Molecular details of ruthenium red pore block in TRPV channels.

Transient receptor potential vanilloid (TRPV) channels play a critical role in calcium homeostasis, pain sensation, immunological response, and cancer progression. TRPV channels are blocked by ruthenium red (RR), a universal pore blocker for a wide array of cation channels. Here we use cryo-electron microscopy to reveal the molecular details of RR block in TRPV2 and TRPV5, members of the two TRPV subfamilies. In TRPV2 activated by 2-aminoethoxydiphenyl borate, RR is tightly coordinated in the open selectivity filter, blocking ion flow and preventing channel inactivation. In TRPV5 activated by phosphatidylinositol 4,5-bisphosphate, RR blocks the selectivity filter and closes the lower gate through an interaction with polar residues in the pore vestibule. Together, our results provide a detailed understanding of TRPV subfamily pore block, the dynamic nature of the selectivity filter and allosteric communication between the selectivity filter and lower gate.

Serotonin modulates melatonin synthesis as an autocrine neurotransmitter in the pineal gland.

The pineal gland secretes melatonin principally at night. Regulated by norepinephrine released from sympathetic nerve terminals, adrenergic receptors on pinealocytes activate aralkylamine N-acetyltransferase that converts 5-hydroxytryptamine (5-HT, serotonin) to N-acetylserotonin, the precursor of melatonin. Previous studies from our group and others reveal significant constitutive secretion of 5-HT from pinealocytes. Here, using mass spectrometry, we demonstrated that the 5-HT is secreted primarily via a decynium-22-sensitive equilibrative plasma membrane monoamine transporter instead of by typical exocytotic quantal secretion. Activation of the endogenous 5-HT receptors on pinealocytes evoked an intracellular Ca2+ rise that was blocked by RS-102221, an antagonist of 5-HT2C receptors. Applied 5-HT did not evoke melatonin secretion by itself, but it did potentiate melatonin secretion evoked by submaximal norepinephrine. In addition, RS-102221 reduced the norepinephrine-induced melatonin secretion in strips of pineal gland, even when no exogenous 5-HT was added, suggesting that the 5-HT that is constitutively released from pinealocytes accumulates enough in the tissue to act as an autocrine feedback signal sensitizing melatonin release.

Psychosociocultural correlates of mental health among Mexican American students in a Hispanic-serving institution: A conditional process analysis.

In this study, we used a psychosociocultural framework to examine whether cultural congruity was related to mental health indirectly via a sense of university belonging in a sample of 322 Mexican American undergraduates attending a Hispanic-serving institution (HSI). In line with literature on biculturalism and cultural values, we also examined whether Mexican American HSI students' adherence to the ethnic value of familismo and to White ethnoracial values jointly moderated this indirect association. Results of conditional process modeling indicated that greater cultural congruity was partially indirectly associated with greater university belonging, which, in turn, was associated with better mental health. This partial indirect effect was more pronounced among Mexican American students with higher levels of White ethnoracial values and weaker or nonsignificant among students with average or lower levels of these values, a moderation effect that persisted even at varying levels of familismo. Overall, our findings highlight the importance of examining the complex and interlocking associations among cultural congruity, university belonging, cultural values, and mental health for Mexican American students in an HSI context. Implications for theory, research, and practice are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reconstruction of soft tissue defect around knee with thoracodorsal artery perforator flap and muscle-sparing latissimus dorsi flap.

