Combining fecal 16 S rRNA sequencing and spinal cord metabolomics analysis to explain the modulatory effect of PPARα on neuropathic pain

BACKGROUND

Existing evidence suggests that the composition of the gut microbiota is associated with neuropathic pain (NP), but the mechanistic link is elusive. Peroxisome proliferator-activated receptor α (PPARα) has been shown to be a pharmacological target for the treatment of metabolic disorders, and its expression is also involved in inflammatory regulation. The aim of this study was to investigate the important modulatory effects of PPARα on gut microbiota and spinal cord metabolites in mice subjected to chronic constriction injury.

METHODS

We analyzed fecal microbiota and spinal cord metabolic alterations in mice from the sham, CCI, GW7647 (PPARα agonist) and GW6471 (PPARα antagonist) groups by 16 S rRNA amplicon sequencing and untargeted metabolomics analysis. On this basis, the intestinal microbiota and metabolites that were significantly altered between treatment groups were analyzed in a combined multiomics analysis. We also investigated the effect of PPARα on the polarization fractionation of spinal microglia.

RESULTS

PPARα agonist significantly reduce paw withdrawal threshold and paw withdrawal thermal latency, while PPARα antagonist significantly increase paw withdrawal threshold and paw withdrawal thermal latency. 16 S rRNA gene sequencing showed that intraperitoneal injection of GW7647 or GW6471 significantly altered the abundance, homogeneity and composition of the gut microbiome. Analysis of the spinal cord metabolome showed that the levels of spinal cord metabolites were shifted after exposure to GW7647 or GW6471. Alterations in the composition of gut microbiota were significantly associated with the abundance of various spinal cord metabolites. The abundance of Licheniformes showed a significant positive correlation with nicotinamide, benzimidazole, eicosanoids, and pyridine abundance. Immunofluorescence results showed that intraperitoneal injection of GW7647 or GW6471 altered microglial activation and polarization levels.

CONCLUSION

Our study shows that PPARα can promote M2-type microglia polarization, as well as alter gut microbiota and metabolites in CCI mice. This study enhances our understanding of the mechanism of PPARα in the treatment of neuropathic pain.

[Improvement effect of cinnamaldehyde on reserpine-induced Parkinson's disease rat model]

In order to study the neuroprotective mechanism of cinnamaldehyde on reserpine-induced Parkinson's disease(PD) rat models, 72 male Wistar rats were randomly divided into blank group, model group, Madopar group, and cinnamaldehyde high-, medium-, and low-dose groups. Except for the blank group, the other groups were intraperitoneally injected with reserpine of 0.1 mg·kg~(-1) once every other morning, and cinnamaldehyde and Madopar solutions were gavaged every afternoon. Open field test, rotarod test, and oral chewing movement evaluation were carried out in the experiment. The brain was taken and fixed. The positive expression of dopamine receptor D1(DRD1) was detected by TSA, and the changes in neurotransmitters such as dopamine(DA) and 3,4-dihydroxyphenylacetic acid(DOPAC) in the brain were detected by enzyme-linked immunosorbent assay(ELISA). The protein and mRNA expression levels of tyrosine hydroxylase(TH) and α-synuclein(α-Syn) in substantia nigra(SN) were detected by RT-PCR and Western blot. The results showed that after the injection of reserpine, the hair color of the model group became yellow and dirty; the arrest behavior was weakened, and the body weight was reduced. The spontaneous movement and exploration behavior were reduced, and the coordination exercise ability was decreased. The number of oral chewing was increased, but the cognitive ability was decreased, and the proportion of DRD1 positive expression area in SN was decreased. The expression of TH protein and mRNA was down-regulated, and that of α-Syn protein and mRNA was up-regulated. After cinnamaldehyde intervention, it had an obvious curative effect on PD model animals. The spontaneous movement behavior, the time of staying in the rod, the time of movement, the distance of movement, and the number of standing times increased, and the number of oral chewing decreased. The proportion of DRD1 positive expression area in SN increased, and the protein and mRNA expression levels of α-Syn were down-regulated. The protein and mRNA expression levels of TH were up-regulated. In addition, the levels of DA, DOPAC, and homovanillic acid(HVA) neurotransmitters in the brain were up-regulated. This study can provide a new experimental basis for clinical treatment and prevention of PD.

Insecticide resistance monitoring of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) and its mechanism to chlorantraniliprole

BACKGROUND

The rice leaffolder, Cnaphalocrocis medinalis (Guenée), has become an increasingly occurring pest in Asia in recent years. Chemical control remains the most efficient and primary tool for controlling this pest. In this study, we report the resistance status of C. medinalis in China to multiple insecticides including chlorantraniliprole and the main resistance mechanism.

