General Control Non-derepressible 2 Alleviates Cartilage Degeneration and Inhibits NLRP3 Inflammasome Activation in Osteoarthritis.

This study aimed to evaluate the effects of general control non-derepressible 2 (GCN2) on osteoarthritis (OA) in vivo and in vitro. First, anterior cruciate ligament transection (ACLT)-induced rat model and interleukin (IL)-1ß-induced ATDC5 chondrocyte were established. Hematoxylin and eosin staining and safranin O/fast green staining were employed for analyzing the histological changes in the rat cartilage. In addition, immunohistochemistry, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, western blot, and immunofluorescence staining were employed for examining cartilage degeneration-, inflammation-, autophagy-, and NLR family pyrin domain containing 3 (NLRP3) inflammasome-associated genes expression. Moreover, 2,7-dichlorodihydrofluorescein acetoacetic acid probe was utilized for examining the intracellular reactive oxygen species. In addition, 5-ethynyl-2'-deoxyuridine assay and flow cytometry were applied for detecting chondrocyte proliferation and apoptosis IL-1ß-treated ATDC5 chondrocytes. GCN2 overexpression ameliorated articular cartilage degeneration and inflammation but promoted chondrocyte autophagy in ACLT-induced OA rats. Similarly, we demonstrated that the upregulation of GCN2 could promote chondrocyte proliferation, suppress chondrocyte apoptosis, attenuate chondrocyte inflammation and extracellular matrix degradation, and promote chondrocyte autophagy. Moreover, GCN2 overexpression could inhibit the activation of NLRP3 inflammasome in IL-1ß-induced ATDC5 chondrocyte. Furthermore, 3-methyladenine neutralized the protective and autophagy-promoting effects of GCN2 overexpression on ATDC5 chondrocytes. GCN2 could attenuate inflammation and cartilage degeneration, promote chondrocyte autophagy, and inhibit NLRP3 inflammasome activation in OA.

Long Non-Coding RNA ZSCAN16-AS1 Promotes the Malignant Progression of Melanoma Through Regulating the miR-503-5p/ARL2 Axis.

Background: LncRNA zinc finger and SCAN domain containing 16 antisense RNA 1 (ZSCAN16-AS1), a newly identified lncRNA, has been proven to accelerate hepatocellular carcinoma progression. However, the function and molecular mechanism of ZSCAN16-AS1 in melanoma are still unknown. Methods: The level of ZSCAN16-AS1 in melanoma tissues was detected and reported in The Cancer Genome Atlas (TCGA) and GEO#GSE15605. CCK-8, Transwell and flow cytometry assays were used to explore the role of ZSCAN16-AS1 in melanoma cells. Luciferase reporter assays and RNA pull-down assays were used to verify the molecular mechanism of ZSCAN16-AS1. Results: Here, we found that ZSCAN16-AS1 expression was increased in melanoma. We confirmed that ZSCAN16-AS1 promotes the growth and metastasis of melanoma. ZSCAN16-AS1 exerts its pro-tumour role through sponging of miR-503-5p to liberate ADP-ribosylation factor-like protein 2 (ARL2) mRNA transcripts. Conclusion: These results demonstrated the role and molecular mechanism of ZSCAN16-AS1 in the occurrence and development of melanoma. Therefore, ZSCAN16-AS1 may be used as a specific biomarker in the diagnosis and treatment of melanoma patients.

Inverse relationship between femoral lateralization and neck-shaft angle is a joint event after intramedullary nailing of per trochanteric fractures.

This study explored the relationship between femoral lateralization and femoral neck-shaft angle after intramedullary nail (IM) fixation for per trochanteric fractures. 70 patients (AO/OTA 31A1-2) were investigated. Anteroposterior (AP) and lateral X-ray views pre- and post-operation were recorded. Patients were classified into three groups according to the position of the medial cortex of the head-neck fragment to that of the femoral shaft: being slightly superomedial (positive medial cortex support, PMCS), being smoothly contacted (neutral position, NP) or being displaced laterally (negative medial cortex support, NMCS). Patient demographics, femoral lateralization, and neck-shaft angle were measured and statistically analyzed pre- and post-operation. Functional recovery was evaluated by Harris score 3- and 6- months post-operation. All cases ultimately demonstrated radiographic fracture union. There was a tendency to have an increased neck-shaft angle (valgus alignment) in the PMCS group and increased femoral lateralization in the NP group (p < 0.05). Among those three groups, the change in femoral lateralization and neck-shaft angle was statistically different (p < 0.05). An inverse relationship between femoral lateralization and femoral neck-shaft angle was observed. Femoral lateralization increased correspondingly when the neck-shaft angle continuously decreased from the PMCS group to the NP group and then to the NMCS group, and patients in the PMCS group had better functional recovery than the other two groups (p < 0.05). Femoral lateralization was commonly produced after IM fixation for per trochanteric fractures. The fracture fixed in PMCS mode possesses the slightest change in femoral lateralization while maintaining valgus alignment of the femoral neck-shaft angle and good functional outcome, which is superior to NP or NMCS mode.

