Deciphering the functional mechanism of zinc ions of PARP1 binding with single strand breaks and double strand breaks.

Poly(ADP-ribose)polymerase 1 (PARP1) is a key target for the treatment of cancer-related diseases, and plays an important role in biological processes such as DNA repair, regulating a variety of metabolic and signal transduction processes. Understanding the dynamic binding mechanisms between each domain of PARP1 and DNA is of great significance to deepen the understanding on the function of PARP1 and to facilitate the design of inhibitors. Herein, strategies such as classical molecular dynamics simulation, conformational analysis, binding free energy calculation and energy decomposition were used to shed light on the binding mechanisms of different DNA binding domains (DBDs, including ZnF1, ZnF2 and ZnF3) in PARP1 with DNA and on the influences of zinc ions on the binding process. On one hand, during binding with DNA, ZnF2 tends to expand its space to identify the DNA damage sites and ZnF1/ZnF2 recognizes the interfaces on both sides of DNA damage rather than one side during the process of DNA repair. More importantly, the stable secondary structure of L 2 of ZnF2 (PRO146 to MET153) is the key conformational change for ZnF1 and ZnF2 to recognize DNA damage. Meanwhile, ZnF3 has little effect on the binding mechanisms of PARP1. On the other hand, for the structural differences of DBD domains, zinc ions in ZnF1 and ZnF2 (Zn1 and Zn2) have an impact not only on the conformational changes of PARP1, but also on the conformational changes brought by the interaction of double strand breaks (DSB) and single strand breaks (SSB). And meanwhile, Zn3 also has little effect on ZnF3 for the system of ZnF3/DSB. The findings presented in this work deepen the understanding on the functional mechanism of PARP1 and provide a theoretical basis for further study on the interaction between different inhibitors and DBD domains to design more potential inhibitors.

Epidemiology and clinical features of maternal sepsis: A retrospective study of whole pregnancy period.

Maternal sepsis results in poor outcomes such as fetal or maternal death. The incidence and mortality rates of maternal sepsis vary in different places because of differences in economic development, race and medical conditions. Identifying the clinical features and determining possible mechanisms for avoiding morbidity and preventing poor outcomes would benefit committed patients. Therefore, this was an epidemiological study at a maternity transfer center in Southeast China that aimed to identify local disease features of maternal sepsis. To investigate the incidence and risk factors associated with maternal sepsis and its progression to severe sepsis in a large population-based birth cohort. This local epidemiological study was conducted in at a tertiary care center in Guangzhou, China, from 2015 to 2019. A total of 74,969 pregnant women experiencing childbirth were included in this study; Of these, 74 patients with maternal sepsis were diagnosed according to the sepsis criterion, and 118 patients without sepsis in the same period were selected randomly as the control group to study possible reasons for postpartum sepsis. This retrospective analysis covered the entire period from the first trimester to puerperium. Clinical data were collected using the hospital's electronic medical record system. Multivariate logistic regression was used to analyze risk factors for maternal sepsis. The incidences of maternal sepsis, the maternal mortality, and the fetal mortality were 0.099%, 0.004%, and 0.007%, respectively. Septic shock was associated with a higher severity of illness. All poor outcomes (maternal or fetal death) occurred during pregnancy. Postpartum sepsis had the longest onset period, and was associated with premature rupture of fetal membranes and preeclampsia. Sepsis is an important cause of both maternal and fetal mortality. Herein, we describe an epidemiological study that evaluated the incidence, development, and prognosis of local maternal sepsis. Furthermore, the characteristics of maternal sepsis are likely due to unknown pathological mechanisms, and patients would benefit from identifying more effective treatments for maternal sepsis.

Ethanol extract of Centella asiatica alleviated dextran sulfate sodium-induced colitis: Restoration on mucosa barrier and gut microbiota homeostasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Ulcerative colitis (UC) is a relapsing inflammatory disease that still demands for effective remedies due to various adverse effects of the current principal treatments. Centella asiatica is a traditional medical herb with long application history in anti-inflammation. AIM OF THE STUDY: To explore the anti-inflammatory effect and possible mechanism of C. asiatica ethanol extract (CA) in a murine colitis model induced by dextran sulfate sodium (DSS). MATERIALS AND METHODS: CA was analyzed by high performance liquid chromatograph (HPLC). The colitis model was induced by free access to 3% DSS in distilled water for 7 days. CA (100, 200, and 400 mg/kg) and 5-aminosalicylic acid (5-ASA, 400 mg/kg) were administrated by gavage during the 7-day DSS challenge. At the end of experiment, mice were sacrificed and the brain, colon and cecum contents were harvested for analysis. Colitis was evaluated by disease activity index (DAI), colon length and colon lesion macroscopic score with hematoxylin-eosin staining. Myeloperoxidase (MPO) activity in colon and 5-hydroxytryptamine (5-HT) in brain were determined by ELISA. Tight junction protein expressions (ZO-1, E-Cadherin, Claudin-1) and c-Kit in colon were assessed by western blot and immunohistochemistry, respectively. Microbiota of cecum content was analyzed by 16S rRNA sequencing. RESULTS: Data showed that with recovery on the colon length and histological structure, CA prominently decreased DAI and macroscopic score for lesion in the suffering mice. CA relieved the colitis by suppressing inflammatory cell infiltration with decreased MPO activity in the colon, and up-regulated the expression of tight junction protein (ZO-1, E-cadherin) to enhance the permeability of intestinal mucosa. Moreover, CA restored intestinal motility by promoting c-Kit expression in the colon and 5-HT in the brain. Moreover, CA was able to reshape the gut microbiota in the suffering mice. It increased the α-diversity and shifted the community by depleting the colitis-associated genera, Helicobacter, Jeotgalicoccus and Staphylococcus, with impact on several metabolism signaling pathways, which possibly contributes to the renovation on the impaired intestinal mucosal barrier. CONCLUSIONS: CA displayed the anti-inflammatory activity against the DSS-induced colitis, which would possibly rely on the restoration on mucosa barrier and gut microbiota homeostasis, highlights a promising application of C. asiatica in the clinical treatment of UC.