RESULTS

Significant variations among field populations of C. medinalis in their resistance to 10 insecticides were observed during 2019-2022. Most of the tested field populations have developed low-to-moderate levels of resistance to abamectin (RR = 2.4-22.2), emamectin benzoate (RR = 1.9-40.3) and spinetoram (RR = 4.2-24.8). Some field populations have developed low resistance to chlorpyrifos (RR = 0.9-6.8). Indoxacarb, metaflumizone, methoxenozide and Bacillus thuringiensis (Bt) potency against all tested populations remained similar. For diamides, significantly higher levels of resistance to chlorantraniliprole (RR = 64.9-113.7) were observed in 2022, whereas all tested field populations in 2019-2021 exhibited susceptible or moderate resistance level to chlorantraniliprole (RR = 1.3-22.1). Cross-resistance between chlorantraniliprole and tetraniliprole was significant. Analysis of ryanodine receptor (RyR) mutations showed that mutation of I4712M was present in resistant populations of C. medinalis with different levels of chlorantraniliprole resistance and was the main mechanism conferring diamide resistance. Mutation of Y4621D also was detected in one tested population. Resistance management strategies for the control of C. medinalis are discussed.

CONCLUSION

C. medinalis has developed high level of resistance to chlorantraniliprole. RyR mutations were deemed as the mechanism. © 2023 Society of Chemical Industry.

c-Jun N-terminal kinase activation contributes to improving low temperature tolerance via regulating apoptosis in the Pacific white shrimp Penaeus vannamei

Temperature is an essential environmental factor for the survival of aquatic animals. Low temperature stress can induce mitochondria to produce excessive ROS and free radicals, and destroy homeostasis. c-Jun N-terminal kinase (JNK) is involved in regulating various physiological processes, including inflammatory responses, cell cycle, reproduction, and apoptosis. Here, we investigated the mechanism of ROS/JNK pathway under low temperature stress both in vitro and in vivo. In this study, transcriptome analysis revealed that apoptosis, autophagy, calcium channel, and antioxidant were involved in the mediation of low temperature tolerance in Pacific white shrimp (penaeus vannamei). PvJNK was activated in response to low temperature stress. Treatments with different temperature caused oxidative stress as demonstrated by increased intensity of the ROS indicator H2DCF-DA, and induced apoptosis as confirmed by indicator FITC. Pretreatment with N-acetylcysteine, an ROS scavenger, attenuated low temperature induced apoptosis, and inhibited the expression of PvJNK. In addition, we demonstrate that mediator PvJNK translocated to nuclear through interacting with PvRheb. By using flow cytometry, inhibiting PvJNK can increase the expression of apoptosis related genes, accelerate tissue damage, and induce ROS and cell apoptosis. The ultimate inhibition of PvJNK accelerates the mortality of shrimp under low temperature stress. Overall, these findings suggest that during low temperature stress, PvJNK was activated by ROS to regulates apoptosis via interacting with PvRheb to promote PvJNK into the nucleus and to improve low temperature tolerance of shrimp.

scRNA-seq analysis reveals toxicity mechanisms in shrimp hemocytes subjected to nitrite stress

In shrimp, hemocytes play an important role in detoxification and immune defense, and are where nitrite accumulates during exposure to this toxic environmental pollutant. However, the heterogeneity mechanisms of toxicity have not been reported under nitrite expose in shrimp. Here, we used single-cell RNA-seq to resolve 24,000 cells, which the responses of different cell populations of hemocytes under nitrite exposure in Penaeus vannamei. We identified 394 specific nitrite-responsive genes in 9 clusters of hemocytes, and found heterogeneity in the nitrite response of the three subpopulations of hemocytes (hyaline, semi-granular and granular cells). In hyaline, the response appeared modest, whereas nitrite-related dysregulation of metabolic processes in granular and semi-granular was pronounced. Ammonia nitrogen will rapidly accumulate in hemocytes of shrimp under nitrite stress. In semi-granular, excessive ammonia will interfere with oxidative phosphorylation and antioxidant system, thus inducing the production of reactive oxygen species. In granular, the abnormality of urea cycle caused by ammonia accumulation is the main toxic factor, which by inhibits arginase and arginine kinase. Collectively, our data provide a single-cell atlas for the dissection of shrimp hemocyte complexity, and reveal the toxicity mechanisms associated with nitrite exposure.

Long non-coding RNA OIP5-AS1 serves as a competing endogenous RNA to modulate X-linked inhibitor of apoptosis protein expression via adsorbing miR-429 in papillary thyroid cancer

Papillary thyroid cancer (PTC) is currently one of the most common endocrine tumors worldwide. Long non-coding RNA (LncRNA) is a vital regulator in the biological processes of diverse tumors. Hence, this work aimed to clarify the role and mechanism of lncRNA OIP5-AS1 in PTC progression. OIP5-AS1 and miR-429 expression levels in PTC tissues and cells were examined using qRT-PCR. Immunohistochemical staining (IHC) was applied to detect X-linked inhibitors of apoptosis protein (XIAP) expression in PTC tissues. A dual-luciferase reporter gene experiment was employed to validate the relationship for miR-429 and XIAP, miR-429 and OIP5-AS1. The regulatory effects of OIP5-AS1 on PTC cell proliferation, migration, and invasion was detected using the MTT, BrdU, Transwell and Western blot assays. In this work we reported that OIP5-AS1 expression was up-modulated in PTC tissues and cell lines. OIP5-AS1 overexpression enhanced the proliferation and metastasis of PTC cells, but the transfection of miR-429 mimics reversed the functions of OIP5-AS1 on the proliferation, migration, and invasion of PTC cells. Additionally, OIP5-AS1 was identified as a competitive endogenous RNA (ceRNA) that repressed miR-429, thereby increasing the expression level of XIAP. Taken together, the findings confirm that OIP5-AS1 accelerates PTC progression via modulating the miR-429/XIAP axis and imply that OIP5-AS1 is likely to be a therapeutic target for PTC.