Analysis of Energy and Density in Treating Hypertrophic Scar After Burn in Children with CO2 Dot Matrix Laser.

Objective: To analyze and compare the effect of the combination of energy and density parameters of CO2 dot matrix laser in the hyperplastic stage of pediatric burn. Materials and Methods: A total of 160 pediatric patients with hypertrophic scar after limb burn from 2017 to 2020 were randomly divided into four parameter groups (n = 40). The patients were treated with ablative fraction carbon dioxide laser, once every 10 weeks. During the interval of laser treatment, Compound Heparin Sodium and Allantoin Gel (Contractubex) was applied externally, tid, and elastic cover or elastic bandage is attached to the affected limb. Scoring based on the Vancouver Scar Scale is performed before each laser treatment, The score before the first treatment was the initial score, which was scored by two people separately, and the average score was calculated. Subsequently, the patients were treated four times and scored. The differences between each treatment and the first score of each parameter group were compared. Under the same energy and different treatment density, the scores after each treatment were compared. Under the same density and different energy, the scores after each treatment were compared. The bleeding and pigmentation of each parameter group were compared. Results: The increase of density can show the therapeutic effect earlier than the increase of energy, and 25mj energy and 10% density have better intervention effect. With the course of disease and the progress of treatment, the correlation between intervention effect and parameters tends to weaken. Comparing the number of cases with different scores between each treatment and the first time, the score in the 5% density group was lower than that in the 10% density group, but there was no significant difference between the 25mj and 17.5mj energy levels in the same density group. The intervention effect of the increase of density on scar was better than that of energy, and the increase of energy and density could aggravate the pain. Conclusion: In pediatric burn hypertrophic scars treated by CO2 dot matrix laser in exfoliation mode, the intervention effect of increasing density is better than that of energy. When setting laser treatment parameters, we should give priority to increasing density and adjust energy according to the effect of treatment and the condition of pain, bleeding and color precipitation. In this study, the best combination of parameters is 17.5mj/10%.

hUC-MSCs exosomal miR-451 alleviated acute lung injury by modulating macrophage M2 polarization via regulating MIF-PI3K-AKT signaling pathway.

In the previous study, we have proved that exosomal miR-451 from human umbilical cord mesenchymal stem cells (hUC-MSCs) attenuated burn-induced acute lung injury (ALI). However, the mechanism of exosomal miR-451 in ALI remains unclear. Therefore, this study aimed to study the molecular mechanism of hUC-MSCs-derived exosomal miR-451 on ALI by regulating macrophage polarization. Exosomes were isolated and identified by transmission electron microscope (TEM) and nanoparticle tracking analysis (NTA). The expression of miR-451, macrophage migration inhibitory factor (MIF) and PI3K/AKT signaling pathway proteins were detected by qRT-PCR and western blot. Flow cytometry was used to detect the CD80 and CD206 positive cells. Severe burn rat model was established and HE was used to detect the inflammatory cell infiltration and inflammatory injury. Dual luciferase reporter system was used to detect the regulation of miR-451 to MIF. The contents of cytokines were detected by ELISA. The results showed that hUC-MSCs exosomes promoted macrophage M1 to M2 polarization. Furthermore, hUC-MSCs-derived exosomal miR-451 alleviated ALI development and promoted macrophage M1 to M2 polarization. Moreover, MIF was a direct target of miR-451. Downregulation of MIF regulated by miR-451 alleviated ALI development promoted macrophage M1 to M2 polarization. In addition, we found that MIF and hUC-MSCs-derived exosomal miR-451 participated in ALI by regulating PI3K/AKT signaling pathway. In conclusion, we indicated that hUC-MSCs-derived exosomal miR-451 alleviated ALI by modulating macrophage M2 polarization via regulating MIF-PI3K-AKT signaling pathway, which provided great scientific significance and clinical application value for the treatment of burn-induced ALI.

Analysis of the therapeutic effect of artificial leather embedding combined with fascial sleeve flap transplantation on chronic wounds of lower limbs with bone and plate exposure.

