Transfer of cGAMP into Bystander Cells via LRRC8 Volume-Regulated Anion Channels Augments STING-Mediated Interferon Responses and Anti-viral Immunity.

The enzyme cyclic GMP-AMP synthase (cGAS) senses cytosolic DNA in infected and malignant cells and catalyzes the formation of 2'3'cGMP-AMP (cGAMP), which in turn triggers interferon (IFN) production via the STING pathway. Here, we examined the contribution of anion channels to cGAMP transfer and anti-viral defense. A candidate screen revealed that inhibition of volume-regulated anion channels (VRACs) increased propagation of the DNA virus HSV-1 but not the RNA virus VSV. Chemical blockade or genetic ablation of LRRC8A/SWELL1, a VRAC subunit, resulted in defective IFN responses to HSV-1. Biochemical and electrophysiological analyses revealed that LRRC8A/LRRC8E-containing VRACs transport cGAMP and cyclic dinucleotides across the plasma membrane. Enhancing VRAC activity by hypotonic cell swelling, cisplatin, GTPγS, or the cytokines TNF or interleukin-1 increased STING-dependent IFN response to extracellular but not intracellular cGAMP. Lrrc8e-/- mice exhibited impaired IFN responses and compromised immunity to HSV-1. Our findings suggest that cell-to-cell transmission of cGAMP via LRRC8/VRAC channels is central to effective anti-viral immunity.

Mechano-regulation of Peptide-MHC Class I Conformations Determines TCR Antigen Recognition.

TCRs recognize cognate pMHCs to initiate T cell signaling and adaptive immunity. Mechanical force strengthens TCR-pMHC interactions to elicit agonist-specific catch bonds to trigger TCR signaling, but the underlying dynamic structural mechanism is unclear. We combined steered molecular dynamics (SMD) simulation, single-molecule biophysical approaches, and functional assays to collectively demonstrate that mechanical force induces conformational changes in pMHCs to enhance pre-existing contacts and activates new interactions at the TCR-pMHC binding interface to resist bond dissociation under force, resulting in TCR-pMHC catch bonds and T cell activation. Intriguingly, cancer-associated somatic mutations in HLA-A2 that may restrict these conformational changes suppressed TCR-pMHC catch bonds. Structural analysis also indicated that HLA polymorphism might alter the equilibrium of these conformational changes. Our findings not only reveal critical roles of force-induced conformational changes in pMHCs for activating TCR-pMHC catch bonds but also have implications for T cell-based immunotherapy.

An inhibitory mechanism of AasS, an exogenous fatty acid scavenger: Implications for re-sensitization of FAS II antimicrobials.

Antimicrobial resistance is an ongoing "one health" challenge of global concern. The acyl-ACP synthetase (termed AasS) of the zoonotic pathogen Vibrio harveyi recycles exogenous fatty acid (eFA), bypassing the requirement of type II fatty acid synthesis (FAS II), a druggable pathway. A growing body of bacterial AasS-type isoenzymes compromises the clinical efficacy of FAS II-directed antimicrobials, like cerulenin. Very recently, an acyl adenylate mimic, C10-AMS, was proposed as a lead compound against AasS activity. However, the underlying mechanism remains poorly understood. Here we present two high-resolution cryo-EM structures of AasS liganded with C10-AMS inhibitor (2.33 Å) and C10-AMP intermediate (2.19 Å) in addition to its apo form (2.53 Å). Apart from our measurements for C10-AMS' Ki value of around 0.6 µM, structural and functional analyses explained how this inhibitor interacts with AasS enzyme. Unlike an open state of AasS, ready for C10-AMP formation, a closed conformation is trapped by the C10-AMS inhibitor. Tight binding of C10-AMS blocks fatty acyl substrate entry, and therefore inhibits AasS action. Additionally, this intermediate analog C10-AMS appears to be a mixed-type AasS inhibitor. In summary, our results provide proof of principle that inhibiting salvage of eFA by AasS reverses the FAS II bypass. This facilitates the development of next-generation of anti-bacterial therapeutics, esp. the dual therapy consisting of C10-AMS scaffold derivatives combined with certain FAS II inhibitors.

Mechanism of strand exchange from RecA-DNA synaptic and D-loop structures.