Vitamin B6 Intake and Pancreatic Carcinoma Risk: A Meta-Analysis

Objectives: There are conflicting results for the association between vitamin B6 intake with reduced pancreatic carcinoma risk. Thus, a meta-analysis was performed to summarize the evidences from epidemiological studies. Methods: We searched documents from PubMed-Medline, Web of Science, and Cochrane Library. The results were analyzed by using Stata software. Results: A total of nine studies were included. The multivariate-adjusted results found that the total RR values of pancreatic carcinoma was 0.65 (95% CI: 0.53-0.80) for the highest vitamin B6 intake vs the lowest vitamin B6 intake, and there was no significant heterogeneity among studies (I2 = 42.0%, P = 0.087). Sensitivity analysis indicated that no single study leaded to an excessive change for the relation between vitamin B6 intake and pancreatic carcinoma risk. Conclusions: This meta-analysis suggested that vitamin B6 intake could significantly decrease pancreatic carcinoma risk. However, further study is needed based on the limitations of the current analysis.

[Lignans from flower buds of Magnolia biondii]

The present study aims to investigate the lignans from the flower buds of Magnolia biondii. The isolation and purification of the compounds were performed by column chromatographies on Diaion HP-20, silica gel, and Sephadex LH-20, combined with semi-preparative HPLC. Their structures were elucidated on the basis of spectral data and physiochemical properties. Eighteen compounds were isolated and identified as magnolin (1), epimagnolin (2), eudesmin (3), kobusin (4), aschantin (5), lirioresinol B dimethyl ether (6), pinoresinol monomethy ether (7), (+)-de-O-methylmagnolin (8), isoeucommin A (9), syringaresinol 4-O-β-D-glucopyranoside (10), phillygenin (11), lariciresinol-4'-O-β-1-D-glucoside (12), conicaoside (13), (7'S, 8'R)-dihydrodehydrodiconiferylalcohol (14), 7R*, 8S*-dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside (15), 7S, 8R-erythro-7, 9, 9'-trihydroxy-3, 3'-dimethoxy-8-O-4'-neolignan 4-O-β-D-glucopyranoside (16), 7S, 8R-erythro-4, 9, 9'-trihydroxy-3, 3'-dimethoxy-8-O-4'-neolignan-7-O-β-D-glucopyranoside (17), and (+)-isolariciresinol (18). Compounds 7-18 are isolated from this plant for the first time.

[Progress in biochemical characteristics of hemopexin and its clinical application]

Hemopexin (HPX) is a plasma protein with the strongest binding capacity to heme and widely involved in modulation of a variety of physiological and pathological processes. The main physiological function of HPX is to bind and transport free toxic heme. Recent studies indicate that HPX also plays roles of anti-oxidant, anti-apoptosis, immune regulation and organic protection. In addition, HPX participates in regulation of cell differentiation and extracellular matrix reconstruction. In recent years, a great deal of progress has been made in studies of the mechanisms of HPX protective effects and on possible clinical application. In the past few years, especially, a number of proteomic studies have demonstrated that HPX could be served as positive molecular biomarkers for cancers of lung, liver, kidney, colon, and uterine myoma as well as osteoarthritis. In this review, recent progress in the biochemical characteristics and function of HPX and its possible clinical applications are summarized.

[Feasibility of treatment of landfill leachates by external loop three phase fluidized bed-constructed wetland system]

In this study, the system composed with the external loop fluidized bed reactor and constructed wetland was used to treat the landfill leachate. The change of water quality for the landfill leachate treated by this system was investigated. The experimental results indicated that the COD and NH4(+) -N of the influent reduced from 4000 mg x L(-1) and 300 mg x L(-1) to 1 500 mg x L(-1) and 150 mg x L(-1) after the external loop three phase fluidized bed reactor and steady at 200 mg x L(-1) and 10 mg x L(-1) behind treated by the constructed wetland. The heavy metals of Cd, Zn, Pb were also reduced for treatment by external loop three phase fluidized bed reactor. They were steady at 0.01 mg x L(-1), 0.5 mg x L(-1), 0.1 mg x L(-1) from 0.12 mg x L(-1), 3.0 mg x L(-1), 1.4 mg x L(-1) because of the constructed wetland. We also compared the different plants for the efficiency, the results showed that whatever plants, there was little effects on the efficiency of the COD and NH4(+) -N, but the effect of heavy metal was markedness.