BACKGROUND: After severe trauma of lower limbs, bone, tendon or plate graft exposure is common. The traditional repair method is to use a variety of skin flap transplantation to cover the exposed part, but the wound often can not heal after operation, or the wound is cracked, ulcer, sinus, bone and steel plate are exposed again after wound healing. The reason for this result is that when the flap is covered, the space around the bone plate is not well closed, forming a dead cavity, blood and exudate accumulation, hematoma formation or infection, and finally the wound ruptures again. In addition, due to the swelling and contracture of the flap after operation, the suture tension between the flap and the receiving area becomes larger, the skin becomes thinner and broken, and then the wound is formed. In order to solve the above problems, we carried out the study of artificial true skin embedding combined with fascial sleeve flap transplantation in the treatment of chronic bone plate exposed wounds of lower limbs. METHODS: In this paper, 11 cases of chronic wounds with bone exposure and skin necrosis after steel plate implantation were selected. First stage is the wound bed preparation including primary wound expansion, removal of necrotic tissue and incision of sinus wall, removal of deep necrotic bone and fibrotic scarred skin on the outer wall of steel plate to normal tissue on the outer edge of the wound, removal of precipitated peptone and purulent fur in the hole, periphery and bone space of the steel plate, and removal of tendon tissue with basal necrosis and disintegration of the wound. After vacuum sealing drainage (VSD) 1-2 weeks, the peritraumatic basal granulation tissue grew well and there was no necrotic tissue in the wound. In the second stage, the exposed bone was covered with artificial dermis, the steel plate hole or the periphery and the basal space were filled, and the exposed steel plate was completely embedded, and then the fascia sleeve flap was transplanted to cover the wound. The sural neurovascular flap was performed in nine cases and the lateral superior malleolar artery perforator flap in two case. RESULTS: The flap survived well in all 11 cases. During the follow-up of 6 months to the removal of the plate, there was no case of rupture, exposure and sinus formation. CONCLUSIONS: Artificial dermal covering combined with fascial sleeve flap transplantation can effectively avoid wound dehiscence or sinus formation caused by foreign body retention, infection and flap contracture. It has good effect in repairing chronic wounds with bone plate exposure after severe trauma of lower limbs.

O-Succinyl-l-homoserine overproduction with enhancement of the precursor succinyl-CoA supply by engineered Escherichia coli.

O-Succinyl-l-homoserine (OSH) is an important platform chemical in production of C4 chemicals such as succinic acid, homoserine lactone, γ­butyrolactone, and 1,4­butanediol. The production of OSH through chemical method or the current engineering strain is difficult and not optimal, and thereby there remains a need to develop new engineering strategy. Here, we engineered an OSH overproducing Escherichia coli strain through deleting the degradation and competitive pathways, overexpressing thrA and metL to enhance the metabolic flux from l-asparate to l-homoserine. Additionally, increasing the precursor succinyl-CoA supply through simultaneously knocking out sucD and overexpressing sucA further increased the yield of OSH. The engineered strain OSH9/pTrc-metA11-yjeH with above strategies produced OSH at the concentration of 24.1 g/L (0.609 g/g glucose) in batch fermentation. To gain detailed insight into metabolism of the engineered strain, comparative metabolic profiling was performed between the engineered and wide-type strain. The metabolomics data deciphered that the carbon was directed toward the OSH biosynthesis resulting in less flexibility of the genetically modified strain than the wide-type strain.

Increasement of O-acetylhomoserine production in Escherichia coli by modification of glycerol-oxidative pathway coupled with optimization of fermentation.

OBJECTIVE: O-acetylhomoserine (OAH) is an important platform chemical to produce high-valuable chemicals. To improve the production of O-acetylhomoserine from glycerol, the glycerol-oxidative pathway was investigated and the optimization of fermentation with crude glycerol was carried out. RESULTS: The glycerol-uptake system and glycerol-oxidative pathway were modified and O-acetyltransferase from Corynebacterium glutamicum was introduced into the engineered strain to produce O-acetylhomoserine. It was found that overexpression of glycerol 3-phosphate dehydrogenase improved the OAH production to 6.79 and 4.21 g/L from pure and crude glycerol, respectively. And the higher OAH production depending on higher level of transcription of glpD. Two-step statistical approach was employed to optimize the fermentation conditions. The significant effects of glycerol, ammonium chloride and yeast extract were screened applying Plackett-Burman design and were optimized further by employing the Response Surface Methodology. Under optimized conditions, the OAH production was up to 9.42 and 7.01 g/L when pure and crude glycerol were used in shake flask cultivations, respectively. CONCLUSIONS: The enzymatic step catalyzing the oxidation of glycerol through GlpD was the key step for OAH production, which served the foundation for realization of a consistent OAH production from crude glycerol in the future.