INTRODUCTION: Around the knee reconstruction is challenging for reconstructive surgeons. Several methods have been proposed, including perforator and muscle flaps; however, all have advantages and disadvantages. As the success rate of free-flap surgery increases, reconstruction around the knee using this method is becoming increasingly popular. Nevertheless, there are no large-scale case reports in the previous literature using either a thoracodorsal artery perforator flap (latissimus dorsi (LD) perforator flap) or a muscle-sparing latissimus dorsi (msLD) flap for reconstruction around the knee. In this retrospective report, we describe our clinical experiences and present an algorithm regarding recipient vessel choice in free-flap reconstructive surgery of around the knee defects. PATIENT AND METHODS: Fifty-six cases in which a flap from the lateral thoracic area was used to reconstruct an around the knee defect between January 2016 and March 2022 were reviewed. The patients were aged 18-87 years (mean, 52.13 years), and of the 56 patients, 36 were male and 20 were female. Injuries were caused by trauma, contracture, rheumatoid vasculitis, tumor, infection, burns, sunken deformity, and pressure sores. The 56 cases included 22 with a defect including the knee, 14 with a defect below the knee (7 of the primary below-knee amputation [BKA] and 7 of the secondary BKA), 9 involving the distal medial thigh, 8 involving the distal lateral thigh, 2 involving the popliteal area, and 1 involving the middle thigh. Most cases were reconstructed using a single LD perforator flap or msLD flap. Chimeric or supplementary flaps were used when extensive coverage or dead space obliteration was required. The average size of the defect area was 253.6 cm2 (range: 5 × 6-21 × 39 cm2 ). RESULTS: In the cases, the recipient artery used included the following: descending genicular artery (23), superficial femoral artery (14), descending branch of the lateral circumflex femoral artery (14), anterior tibial artery (2), popliteal artery (2), and posterior tibial artery (1). The recipient vein included the greater saphenous vein (24), descending branch of the lateral circumflex femoral vein (14), superficial femoral vein (7), descending genicular vein (6), anterior tibial vein (2), popliteal vein (2), and posterior tibial vein (1). The average flap size was 281.8 cm2 (range: 4 × 8-35 × 19 cm2 ). All flaps survived; however, seven complications occurred, including 2 partial flap losses, 1 arterial insufficiency, 1 hematoma, 1 minor dehiscence, 1 donor-site graft loss, and 1 short BKA. Normal knee range of motion (121-140°) was observed in 34 patients and 16 showed varying degrees of limited range of motion. Motion was not observed in four patients who underwent knee fusion and could not be evaluated in two patients who underwent above-knee amputation. The mean follow-up duration was 24.6 months (range: 4-72 months). CONCLUSION: The LD perforator flap is ideal for the reconstruction of around the knee defects because it enables a long pedicle, large flap, and chimeric design. The msLD flap is ideal because it enables strong stump support, dead-space obliteration, and infection control. Moreover, since the two flaps are distant from the knee, this method is advantageous in terms of postoperative rehabilitation and there is minimal donor-site morbidity due to the thin nature of the LD muscle. In addition, the flap can be elevated in three positions and the operation can be completed without positional changes in various recipient vessel locations. Based on our experience, we conclude that the LD flap has the potential to be used as widely as or in preference to the anterolateral thigh flap in the reconstruction of around the knee defects.

Interaction of Thiol Antioxidants with α,ß-Unsaturated Ketone Moiety: Its Implication for Stability and Bioactivity of Curcuminoids.

Many biological functions of curcumin have been reported. As certain bioactivities of curcumin are eliminated by antioxidants, reactive oxygen species generated by curcumin have been suggested as a relevant mechanism. In the present study, the effects of different types of antioxidants on the stability and bioactivities of curcumin were analyzed. High concentrations (>4 mM) of thiol antioxidants, including N-acetylcysteine (NAC), glutathione (GSH), and ß-mercaptoethanol, accelerated the decomposition of curcumin and other curcuminoids; the submillimolar levels (<0.5 mM) of GSH and NAC rather improved their stability. Ascorbic acid or superoxide dismutase also stabilized curcumin, regardless of their concentration. The cellular levels and bioactivities of curcumin, including its cytotoxicity and the induction of heme oxygenase-1, were significantly reduced in the presence of 8 mM of GSH and NAC. The effects were enhanced in the presence of submillilmolar GSH and NAC, or non-thiol antioxidants. The present results indicate that antioxidants with a reduced thiol group could directly interact with the α,ß-unsaturated carbonyl moiety of curcuminoids and modulate their stability and bioactivity.

Monitoring trafficking and expression of hemagglutinin-tagged transient receptor potential melastatin 4 channel in mammalian cells.