Pogostone attenuates TNF-α-induced injury in A549 cells via inhibiting NF-κB and activating Nrf2 pathways.

Pogostone (PO), a major component of Pogostemon cablin, displays potent protective effects against lipopolysaccharide-induced acute lung injury (ALI) in mice. This study aimed to investigate the protective effect of PO on TNF-α-induced cell injury in human alveolar epithelial cells in vitro and its underlying mechanism. The cell viability was measured using the MTS method. The cell apoptosis was determined using flow cytometry. The activities of reactive oxygen species (ROS) were detected using a fluorescence microscope. The pro-inflammatory cytokines and antioxidant genes were assessed using reverse transcription-polymerase chain reaction. The protein expression of Kelch-like ECH-associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha (IκBα), and nuclear factor-kappa B (NF-κB) p65 was analyzed using the Western blot analysis. PO alleviated cell apoptosis and inhibited ROS production. It alleviated TNF-α-induced cell injury, suppressed the levels of inflammatory cytokines [interleukin (IL)-6, IL-1ß, and IL-8], and enhanced the expression of antioxidant genes (quinine oxidoreductase 1, glutamate cysteine ligase catalytic subunit, heme oxygenase-1). It increased the expression of Keap1 and promoted the activation of Nrf2. However, the phosphorylation of IκBα and the nuclear expression of NF-κB p65 decreased. The anti-inflammatory and antioxidant effects of PO were abrogated following Nrf2 and NF-κB p65 knockdown. The results indicated a protective effect of PO against TNF-α-induced cell injury in A549 cells by modulating the balance between Nrf2 and NF-κB p65 signaling pathways. They verified PO as a promising anti-inflammatory adjuvant drug for treating ALI.

Prevention of UV radiation-induced cutaneous photoaging in mice by topical administration of patchouli oil.

ETHNOPHARMACOLOGICAL RELEVANCE: Pogostemon cablin has been widely used in traditional Chinese medicine for the treatment of many diseases, including skin disorders. In the skin beauty and care prescriptions, Pogostemon cablin is one of the top ten frequently used traditional Chinese medicines. AIM OF THE STUDY: The present study was aimed to investigate the protective effects of the essential oil of Pogostemon cablin (patchouli oil, PO) against UV-induced skin photoaging in mice. MATERIALS AND METHODS: To ensure the quality of PO, the chemical compositions of PO were identified, and the content of its chemical marker patchouli alcohol was determined, which was around 28.2% (g/g) in PO. During the experiment period, the dorsal depilated skin of mice was treated with PO for two hours prior to UV irradiation. Then the protective effects of PO on UV-induced skin photoaging were determined by macroscopic and histological evaluations, skin elastic test, collagen content determination and biochemical assays of malondiaidehyde (MDA) content, activities of anti-oxidative indicators including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT). RESULTS: Compared to UV exposure groups, present results showed that topical administration of PO, especially at dose of 6mg/mouse and 9mg/mouse, significantly inhibited the increase in skin wrinkle formation, alleviated the reduction in skin elasticity and increased the collagen content by about 21.9% and 26.3%, respectively. We also found that application of 6-9mg/mouse PO could not only decrease the epidermal thickness by about 32.6%, but also prevent the UV-induced disruption of collagen fibers and elastic fibers. Furthermore, the content of MDA was decreased by almost 26.5% and activities of SOD, GSH-Px and CAT were significantly up-regulated after the treatment of PO. CONCLUSION: Results of present study revealed that PO was capable of maintaining skin structural integrity caused by UV irradiation and it was useful in preventing photoaging. These protective effects of PO were possibly due to its anti-oxidative property. Therefore, we suggested that PO should be viewed as a potential therapeutic agent for preventing photoaging.

Anti-Candida albicans activity and pharmacokinetics of pogostone isolated from Pogostemonis Herba.

The present work was designed to evaluate the in vitro and in vivo anti-Candida activity of pogostone (PO), a natural product isolated from Pogostemon cablin (Blanco) Benth. PO showed potent in vitro activity against clinical Candida spp. isolates tested in this study. PO and the reference drug voriconazole (VRC) were equally effective against all the fluconazole-resistant Candida albicans strains, with MIC ranging from 3.1 µg/ml to 50 µg/ml. Besides, PO was fungicidal against all Candida isolates with MFC ranging from 50 µg/ml to 400 µg/ml. By contrast, VRC was fungistatic as it failed to elicit a fungicidal effect against the Candida spp. isolates at the highest tested concentration (400 µg/ml). Furthermore, oral and topical PO administration effectively reduced the fungal load in vagina of vulvovaginal candidiasis mouse models. Topical PO administration (1.0-4.0 mg/kg) demonstrated higher activity against the vulvovaginal candidiasis than VRC (4.0 mg/kg). The pharmacokinetics and safety profile of PO were also investigated. The pharmacokinetics assay revealed that PO was easily absorbed after oral administration in mice, which might account for its in vivo anti-Candida effect. The acute toxicity test showed that the median lethal dose of PO in mice was 355 mg/kg, which was much higher than the daily dose used for the therapeutic experiments. This study demonstrated the potential of PO as a promising candidate for the treatment of Candida infections, particularly for vulvovaginal candidiasis.