The strand-exchange reaction is central to homologous recombination. It is catalysed by the RecA family of ATPases, which form a helical filament with single-stranded DNA (ssDNA) and ATP. This filament binds to a donor double-stranded DNA (dsDNA) to form synaptic filaments, which search for homology and then catalyse the exchange of the complementary strand, forming either a new heteroduplex or-if homology is limited-a D-loop1,2. How synaptic filaments form, search for homology and catalyse strand exchange is poorly understood. Here we report the cryo-electron microscopy analysis of synaptic mini-filaments with both non-complementary and partially complementary dsDNA, and structures of RecA-D-loop complexes containing a 10- or a 12-base-pair heteroduplex. The C-terminal domain of RecA binds to dsDNA and directs it to the RecA L2 loop, which inserts into and opens up the duplex. The opening propagates through RecA sequestering the homologous strand at a secondary DNA-binding site, which frees the complementary strand to sample pairing with the ssDNA. At each RecA step, there is a roughly 20% probability that duplex opening will terminate and the as-yet-unopened dsDNA portion will bind to another C-terminal domain. Homology suppresses this process, through the cooperation of heteroduplex pairing with the binding of ssDNA to the secondary site, to extend dsDNA opening. This mechanism locally limits the length of ssDNA sampled for pairing if homology is not encountered, and could allow for the formation of multiple, widely separated synapses on the donor dsDNA, which would increase the likelihood of encountering homology. These findings provide key mechanistic insights into homologous recombination.

Structural basis for regulation of SOS response in bacteria.

In response to DNA damage, bacterial RecA protein forms filaments with the assistance of DinI protein. The RecA filaments stimulate the autocleavage of LexA, the repressor of more than 50 SOS genes, and activate the SOS response. During the late phase of SOS response, the RecA filaments stimulate the autocleavage of UmuD and λ repressor CI, leading to mutagenic repair and lytic cycle, respectively. Here, we determined the cryo-electron microscopy structures of Escherichia coli RecA filaments in complex with DinI, LexA, UmuD, and λCI by helical reconstruction. The structures reveal that LexA and UmuD dimers bind in the filament groove and cleave in an intramolecular and an intermolecular manner, respectively, while λCI binds deeply in the filament groove as a monomer. Despite their distinct folds and oligomeric states, all RecA filament binders recognize the same conserved protein features in the filament groove. The SOS response in bacteria can lead to mutagenesis and antimicrobial resistance, and our study paves the way for rational drug design targeting the bacterial SOS response.

Structural insights into Ras regulation by SIN1.

Over the years it has been established that SIN1, a key component of mTORC2, could interact with Ras family small GTPases through its Ras-binding domain (RBD). The physical association of Ras and SIN1/mTORC2 could potentially affect both mTORC2 and Ras-ERK pathways. To decipher the precise molecular mechanism of this interaction, we determined the high-resolution structures of HRas/KRas-SIN1 RBD complexes, showing the detailed interaction interface. Mutation of critical interface residues abolished Ras-SIN1 interaction and in SIN1 knockout cells we demonstrated that Ras-SIN1 association promotes SGK1 activity but inhibits insulin-induced ERK activation. With structural comparison and competition fluorescence resonance energy transfer (FRET) assays we showed that HRas-SIN1 RBD association is much weaker than HRas-Raf1 RBD but is slightly stronger than HRas-PI3K RBD interaction, providing a possible explanation for the different outcome of insulin or EGF stimulation. We also found that SIN1 isoform lacking the PH domain binds stronger to Ras than other longer isoforms and the PH domain appears to have an inhibitory effect on Ras-SIN1 binding. In addition, we uncovered a Ras dimerization interface that could be critical for Ras oligomerization. Our results advance our understanding of Ras-SIN1 association and crosstalk between growth factor-stimulated pathways.

Transcription factor EB coordinates environmental cues to regulate T regulatory cells' mitochondrial fitness and function.

T regulatory (Treg) cells are essential for self-tolerance whereas they are detrimental for dampening the host anti-tumor immunity. How Treg cells adapt to environmental signals to orchestrate their homeostasis and functions remains poorly understood. Here, we identified that transcription factor EB (TFEB) is induced by host nutrition deprivation or interleukin (IL)-2 in CD4+ T cells. The loss of TFEB in Treg cells leads to reduced Treg accumulation and impaired Treg function in mouse models of cancer and autoimmune disease. TFEB intrinsically regulates genes involved in Treg cell differentiation and mitochondria function while it suppresses expression of proinflammatory cytokines independently of its established roles in autophagy. This coordinated action is required for mitochondria integrity and appropriate lipid metabolism in Treg cells. These findings identify TFEB as a critical regulator for orchestrating Treg generation and function, which may contribute to the adaptive responses of T cells to local environmental cues.