The TRPM4 gene encodes a Ca2+-activated monovalent cation channel called transient receptor potential melastatin 4 (TRPM4) that is expressed in various tissues. Dysregulation or abnormal expression of TRPM4 has been linked to a range of diseases. We introduced the hemagglutinin (HA) tag into the extracellular S6 loop of TRPM4, resulting in an HA-tagged version called TRPM4-HA. This TRPM4-HA was developed to investigate the purification, localization, and function of TRPM4 in different physiological and pathological conditions. TRPM4-HA was successfully expressed in the intact cell membrane and exhibited similar electrophysiological properties, such as the current-voltage relationship, rapid desensitization, and current size, compared to the wild-type TRPM4. The presence of the TRPM4 inhibitor 9-phenanthrol did not affect these properties. Furthermore, a wound-healing assay showed that TRPM4-HA induced cell proliferation and migration, similar to the native TRPM4. Co-expression of protein tyrosine phosphatase, non-receptor type 6 (PTPN6 or SHP-1) with TRPM4-HA led to the translocation of TRPM4-HA to the cytosol. To investigate the interaction between PTPN6 and tyrosine residues of TRPM4 in enhancing channel activity, we generated four mutants in which tyrosine (Y) residues were substituted with phenylalanine (F) at the N-terminus of TRPM4. The YF mutants displayed properties and functions similar to TRPM4-HA, except for the Y256F mutant, which showed resistance to 9-phenanthrol, suggesting that Y256 may be involved in the binding site for 9-phenanthrol. Overall, the creation of HA-tagged TRPM4 provides researchers with a valuable tool to study the role of TRPM4 in different conditions and its potential interactions with other proteins, such as PTPN6.

Dual regulation of TRPV1 channels by phosphatidylinositol via functionally distinct binding sites.

Regulation of the heat- and capsaicin-activated transient receptor potential vanilloid 1 (TRPV1) channel by phosphoinositides is complex and controversial. In the most recent TRPV1 cryo-EM structure, endogenous phosphatidylinositol (PtdIns) was detected in the vanilloid binding site, and phosphoinositides were proposed to act as competitive vanilloid antagonists. This model is difficult to reconcile with phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] being a well-established positive regulator of TRPV1. Here we show that in the presence of PtdIns(4,5)P2 in excised patches, PtdIns, but not PtdIns(4)P, partially inhibited TRPV1 activity at low, but not at high capsaicin concentrations. This is consistent with PtdIns acting as a competitive vanilloid antagonist. However, in the absence of PtdIns(4,5)P2, PtdIns partially stimulated TRPV1 activity. We computationally identified residues, which are in contact with PtdIns, but not with capsaicin in the vanilloid binding site. The I703A mutant of TRPV1 showed increased sensitivity to capsaicin, as expected when removing the effect of an endogenous competitive antagonist. I703A was not inhibited by PtdIns in the presence of PtdIns(4,5)P2, but it was still activated by PtdIns in the absence of PtdIns(4,5)P2 indicating that inhibition, but not activation by PtdIns proceeds via the vanilloid binding site. In molecular dynamics simulations, PtdIns was more stable than PtdIns(4,5)P2 in this inhibitory site, whereas PtdIns(4,5)P2 was more stable than PtdIns in a previously identified, nonoverlapping, putative activating binding site. Our data indicate that phosphoinositides regulate channel activity via functionally distinct binding sites, which may explain some of the complexities of the effects of these lipids on TRPV1.

Insulin sensitizer MSDC-0602K in non-alcoholic steatohepatitis: A randomized, double-blind, placebo-controlled phase IIb study.

BACKGROUND & AIMS: MSDC-0602K is a novel insulin sensitizer designed to preferentially target the mitochondrial pyruvate carrier while minimizing direct binding to the transcriptional factor PPARγ. Herein, we aimed to assess the efficacy and safety of MSDC-0602K in patients with non-alcoholic steatohepatitis. METHODS: Patients with biopsy-confirmed NASH and fibrosis (F1-F3) were randomized to daily oral placebo, or 1 of 3 MSDC-0602K doses in a 52-week double-blind study. The primary efficacy endpoint was hepatic histological improvement of ≥2 points in non-alcoholic fatty liver disease activity score (NAS) with a ≥1-point reduction in either ballooning or lobular inflammation and no increase in fibrosis stage at 12 months. Secondary endpoints included NAS improvement without worsening fibrosis, NASH resolution, and fibrosis reduction. Exploratory endpoints included changes in insulin sensitivity, liver injury and liver fibrosis markers. RESULTS: Patients were randomly assigned to placebo (n = 94), or 62.5 mg (n = 99), 125 mg (n = 98), or 250 mg (n = 101) of MSDC-0602K. At baseline, glycated hemoglobin was 6.4 ±â€¯1.0%, 61.5% of patients had fibrosis F2/F3 and the average NAS was 5.3. The primary endpoint was reached in 29.7%, 29.8%, 32.9% and 39.5% of patients in the placebo, 62.5 mg, 125 mg and 250 mg dose arms, respectively, with adjusted odds ratios relative to placebo of 0.89 (95% CI 0.44-1.81), 1.22 (95% CI 0.60-2.48), and 1.64 (95% CI 0.83-3.27). The 2 highest doses of MSDC-0602K led to significant reductions in glucose, glycated hemoglobin, insulin, liver enzymes and NAS compared to placebo. The incidence of hypoglycemia and PPARγ-agonist-associated events such as edema and fractures were similar in the placebo and MSDC-0602K groups. CONCLUSIONS: MSDC-0602K did not demonstrate statistically significant effects on primary and secondary liver histology endpoints. However, effects on non-invasive measures of liver cell injury and glucose metabolism support further exploration of MSDC-0602K's safety and potential efficacy in patients with type 2 diabetes and liver injury. [ClinicalTrials.gov Identifier: NCT02784444]. LAY SUMMARY: First-generation insulin sensitizers are used to treat type 2 diabetes, but are associated with side effects including edema, bone fractures, and hypoglycemia. MSDC-0602K is a second-generation insulin sensitizer designed to reduce these side effects. We hypothesized that insulin sensitization could improve non-alcoholic steatohepatitis. In the current study of patients with non-alcoholic steatohepatitis, MSDC-0602K did not demonstrate significant effects on liver histology with the biopsy techniques used. However, useful information was gained for the design of future studies and MSDC-0602K significantly decreased fasting glucose, insulin, glycated hemoglobin, and markers of liver injury without dose-limiting side effects.