Exosomal miR-451 from human umbilical cord mesenchymal stem cells attenuates burn-induced acute lung injury.

BACKGROUND: The aim of this study was to investigate the molecular mechanism of human umbilical cord mesenchymal stem cells (MSCs)-derived exosomes (hUCMSC-Exos) in regulating burn-induced acute lung injury (ALI). METHODS: In this study, we initially isolated exosomes from hUCMSCs and identified them by transmission electron microscopy. The expression of the protein markers CD9 and CD63 in the exosomes was determined by western blot analysis. The expression of miR-451 in the hUCMSC-Exos was determined by qRT-PCR. The levels of TNF-α, IL-1ß, and IL-6 in lung tissues and serum as well as the levels of malondialdehyde, myeloperoxidase, superoxide dismutase in lung tissues were detected by ELISA. Hematoxylin-eosin stain was used to observe the morphological changes of lung tissues after burn. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assays were performed to detect apoptosis in lung tissues after burn. The expression of proteins related to the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway in lung tissues after burn was analyzed by western blotting. RESULTS: Our results showed that hUCMSC-Exos successfully decreased TNF-α, IL-1ß, and IL-6 levels in rats after burn, and this reduction was reversed when the miR-451 expression in the hUCMSC-Exo group was inhibited. HUCMSC-Exo-derived miR-451 improves ALI via the TLR4/NF-κB pathway. CONCLUSION: We demonstrated that exosomes derived from hUCMSCs mediate miR-451 to attenuate burn-induced ALI.

Effect of Netrin-1 Anti-Inflammatory Factor on Acute Lung Injury in Sepsis Rats.

BACKGROUND Acute lung injury (ALI) often occurs early and seriously in the progress of sepsis. Netrin-1 is demonstrated to be an effective anti-inflammatory agent. However, whether netrin-1 can relieve sepsis-induced ALI remains unknown. MATERIAL AND METHODS The sepsis rat model was built with the method of cecal ligation and puncture (CLP). The lung tissue changes were represented as the results of hematoxylin-eosin (HE) staining, wet-to-dry (W/D) ratio, Western blot analysis, and immunohistochemistry. An in vitro lung injury model was simulated with LPS-induced BEAS-2B cells. The cell transfection effects were evaluated by Western blot analysis and RT-qPCR analysis. TNF-alpha, IL-1ß, and IL-6 levels were detected by Western blot analysis in LPS-induced BEAS-2B cells. RESULTS Obvious inflammation caused by sepsis appeared in lung tissues with the increase of the W/D ratio and expression of inflammatory cytokines. Netrin-1 and its receptor UNC5B were reduced in sepsis. However, upregulation of netrin-1 alleviated the levels of inflammation and increased the UNC5B levels in BEAS-2B cells. CONCLUSIONS Netrin-1 protects against ALI in sepsis rats through its anti-inflammation effect and may provide a novel treatment to prevent lung injury caused by sepsis.

Chemical Composition and Source Apportionment of PM2.5 in Urban Areas of Xiangtan, Central South China.

Xiangtan, South China, is characterized by year-round high relative humidity and very low wind speeds. To assess levels of PM2.5, daily samples were collected from 2016 to 2017 at two urban sites. The mass concentrations of PM2.5 were in the range of 30⁻217 µg/m³, with the highest concentrations in winter and the lowest in spring. Major water-soluble ions (WSIIs) and total carbon (TC) accounted for 58⁻59% and 21⁻24% of the PM2.5 mass, respectively. Secondary inorganic ions (SO42-, NO3-, and NH4⁺) dominated the WSIIs and accounted for 73% and 74% at the two sites. The concentrations of K, Fe, Al, Sb, Ca, Zn, Mg, Pb, Ba, As, and Mn in the PM2.5 at the two sites were higher than 40 ng/m³, and decreased in the order of winter > autumn > spring. Enrichment factor analysis indicates that Co, Cu, Zn, As, Se, Cd, Sb, Tl, and Pb mainly originates from anthropogenic sources. Source apportionment analysis showed that secondary inorganic aerosols, vehicle exhaust, coal combustion and secondary aerosols, fugitive dust, industrial emissions, steel industry are the major sources of PM2.5, contributing 25⁻27%, 21⁻22%, 19⁻21%, 16⁻18%, 6⁻9%, and 8⁻9% to PM2.5 mass.