Novel Hemodynamic, Vascular Lesion and Cytokine/Chemokine Differences Regarding Sex in a PAH Model.

Sex differences are recognized in pulmonary hypertension, however the progression of disease with regards to vascular lesion formation and circulating cytokines/chemokines is unknown. To determine whether vascular lesion formation, changes in hemodynamics and alterations in circulating chemokines/cytokines differ between male and female. We used a progressive model of PAH, SU/Hx and analyzed cohorts of male and female rats at timepoints suggested to indicate worsening disease. Our analysis included echocardiograpy for hemodynamics, morphometry, immunofluoresecence and chemokine/cytokine analysis of plasma at each time point in both sexes. We found that male rats had significantly increased Fulton index compared to females at each time point as well as increased medial artery thickening at 8-weeks PAH. Further, females exhibit fewer obliterative vascular lesions than males at our latest time point. Our data also show increased IL-4, GM-CSF, IL-10, and MIP-1 that are not observed in females, while females have increased RANTES and CXCL-10 not found in males. Males also have increased infiltrating macrophages in vascular lesions as compared to females. We found that development of progressive PAH in hemodynamics, morphology and chemokine/cytokine circulation differ significantly between males and females. These data suggest a macrophage driven pathology in males, while there may be T-cell protection from vascular damage in female PAH.

Asperosaponin VI facilitates the regeneration of skeletal muscle injury by suppressing GSK-3ß-mediated cell apoptosis.

Asperosaponin VI (ASA VI) is a bioactive triterpenoid saponin extracted from Diptychus roots, of Diptyl, and has previously shown protective functions in rheumatoid arthritis and sepsis. This study investigates the effects and molecular mechanisms of ASA VI on skeletal muscle regeneration in a cardiotoxin (CTX)-induced skeletal muscle injury mouse model. Mice were subjected to CTX-induced injury in the tibialis anterior and C2C12 myotubes were treated with CTX. Muscle fiber histology was analyzed at 7 and 14 days postinjury. Apoptosis and autophagy-related protein expression were evaluated t s by Western blot, and muscle regeneration markers were quantified by quantitative polymerase chain reaction. Docking studies, cell viability assessments, and glycogen synthase kinase-3ß (GSK-3ß) activation analyses were performed to elucidate the mechanism. ASA VI was observed to improve muscle interstitial fibrosis, remodeling, and performance in CTX-treated mice, thereby increased skeletal muscle size, weight, and locomotion. Furthermore, ASA VI modulated the expression of apoptosis and autophagy-related proteins through GSK-3ß inhibition and activated the transcription of regeneration genes. Our results suggest that ASA VI mitigates skeletal muscle injury by modulating apoptosis and autophagy via GSK-3ß signaling and promotes regeneration, thus presenting a probable therapeutic agent for skeletal muscle injury.

Performance of large language models on benign prostatic hyperplasia frequently asked questions.

BACKGROUND: Benign prostatic hyperplasia (BPH) is a common condition, yet it is challenging for the average BPH patient to find credible and accurate information about BPH. Our goal is to evaluate and compare the accuracy and reproducibility of large language models (LLMs), including ChatGPT-3.5, ChatGPT-4, and the New Bing Chat in responding to a BPH frequently asked questions (FAQs) questionnaire. METHODS: A total of 45 questions related to BPH were categorized into basic and professional knowledge. Three LLM-ChatGPT-3.5, ChatGPT-4, and New Bing Chat-were utilized to generate responses to these questions. Responses were graded as comprehensive, correct but inadequate, mixed with incorrect/outdated data, or completely incorrect. Reproducibility was assessed by generating two responses for each question. All responses were reviewed and judged by experienced urologists. RESULTS: All three LLMs exhibited high accuracy in generating responses to questions, with accuracy rates ranging from 86.7% to 100%. However, there was no statistically significant difference in response accuracy among the three (p > 0.017 for all comparisons). Additionally, the accuracy of the LLMs' responses to the basic knowledge questions was roughly equivalent to that of the specialized knowledge questions, showing a difference of less than 3.5% (GPT-3.5: 90% vs. 86.7%; GPT-4: 96.7% vs. 95.6%; New Bing: 96.7% vs. 93.3%). Furthermore, all three LLMs demonstrated high reproducibility, with rates ranging from 93.3% to 97.8%. CONCLUSIONS: ChatGPT-3.5, ChatGPT-4, and New Bing Chat offer accurate and reproducible responses to BPH-related questions, establishing them as valuable resources for enhancing health literacy and supporting BPH patients in conjunction with healthcare professionals.

