TMEM16 and TMEM63/OSCA proteins share a conserved potential to permeate ions and phospholipids.

The calcium-activated TMEM16 proteins and the mechanosensitive/osmolarity-activated OSCA/TMEM63 proteins belong to the Transmembrane Channel/Scramblase (TCS) superfamily. Within the superfamily, OSCA/TMEM63 proteins, as well as TMEM16A and TMEM16B, likely function solely as ion channels. However, the remaining TMEM16 members, including TMEM16F, maintain an additional function as scramblases, rapidly exchanging phospholipids between leaflets of the membrane. Although recent studies have advanced our understanding of TCS structure-function relationships, the molecular determinants of TCS ion and lipid permeation remain unclear. Here we show that single lysine mutations in transmembrane helix (TM) 4 allow non-scrambling TCS members to permeate phospholipids. This study highlights the key role of TM 4 in controlling TCS ion and lipid permeation and offers novel insights into the evolution of the TCS superfamily, suggesting that, like TMEM16s, the OSCA/TMEM63 family maintains a conserved potential to permeate ions and phospholipids.

[Establishment and preliminary application of organoids in ovarian cancer].

Objective: To explore the establishment and application of ovarian cancer organoids. Methods: Fresh ovarian tumor tissues, obtaining from patients underwent surgery in the First Affiliated Hospital of Nanjing Medical University between October 2021 and March 2022, were collected, enzymatic degraded, digested, and embedded into matrigel to establish organoids. A total of 32 ovarian cancer samples were collected. Hematoxylin eosin (HE) staining and immunofluorescence (IF) procedure were used to verify the morphological structure of organoids and their expression of molecular markers. 3D cyto-live or dead assay was used to detecte the live or dead cells in organoids. Carboplatin with a concentration ranging from 5 to 80 µmol/L (5, 10, 20, 40, 80 µmol/L) was added to organoids to calculate the 50% inhibitory concentration (IC50) in different organoids. Results: (1) Organoids from a total of 32 patients were established, of which 18 cases could be passaged stably in the long term in vitro, while 14 could be passaged in the short time. The average amplification time of long-term passage in vitro was over 3 months, and the longest reached 9 months. (2) In HE staining, significant nuclei atypia and local micropapillary structures were observed in organoids. IF staining revealed that ovarian cancer organoids expressed molecular markers similar to primary tumor tissues, such as Pan cytokeratin (Pan-CK), p53, paired box gene 8 (PAX8), and Wilms tumor gene 1 (WT1). (3) In 3D cyto-live or dead assay, a large number of apoptotic cells were observed inside and around the organoids after added carboplatin. The sensitivity to carboplatin varied in 18 organoids could amplify in the long term, with an average IC50 of (29.5±15.8) µmol/L. Moreover, IC50 values of 4 organoids derived from patients received neoadjuvant chemotherapy were much higher than the 14 organoids which did not received neoadjuvant chemotherapy [(48.7±11.3) µmol/L vs (24.0±12.1) µmol/L; t=3.429, P=0.022]. Conclusions: Organoids recapitulate ovarian cancers in vitro and could be stably passaged. Organoids derived from patients received neoadjuvant chemotherapy have higher resistance to carboplatin.

DIXDC1 prevents oxygen-glucose deprivation/reoxygenation-induced injury in hippocampal neurons in vitro by promoting Wnt/ß-catenin signaling.

OBJECTIVE: Dishevelled-Axin (DIX) domain containing 1 (DIXDC1), a novel DIX domain-containing protein and a positive regulator of Wingless (Wnt) signaling, has previously been reported to play multiple roles in neurodevelopment and neurological disorders. However, whether DIXDC1 plays a role during cerebral ischemia/reperfusion injury remains unknown. In this study, we investigated the potential role of DIXDC1 in neuronal injury induced by oxygen-glucose deprivation and reoxygenation (OGD/R), an in vitro model of cerebral ischemia/reperfusion injury. MATERIALS AND METHODS: Neuronal injury was induced by OGD/R treatment. Relative mRNA expression of DIXDC1 was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Protein expression of DIXDC1 and ß-catenin was determined by Western blot. Cell viability was examined by the cell counting kit-8 assay. Cell cytotoxicity was detected by the lactate dehydrogenase assay. Cell apoptosis was detected by the caspase-3 activity assay. The activity of Wnt/ß-catenin signaling was detected by the luciferase reporter assay. RESULTS: TWe found that DIXDC1 expression was significantly upregulated in hippocampal neurons following OGD/R treatment. Small interfering RNA-mediated silencing of DIXDC1 significantly impaired viability and promoted cell injury and apoptosis in neurons with OGD/R treatment. In contrast, overexpression of DIXDC1 increased the viability and reduced cell injury and apoptosis in neurons with OGD/R treatment, showing protective effects against OGD/R injury. Furthermore, our results showed that DIXDC1 promoted the expression of ß-catenin and activation of Wnt signaling. Notably, inhibition of Wnt signaling significantly abrogated DIXDC-mediated neuroprotective effects. CONCLUSIONS: Our results demonstrate that DIXDC1 prevents OGD/R-induced neuronal injury by promoting Wnt/ß-catenin signaling. Our study indicates that DIXDC1 may play an important role in cerebral ischemia and reperfusion serving as a potential target for the treatment of cerebral ischemia/reperfusion injury.