Two indoleamines are secreted from rat pineal gland at night and act on melatonin receptors but are not night hormones.

INTRODUCTION: At night, the pineal gland produces the indoleamines, melatonin, N-acetylserotonin (NAS), and N-acetyltryptamine (NAT). Melatonin is accepted as a hormone of night. Could NAS and NAT serve that role too? METHODS: Concentration-response measurements with overexpressed human melatonin receptors MT1 and MT2 ; mass spectrometry analysis of norepinephrine-stimulated secretions from isolated rat pineal glands; analysis of 24-hour periodic samples of rat blood. RESULTS: We show that NAT and NAS do activate melatonin receptors MT1 and MT2 , although with lower potency than melatonin, and that in vitro, melatonin and NAS are secreted from stimulated, isolated pineal glands in roughly equimolar amounts, but secretion of NAT was much less. All three were found at roughly equal concentrations in blood during the night. However, during the day, serum melatonin fell to very low values creating a high-amplitude circadian rhythm that was absent after pinealectomy, whereas NAS and NAT showed only small or no circadian variation. CONCLUSION: Blood levels of NAS and NAT were insufficient to activate peripheral melatonin receptors, and they were invariant, so they could not serve as circulating hormones of night. However, they could instead act in paracrine circadian fashion near the pineal gland or via other higher-affinity receptors.

Surviving and thriving: Voices of Latina/o engineering students at a Hispanic serving institution.

This study examined factors that played a role in Latina/o undergraduate students' persistence in engineering at a Hispanic serving institution (HSI; N = 10) using the consensual qualitative research method (CQR; Hill, Thompson, & Williams, 1997). Data analyses resulted in five domains: institutional conditions, additive intersectional burdens, personal and cultural wealth, coping skills, and engineering identity. Participants described how they persisted in the face of stressors, citing specific coping skills they developed over time as well as general personal and cultural strengths they carried with them into their pursuit of engineering. Although the structures of the students' institution were generally described as supportive, Latina participants reported experiences with gendered racism that created added barriers to their persistence in engineering. Supportive institutional conditions, personal and cultural assets, and adaptive coping strategies appeared to facilitate the development of a strong engineering identity, which helped to solidify students' sense of belonging, pride, and commitment to complete their degree. Results highlight the need to address intersecting experiences of privilege and oppression to promote access and equity for Latinas/os in engineering. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Social cognitive predictors of engineering students' academic persistence intentions, satisfaction, and engagement.