Relationship of serum 25-hydroxyvitamin D, obesity with new-onset obstructive sleep apnea.

OBJECTIVE: The prospective association between vitamin D and obstructive sleep apnea (OSA) remains uncertain. We aimed to assess the association between serum 25-hydroxyvitamin D (25(OH)D), a major circulating form of vitamin D, and new-onset OSA, and examine the modifying effect of obesity. MATERIALS AND METHODS: This prospective cohort study included 444,975 participants from UK Biobank without prior OSA. The primary outcome was new-onset OSA. RESULTS: During a median follow-up duration of 12.0 years, 6051 (1.4%) participants occurred new-onset OSA. Overall, there was an inverse relation of serum 25(OH)D concentrations with the risk of new-onset OSA (per SD increment, HR, 0.92; 95%CI: 0.89-0.95). In the analysis of the interactions of serum 25(OH)D with the combination of BMI (<25, 25- < 30, and ≥30 kg/m2) and waist circumference (WC) (<90 and ≥90 cm) categories on new-onset OSA, the significantly inverse association of serum 25(OH)D and new-onset OSA was mainly found in participants with both BMI ≥ 25 kg/m2 and WC ≥ 90 cm (BMI 25-30 kg/m2 and WC ≥ 90 cm: per SD increment, HR, 0.90; 95%CI: 0.84-0.95; BMI ≥ 30 kg/m2 and WC ≥ 90 cm: per SD increment, HR, 0.85; 95%CI: 0.81-0.88), but not in other four groups with BMI < 25 kg/m2 or WC < 90 cm (P -interaction = 0.004). CONCLUSIONS: There was an inverse relation of serum 25(OH)D with the risk of new-onset OSA in participants with both BMI ≥ 25 kg/m2 and WC ≥ 90 cm. Our findings suggest the importance of maintaining a higher serum 25(OH)D concentration for primary prevention of OSA in a population with obesity.

Infection promotes Ser-214 phosphorylation important for generation of cytotoxic tau variants.

Patients who recover from hospital-acquired pneumonia exhibit a high incidence of end-organ dysfunction following hospital discharge, including cognitive deficits. We have previously demonstrated that pneumonia induces the production and release of cytotoxic oligomeric tau from pulmonary endothelial cells, and these tau oligomers can enter the circulation and may be a cause of long-term morbidities. Endothelial-derived oligomeric tau is hyperphosphorylated during infection. The purpose of these studies was to determine whether Ser-214 phosphorylation of tau is a necessary stimulus for generation of cytotoxic tau variants. The results of these studies demonstrate that Ser-214 phosphorylation is critical for the cytotoxic properties of infection-induced oligomeric tau. In the lung, Ser-214 phosphorylated tau contributes to disruption of the alveolar-capillary barrier, resulting in increased permeability. However, in the brain, both the Ser-214 phosphorylated tau and the mutant Ser-214-Ala tau, which cannot be phosphorylated, disrupted hippocampal long-term potentiation suggesting that inhibition of long-term potentiation was relatively insensitive to the phosphorylation status of Ser-214. Nonetheless, phosphorylation of tau is essential to its cytotoxicity since global dephosphorylation of the infection-induced cytotoxic tau variants rescued long-term potentiation. Collectively, these data demonstrate that multiple forms of oligomeric tau are generated during infectious pneumonia, with different forms of oligomeric tau being responsible for dysfunction of distinct end-organs during pneumonia.

Tunable Colloidal Properties of Lauramidopropyl Betaine and Li Co-modified Montmorillonite in Ethanol/Water.

