5 cm) tumors and is, thereby, clinically feasible. However, the long-term curative effect and possible toxicity need further clinical observation.

[Effects of leflunomide on podocytes exposed to high glucose condition and its mechanism].

OBJECTIVE: To explore the protective effects of leflunomide (A771726) on the expression of podocalyxin, NF-κB and matrix metalloproteinase-9 (MMP-9) in podocytes exposed to high glucose environment and elucidate its mechanism. METHODS: Podocytes were cultured in high glucose. And the altered expressions of podocyte protein podocalyxin were detected by Western blotting at different timepoints. Then podocytes were divided into 4 groups of normal glucose control, leflunomide, high glucose and hypertonic control. The expression level of podocalyxin protein in each group was detected by Western blotting. And NF-κB p65 and phosphorylation of NF-κB p65 (P-NF-κBp65) in podocytes cultured in high glucose were detected at different timepoints. And then the podocytes were divided into 5 groups of normal glucose, mannitol, hypertonic control, high glucose, leflunomide and PDTC (NF-κB blocker). And the expressions of MMP-9 protein in these groups were also detected by Western blotting. RESULTS: In the high glucose environment, the expression of podocalyxin declined instantly. Compared with the high-glucose group, the podocalyxin expression of the leflunomide group was significantly higher than the high glucose group (0.46 ± 0.04 vs 0.13 ± 0.03, P < 0.05). After 30-minute stimulation by high glucose, the activation of NF-κB started and the expression of P-NF-κBp65 protein increased. Such activities peaked at 60 minutes and reverted to a basic level after 6 hours. Compared with the high glucose group, the expressions of MMP-9 in PDTC and leflunomide groups were significantly lower than the high glucose group. And the differences were statistically significant (0.71 ± 0.01, 0.64 ± 0.03 vs 1.64 ± 0.03, both P < 0.05). CONCLUSIONS: Leflunomide has protective effects on podocytes in high glucose. And its mechanism is possibly due to a lowered expression of MMP-9 through an inhibition of NF-κB activation.

Experimental study of leflunomide on renal protective effect and on inflammatory response of streptozotocin induced diabetic rats.

AIM: To further reveal the effects of leflunomide on renal protection and on inflammatory response using streptozotocin (STZ) induced diabetic rats. METHODS: Male Wistar rats were randomly divided into normal control group (NC), diabetic group (DM) and leflunomide treatment group (LEF). LEF group rats were given leflunomide (5 mg/kg) once daily. At the end of the 12th week, general biochemical parameters in three groups were determined. The renal histopathology was observed by light microscopy and electron microscopy. Further biochemical analysis of the gene and protein expression of nuclear factor kappa B (NF-κB), tumour necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) and ED-1 positive cells in renal tissue were provided using real-time reverse transcription-polymerase chain reaction and immunohistochemistry. RESULTS: Compared with NC group rats, systolic blood pressure, blood glucose (BG), glycohemoglobin (HbAlc), renal hypertrophy index, urine albumin excretion rate (AER) and serum creatinine were increased in DM group rats (P < 0.05). Treatment with leflunomide can improve these parameters except systolic blood pressure, BG and HbAlc. Creatinine clearance rate (Ccr) in the DM group was significantly lower than that of the NC group, and leflunomide can increase its level. Compared with DM group rats, the pathological damages were significantly relieved in LEF group rats. Compared with NC group rats, the gene and protein expressions of NF-κB, TNF-α, MCP-1 and ED-1 positive cells in renal tissue of DM group rats were highly upregulated (P < 0.01). Leflunomide suppressed their high expressions in renal tissue of diabetic rats. CONCLUSIONS: Leflunomide can ameliorate the kidney structure and function injury of diabetic rats through suppressing the expression of NF-κB, TNF-α, MCP-1 and macrophage infiltration in renal tissue.

Effect of activin A on tubulointerstitial fibrosis in diabetic nephropathy.

AIM: The effect of activin A on tubulointerstitial fibrosis in diabetic nephropathy (DN) using streptozotocin (STZ)-induced diabetic rats and high glucose-cultured HK-2 cells was investigated. METHODS: Male Wistar rats were randomized into a normal control group (NC) and diabetes mellitus group (DM). Diabetes was induced by i.p. injection of STZ. Six rats were respectively killed 4, 8, 12 and 16 weeks after model establishment in each group. The changes of kidney weight/bodyweight (KW/BW), urine albumin excretion rate (AER) and creatinine clearance rate (Ccr) were determined. The morphology of tubulointerstitium was observed by light microscopy. Further biochemical analysis was provided using immunohistochemistry and real-time polymerase chain reaction. The different parameters in high glucose-cultured HK-2 cells were monitored by western blotting or enzyme-linked immunosorbent assay (ELISA) and the intervention of rh-follistatin on them was investigated. RESULTS: Compared with the NC group, there was marked enlargement in the levels of KW/BW, AER, Ccr and interstitial fibrosis index, and the production of P-Smad2/3 and fibronectin in the DM group from 8 to 16 weeks. Activin betaA, mainly located in tubular epithelial cells, was significantly higher in the DM group than that in the NC group throughout the study periods. Follistatin was abundant in the NC group, but was diminished gradually in the DM group. High glucose may facilitate the synthesis of activin betaA, transforming growth factor (TGF)-beta, P-Smad2/3 and fibronectin in HK-2 cells while rh-follistatin inhibited them except TGF-beta. CONCLUSION: Activin A is involved in tubulointerstitial fibrosis in DN by inducing the production of fibronectin through Smad signal pathway.

Towards more efficient glutathione peroxidase mimics: substrate recognition and catalytic group assembly.

Glutathione peroxidase (GPX) is a well-known selenoenzyme that functions as an antioxidant and catalyzes the reduction of harmful peroxide by glutathione and protects cells against oxidative damage. Because many diseases are related to oxidative stress, GPX is an ancient foe of many diseases. Antioxidants are very useful for biological bodies, and considerable effort has been spent to find compounds that could imitate the properties of GPX. This paper reviews GPX mimics developed so far and describes a new, more effective strategy for fabricating them. Although many GPX mimics have been made, they possess serious disadvantages: low activity, low solubility in water, and, in some cases, toxicity. In order to overcome these drawbacks, we have proposed a new strategy of imitating GPX. First, a receptor with a substrate binding site is generated. Next, a catalytic group is incorporated into the receptor near the substrate binding site, allowing the catalytic group access to the functional group of the substrate. Finally, a highly efficient enzyme mimic is obtained. Using this strategy, we successfully fabricated GPX mimics that use antibodies, cyclodextrins, some enzymes and proteins as receptors and chemical modification to incorporate the catalytic group, selenocysteine (Sec). The general principle of combining a functional group involved in catalysis with a specific binding site for the substrate is an approach that could be applied to the generation of other efficient semisynthetic biocatalysts. We describe the antioxidant activities of these GPX mimics and the reasons of their being promising candidates for medicinal applications.