Investigation of the key factors on 3-hydroxypropionic acid production with different recombinant strains.

3-Hydroxypropionic acid (3-HP) is an important compound and precursor for a series of chemicals and polymeric materials. In this study, the 3-HP producing bacteria were constructed and studied for efficient synthesis of 3-HP. The results indicated that the instability of glycerol dehydratase (GDHt) affected the 3-HP production significantly, which was successfully solved by the expression of glycerol dehydratase reactivase (GdrB), with fivefold increase in 3-HP yield. Meanwhile, NAD+-regenerating enzymes GPD1 (glycerol-3-phosphate dehydrogenase) was expressed; however, the results showed 3-HP was significantly decreased from 56.73-4 mM, and malic acid was obviously increased. Analysis of the C flux distribution showed that the main reason for the results was the lack of NAD+. The addition of NAD+ further increased the 3-HP production to 23.87 mM, demonstrating that the "regeneration of NAD+" was the major factor for enhancing 3-HP production.

Rapid degradation of endosulfan by zero-valent zinc in water and soil.

Endosulfan has been included in the list of persistent organic pollutants (POPs) in 2011. The degradation of endosulfan by zero-valent zinc in water and soil was first investigated. The results showed that >90% endosulfan could be degraded in 180 min. The degradation was accelerated under acidic conditions with the absence of dissolved oxygen, while the nature of the soil only exhibited a negligible effect. The half-life was decreased from 130.75 min to 41.75 min with the increment of Zn(0) from 0.1 g to 1 g in soil. The use of Zn(0) was more effective than Fe(0) for the degradation of endosulfan with a half-life of 110 min and 330 min. The cationic surfactant was more effective at enhancing the degradation of endosulfan than anionic and nonionic surfactant. The degradation pathway was speculated, and four chlorine of endosulfan were proposed to be reduced. The method exhibited obvious advantages over traditional endosulfan treatments, and the research results will lay a foundation for practical application of the method.

Enantioselective bioactivity, acute toxicity and dissipation in vegetables of the chiral triazole fungicide flutriafol.

The enantioselective bioactivity, acute toxicity and stereoselective degradation of the chiral triazole fungicide flutriafol in vegetables were investigated for the first time using the (R)-, (S)- and rac-flutriafol. The order of the bioactivity against five target pathogens (Rhizoctonia solani, Alternaria solani, Pyricularia grisea, Gibberella zeae, Botrytis cinerea) was found to be (R)-flutriafol>rac-flutriafol>(S)-flutriafol. The fungicidal activity of (R)-flutriafol was 1.49-6.23 times higher than that of (S)-flutriafol. The (R)-flutriafol also showed 2.17-3.52 times higher acute toxicity to Eisenia fetida and Scenedesmus obliquus than (S)-flutriafol. The stereoselective degradation of flutriafol in tomato showed that the active (R)-flutriafol degraded faster, resulting in an enrichment of inactive (S)-form, and the half-lives were 9.23 d and 10.18 d, respectively. Inversely, the (S)-flutriafol, with a half-life of 4.76 d, was preferentially degraded in cucumber. In conclusion, the systemic assessments of the triazole fungicide flutriafol stereoisomers on the enantioselective bioactivity, acute toxicity and environmental behavior may have implications for better environmental and ecological risk assessment.

Detecting clothianidin residues in environmental and agricultural samples using rapid, sensitive enzyme-linked immunosorbent assay and gold immunochromatographic assay.

Two rapid, sensitive immunoassays based on monoclonal antibody for detecting clothianidin were developed and applied in agricultural samples: a quantitative enzyme-linked immunosorbent assay (ELISA) and a semiquantitative gold immunochromatographic assay (GICA). Under optimal conditions, the half-maximal inhibition concentration (IC50) and the limit of detection (LOD, IC10) of clothianidin were 25.6 and 3.8 ng mL(-1) for ELISA. GICA using colloidal gold-MAb probe had a visual detection limit of 8 ng mL(-1), and the results can be judged by the naked eye within 10 min. The cross-reactivities of the immunoassays with its analogues were negligible except for that with dinotefuran. For the spiked agricultural samples, recoveries of 78.0 to 114.5% with relative standard deviations (RSDs) of 3.2 to 12.8% were achieved for ELISA and further evaluated by GICA. Furthermore, the results of ELISA and GICA for the authentic samples correlated well with those obtained by HPLC. Overall, the proposed ELISA and GICA are satisfactory for rapid, sensitive, and quantitative/semiquantitative detection of clothianidin residues in agricultural samples.