Montmorillonite (Mt) is a hydrophilic clay mineral with a generally high cationic exchange capacity and a remarkable swellability in water. Yet the application of Mt in cosmetics, paints, polymer nanocomposites, drug delivery systems, and tissue engineering are limited due to its unfavorable swelling and dispersion in alcohol/water mixtures. Improving the swellability and dispersibility of Mt in mixtures of ethanol and water remains challenging. Here, we showed that the swellability and dispersibility of Mt in ethanol/water could be significantly enhanced when lithium-Mt (Li-Mt) was intercalated by zwitterionic surfactant lauramidopropyl betaine (LPB). The binding mechanism of the LPB intercalate to Li-Mt originated from a combination of van der Waals forces, ion-dipole interaction, and electrostatic attraction. Due to the synergistic effect of Li+ and LPB, the comodified Mt (LPB-Li-Mt) exhibited excellent swellability, dispersibility, and rheological properties. The structure, morphology, zeta potential, dispersibility, and gel-forming performance of LPB-Li-Mt can be modulated by the concentrations of ethanol in ethanol/water mixtures. When the ethanol concentration increased to 75% v/v ethanol solution, the free swelling of LPB-Li-Mt remained above 80%. The results from X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray photoemission spectrometry, and small-angle X-ray scattering confirmed the full exfoliation of LPB-Li-Mt at 75% (v/v) ethanol solution. The formation of a stable colloidal LPB-Li-Mt dispersion in a mixture of ethanol/water might be derived from the association between water molecules and the Li+, the hydrophobic interaction, and the ion-dipole of ethanol with the LPB molecules. The findings provide a guide for improving dispersion and swelling of Mt and modified ones in water-miscible organic solvents.

Saliva-based detection of SARS-CoV-2: a bibliometric analysis of global research.

Saliva has emerged as a promising noninvasive biofluid for the diagnosis of oral and systemic diseases, including viral infections. During the coronavirus disease 2019 (COVID-19) pandemic, a growing number of studies focused on saliva-based detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Taking advantage of the WoS core collection (WoSCC) and CiteSpace, we retrieved 1021 articles related to saliva-based detection of SARS-CoV-2 and conducted a comprehensive bibliometric analysis. We analyzed countries, institutions, authors, cited authors, and cited journals to summarize their contribution and influence and analyzed keywords to explore research hotspots and trends. From 2020 to 2021, research focused on viral transmission via saliva and verification of saliva as a reliable specimen, whereas from 2021 to the present, the focus of research has switched to saliva-based biosensors for SARS-CoV-2 detection. By far, saliva has been verified as a reliable specimen for SARS-CoV-2 detection, although a standardized procedure for saliva sampling and processing is needed. Studies on saliva-based detection of SARS-CoV-2 will promote the development of saliva-based diagnostics and biosensors for viral detection. Collectively, our findings could provide valuable information to help scientists perceive the basic knowledge landscapes on saliva-based detection of SARS-CoV-2, the past and current research hotspots, and future opportunities.

Association between longitudinal changes in body composition and the risk of kidney outcomes in participants with overweight/obesity and type 2 diabetes mellitus.

AIMS: To assess the relationship of longitudinal changes in fat mass (FM), lean mass (LM) and waist circumference (WC) with incident kidney outcomes in people with overweight/obesity and type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: A total of 3927 participants with baseline estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 from the Look AHEAD (Action for Health in Diabetes) trial were included. The primary outcome was kidney outcomes, defined as a decrease in eGFR of at least 40% from baseline at follow-up visit, or end-stage kidney disease. RESULTS: During a median follow-up of 8.0 years, 450 kidney outcomes were documented after the first 1 year. In the intensive lifestyle intervention (ILI) group, reductions in FM (per 10% decrease, adjusted hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.69-0.94) and WC (per 10% decrease, adjusted HR 0.72, 95% CI 0.59-0.88) from baseline to 1-year follow-up were significantly associated with a lower risk of kidney outcomes. The change in LM was not significantly associated with risk of kidney outcomes (per 10% decrease, adjusted HR 0.78, 95% CI 0.58-1.06). In the diabetes support and education group (control group), no significant association was found between changes in body composition and kidney outcomes. Similar results were observed for the 4-year changes in body composition. CONCLUSIONS: In this post hoc analysis of the Look AHEAD trial, longitudinal declines in FM and WC were associated with a lower risk of kidney outcomes in the ILI group in participants with overweight/obesity and T2DM.

Evaluation of models to predict prognosis in patients with advanced hepatocellular carcinoma treated with TACE combined with apatinib.