P1 Ref Endonuclease: A Molecular Mechanism for Phage-Enhanced Antibiotic Lethality.

Ref is an HNH superfamily endonuclease that only cleaves DNA to which RecA protein is bound. The enigmatic physiological function of this unusual enzyme is defined here. Lysogenization by bacteriophage P1 renders E. coli more sensitive to the DNA-damaging antibiotic ciprofloxacin, an example of a phenomenon termed phage-antibiotic synergy (PAS). The complementary effect of phage P1 is uniquely traced to the P1-encoded gene ref. Ref is a P1 function that amplifies the lytic cycle under conditions when the bacterial SOS response is induced due to DNA damage. The effect of Ref is multifaceted. DNA binding by Ref interferes with normal DNA metabolism, and the nuclease activity of Ref enhances genome degradation. Ref also inhibits cell division independently of the SOS response. Ref gene expression is toxic to E. coli in the absence of other P1 functions, both alone and in combination with antibiotics. The RecA proteins of human pathogens Neisseria gonorrhoeae and Staphylococcus aureus serve as cofactors for Ref-mediated DNA cleavage. Ref is especially toxic during the bacterial SOS response and the limited growth of stationary phase cultures, targeting aspects of bacterial physiology that are closely associated with the development of bacterial pathogen persistence.

EFFECT OF PREGNANE XENOBIOTIC RECEPTOR ACTIVATION ON INFLAMMATORY BOWEL DISEASE TREATED WITH RIFAXIMIN.

The causes and pathogenesis of Inflammatory Bowel Disease (IBD) are still not clearly understood. This study aims to prove the important role of rifaximin played in inflammatory reaction caused by abnormity of the intestinal mucosal immune system. Intestinal microflora can greatly promote and maintain the inflammatory reaction of IBD, therefore, antibiotics can be used to treat IBD. Rifaximin is a medicine usually used for local intestinal infection. Many clinical and basic studies have shown that both a single application of rifaximin and the joint application with other medicines could achieve a good efficacy. This paper studied the activation of Pregnane Xenobiotic Receptor (PXR) in treating IBD with rifaximin and analyzed its efficacy in IBD when PXR was involved in the transport of medicine and metabolism. The results prove that rifaximin can not only serve as an anti-microbial drug, but can activate PXR and actually weaken the reaction of IBD. Thus it is safe to say that rifaximin has great potential in treating IBD.

Achievement of equity and universal access in China's health service: a commentary on the historical reform perspective from the UK National Health Service.

This paper aims to examine the UK National Health Service (NHS) in the historical context of its background reforms and to investigate future developmental strategies for China's health system. We focus on the central issues facing China's future healthcare development: equity and access. China and the UK have approached healthcare reform from opposite perspectives, the NHS has maintained the core principle of providing universal health coverage throughout the decades. However, due to increasing demand, reforms to improve and sustain efficiency have meant increasing government funding while introducing elements of a market system. Conversely, China has moved from a centrally planned system to a fee-for-service system, but serious problems of inequity and access call for new methods of organisation and financing. With the future of both systems under constant debate, international experience will play a vital role in formulating health system reform strategies.

Expression of B-type endothelin receptor gene during neural development.

Mutations of the B-type endothelin receptor (ETRB) gene have been found to cause defects in the development of enteric neurons, which resulted in aganglionic megacolon in rodents and humans. To determine the distribution of ETRB mRNA during neural development, mainly in the CNS, in situ hybridization was applied at various developmental stages of rat. ETRB gene was abundantly expressed prenatally in the ventricular and subventricular zones, as well as postnatally in the ependymal and subependymal cells. ETRB mRNA was also strongly detected prenatally in the dorsal root ganglia, as well as postnatally in the cerebellar Bergmann glial cells and epithelial cells of choroid plexus. Our data suggest that ETRB acts as a regulator in the differentiation, proliferation, or migration of neural cells during development.

A comparative study of first and third year student nurses' knowledge and attitudes on the elderly and ageing.

A comparative study was carried out to assess Year I and Year III student nurses' attitudes and knowledge of the elderly. Significantly more Year I students disagreed that the elderly had a capacity to learn (chi 2 = 11.08, p = 0.0006). Year III students were significantly more likely to obtain information about the elderly from the mass media, agencies, and relatives but not from health personnel. Nearly all respondents (96.25%) in the study wanted to know more about the elderly. Only 3 of the 14 questions on ageing revealed significant differences in knowledge between the two groups. The basic course in gerontology should be expanded and revised to dispel erroneous attitudes, allow better understanding of the ageing process, and ensure entry-level competence in caring for older people.

Absence of 4,977-bp deletion of blood cell mitochondrial DNA in patients with young-onset Parkinson's disease.

Decreased mitochondrial Complex I activities and a 4,977-bp deletion in mitochondrial DNA (mtDNA) have been reported in patients with Parkinson's disease. Based on the assumption of possible links between this 4,977-bp deletion and the etiology of Parkinson's disease, we analyzed mtDNA of blood cells from 15 patients with young-onset Parkinson's disease after the DNA was amplified by polymerase chain reaction. We could not detect the 4,977-bp mtDNA deletion in any of these patients. This result suggests that Parkinson's disease is not a mitochondrial disease due to the 4,977-bp mtDNA deletion. The 4,977-bp deletion in mtDNA appears to be an age-related phenomenon.