BACKGROUND: The HAP, Six-and-Twelve, Up to Seven, and ALBI scores have been substantiated as reliable prognostic markers in patients presenting with intermediate and advanced hepatocellular carcinoma (HCC) undergoing transarterial chemoembolization (TACE) treatment. Given this premise, our research aims to assess the predictive efficacy of these models in patients with intermediate and advanced HCC receiving a combination of TACE and Apatinib. Additionally, we have conducted a meticulous comparative analysis of these four scoring systems to discern their respective predictive capacities and efficacies in combined therapy. METHODS: Performing a retrospective analysis on the clinical data from 200 patients with intermediate and advanced HCC, we studied those who received TACE combined with Apatinib at the First Affiliated Hospital of the University of Science and Technology of China between June 2018 and December 2022. To identify the factors affecting survival, the study performed univariate and multivariate Cox regression analyses, with calculations of four different scores: HAP, Six-and-Twelve, Up to Seven, and ALBI. Lastly, Harrell's C-index was employed to compare the prognostic abilities of these scores. RESULTS: Cox proportional hazards model results revealed that the ALBI score, presence of portal vein tumor thrombus (PVTT, )and tumor size are independent determinants of prognostic survival. The Kaplan-Meier analyses showed significant differences in survival rates among patients classified by the HAP, Six-and-Twelve, Up to Seven, and ALBI scoring methods. Of the evaluated systems, the HAP scoring demonstrated greater prognostic precision, with a Harrell's C-index of 0.742, surpassing the alternative models (P < 0.05). In addition, an analysis of the area under the AU-ROC curve confirms the remarkable superiority of the HAP score in predicting short-term survival outcomes. CONCLUSION: Our study confirms the predictive value of HAP, Six-and-Twelve, Up to Seven, and ALBI scores in intermediate to advanced Hepatocellular Carcinoma (HCC) patients receiving combined Transarterial Chemoembolization (TACE) and Apatinib therapy. Notably, the HAP model excels in predicting outcomes for this specific HCC subgroup.

Effects of Semaphorin3A on the growth of sensory and motor neurons.

After peripheral nerve injury, motor and sensory axons can regenerate, but the inaccurate reinnervation of the target leads to poor functional recovery. Schwann cells (SCs) express sensory and motor phenotypes associated with selective regeneration. Semaphorin 3A (Sema3A) is an axonal chemorepellent that plays an essential role in axon growth. SCs can secret Sema3A, and Sema3A presents a different expression pattern at the proximal and distal ends of injured sensory and motor nerves. Hence, in our study, the protein expression and secretion of Sema3A in sensory and motor SCs and the expression of its receptor Neuropilin-1 (Nrp1) in dorsal root ganglia (DRG) sensory neurons (SNs) and spinal cord motor neurons (MNs) were detected by Western blot and ELISA. The effect of Sema3A at different concentrations on neurite growth of sensory and motor neurons was observed by immunostaining. Also, by blocking the Nrp1 receptor on neurons, the effect of Sema3A on neurite growth was observed. Finally, we observed the neurite growth of sensory and motor neurons cocultured with Sema3A siRNA transfected SCs by immunostaining. The results suggested that the expression and secretion of Sema3A in sensory SCs are more significant than that in motor SCs, and the expression of its receptor Nrp1 in SNs is higher than in MNs. Sema3A could inhibit the neurite growth of sensory and motor neurons via Nrp1, and Sema3A has a more substantial effect on the neurite growth of SNs. These data provide evidence that SC-secreted Sema3A might play a role in selective regeneration by a preferential effect on SNs.

α4 nicotinic receptors on GABAergic neurons mediate a cholinergic analgesic circuit in the substantia nigra pars reticulata.

Nicotinic acetylcholine receptors (nAChRs) regulate pain pathways with various outcomes depending on receptor subtypes, neuron types, and locations. But it remains unknown whether α4ß2 nAChRs abundantly expressed in the substantia nigra pars reticulata (SNr) have potential to mitigate hyperalgesia in pain states. We observed that injection of nAChR antagonists into the SNr reduced pain thresholds in naïve mice, whereas injection of nAChR agonists into the SNr relieved hyperalgesia in mice, subjected to capsaicin injection into the lower hind leg, spinal nerve injury, chronic constriction injury, or chronic nicotine exposure. The analgesic effects of nAChR agonists were mimicked by optogenetic stimulation of cholinergic inputs from the pedunculopontine nucleus (PPN) to the SNr, but attenuated upon downregulation of α4 nAChRs on SNr GABAergic neurons and injection of dihydro-ß-erythroidine into the SNr. Chronic nicotine-induced hyperalgesia depended on α4 nAChRs in SNr GABAergic neurons and was associated with the reduction of ACh release in the SNr. Either activation of α4 nAChRs in the SNr or optogenetic stimulation of the PPN-SNr cholinergic projection mitigated chronic nicotine-induced hyperalgesia. Interestingly, mechanical stimulation-induced ACh release was significantly attenuated in mice subjected to either capsaicin injection into the lower hind leg or SNI. These results suggest that α4 nAChRs on GABAergic neurons mediate a cholinergic analgesic circuit in the SNr, and these receptors may be effective therapeutic targets to relieve hyperalgesia in acute and chronic pain, and chronic nicotine exposure.

L-shaped association between dietary zinc intake and cognitive decline in Chinese older people.

BACKGROUND AND OBJECTIVE: The prospective association between dietary zinc (Zn) intake and cognitive decline remains uncertain. We aimed to assess the relationship of dietary Zn intake with the risk of cognitive decline in the Chinese older people, and examine the possible effect modifiers on this association. METHODS: A total of 3,106 older Chinese adults aged 55 years or older from China Health and Nutrition Survey were included. Dietary nutrients intake information was collected by combined 24-h dietary recalls with weighing food inventory. The cognitive decline was defined as the 5-year decline rate in global and composite cognitive scores, based on a subset of items from the Telephone Interview for Cognitive Status-modified. RESULTS: The median follow-up duration was 5.9 years. There was an L-shaped association between dietary Zn intake and the 5-year decline rates in global and composite cognitive scores, with an inflection point at 8.8 mg/day of dietary Zn. For the composite cognitive scores, compared with the first quantile (<7.9 mg/day) of dietary Zn intake, quantiles 2-6 (≥7.9 mg/day) had a significantly slower cognitive decline rate (ß: -0.24; 95% confidence interval: -0.40 to -0.07). Similar results were found for the global cognitive scores. Moreover, the inverse association between dietary Zn intake and cognitive decline in composite cognitive scores was significantly stronger in those with lower levels of physical activity (P-interactions = 0.041). CONCLUSION: Dietary Zn intake was negatively associated with cognitive decline in the older people. Maintaining appropriate dietary Zn levels may prevent cognitive decline.

Association between lung function and risk of microvascular diseases in patients with diabetes: A prospective cohort and Mendelian randomization study.

BACKGROUND AND AIMS: To investigate causal relationships of lung function with risks microvascular diseases among participants with diabetes, type 2 diabetes mellitus (T2DM) and type 1 diabetes mellitus (T1DM), respectively, in prospective and Mendelian randomization (MR) study. METHODS AND RESULTS: 14,617 participants with diabetes and without microvascular diseases at baseline from the UK Biobank were included in the prospective analysis. Of these, 13,421 had T2DM and 1196 had T1DM. The linear MR analyses were conducted in the UK Biobank with 6838 cases of microvascular diseases and 10,755 controls. Lung function measurements included forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). The study outcome was microvascular diseases, a composite outcome including chronic kidney diseases, retinopathy and peripheral neuropathy. During a median follow-up of 12.1 years, 2668 new-onset microvascular diseases were recorded. FVC (%predicted) was inversely associated with the risk of new-onset microvascular diseases in participants with diabetes (Per SD increment, adjusted HR = 0.86; 95%CI:0.83-0.89), T2DM (Per SD increment, adjusted HR = 0.86; 95%CI:0.82-0.90) and T1DM (Per SD increment, adjusted HR = 0.87; 95%CI: 0.79-0.97), respectively. Similar results were found for FEV1 (%predicted). In MR analyses, genetically predicted FVC (adjusted RR = 0.55, 95%CI:0.39-0.77) and FEV1 (adjusted RR = 0.48, 95%CI:0.28-0.83) were both inversely associated with microvascular diseases in participants with T1DM. No significant association was found in those with T2DM. Similar findings were found for each component of microvascular diseases. CONCLUSION: There was a causal inverse association between lung function and risks of microvascular diseases in participants with T1DM, but not in those with T2DM.