The demand for high quality engineers is of particular importance as engineering jobs are projected to grow in the next 10 years (United States Bureau of Labor Statistics, 2018). More work is needed to understand factors related to academic engagement, satisfaction, and persistence intentions of Latino/as and women in engineering: 2 underrepresented groups in the engineering pipeline. We present findings that explored the role of social-cognitive, environmental, and personality variables in engineering persistence intentions, engagement and satisfaction of a diverse sample of 1,335 engineering students using an extension of the integrative social cognitive career theory model (SCCT; Lent et al., 2013). Results indicated that (a) the hypothesized model fit the data well for the full sample and across 8 subsamples based on gender-ethnicity (i.e., Latinas, Latinos, White women, and White men) and ethnicity-school type (i.e., Latina/os at Hispanic-serving institutions [HSIs], Latina/os at predominantly White institutions [PWIs], Whites at HSIs, and Whites at PWIs), (b) all but 5 model parameters were significant and positive for the full sample, (c) a subset of model parameters differed by the interactions of race/ethnicity-gender and race/ethnicity-school type groups, and (d) the relations within the model explained a significant amount of variance in engineering academic engagement, satisfaction, and persistence intentions for the full sample and 8 subsamples. Implications of the findings for educational and career interventions aimed at retaining Latina/os and women in engineering are discussed in relation to building on social cognitions in engineering academic engagement, satisfaction, and persistence intentions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Nicotinic acid activates the capsaicin receptor TRPV1: Potential mechanism for cutaneous flushing.

OBJECTIVE: Nicotinic acid (also known as niacin or vitamin B3), widely used to treat dyslipidemias, represents an effective and safe means to reduce the risk of mortality from cardiovascular disease. Nonetheless, a substantial fraction of patients discontinue treatment because of a strong side effect of cutaneous vasodilation, commonly termed flushing. In the present study, we tested the hypothesis that nicotinic acid causes flushing partially by activating the capsaicin receptor TRPV1, a polymodal cellular sensor that mediates the flushing response on consumption of spicy food. APPROACH AND RESULTS: We observed that the nicotinic acid-induced increase in blood flow was substantially reduced in Trpv1(-/-) knockout mice, indicating involvement of the channel in flushing response. Using exogenously expressed TRPV1, we confirmed that nicotinic acid at submillimolar to millimolar concentrations directly and potently activates TRPV1 from the intracellular side. Binding of nicotinic acid to TRPV1 lowers its activation threshold for heat, causing channel opening at physiological temperatures. The activation of TRPV1 by voltage or ligands (capsaicin and 2-aminoethoxydiphenyl borate) is also potentiated by nicotinic acid. We further demonstrated that nicotinic acid does not compete directly with capsaicin but may activate TRPV1 through the 2-aminoethoxydiphenyl borate activation pathway. Using live-cell fluorescence imaging, we observed that nicotinic acid can quickly enter the cell through a transporter-mediated pathway to activate TRPV1. CONCLUSIONS: Direct activation of TRPV1 by nicotinic acid may lead to cutaneous vasodilation that contributes to flushing, suggesting a potential novel pathway to inhibit flushing and to improve compliance.

Identification and assessment of markers of biotin status in healthy adults.

Human biotin requirements are unknown and the identification of reliable markers of biotin status is necessary to fill this knowledge gap. Here, we used an outpatient feeding protocol to create states of biotin deficiency, sufficiency and supplementation in sixteen healthy men and women. A total of twenty possible markers of biotin status were assessed, including the abundance of biotinylated carboxylases in lymphocytes, the expression of genes from biotin metabolism and the urinary excretion of biotin and organic acids. Only the abundance of biotinylated 3-methylcrotonyl-CoA carboxylase (holo-MCC) and propionyl-CoA carboxylase (holo-PCC) allowed for distinguishing biotin-deficient and biotin-sufficient individuals. The urinary excretion of biotin reliably identified biotin-supplemented subjects, but did not distinguish between biotin-depleted and biotin-sufficient individuals. The urinary excretion of 3-hydroxyisovaleric acid detected some biotin-deficient subjects, but produced a meaningful number of false-negative results and did not distinguish between biotin-sufficient and biotin-supplemented individuals. None of the other organic acids that were tested were useful markers of biotin status. Likewise, the abundance of mRNA coding for biotin transporters, holocarboxylase synthetase and biotin-dependent carboxylases in lymphocytes were not different among the treatment groups. Generally, datasets were characterised by variations that exceeded those seen in studies in cell cultures. We conclude that holo-MCC and holo-PCC are the most reliable, single markers of biotin status tested in the present study.

Structural basis of the activation of TRPV5 channels by long-chain acyl-Coenzyme-A.

Long-chain acyl-coenzyme A (LC-CoA) is a crucial metabolic intermediate that plays important cellular regulatory roles, including activation and inhibition of ion channels. The structural basis of ion channel regulation by LC-CoA is not known. Transient receptor potential vanilloid 5 and 6 (TRPV5 and TRPV6) are epithelial calcium-selective ion channels. Here, we demonstrate that LC-CoA activates TRPV5 and TRPV6 in inside-out patches, and both exogenously supplied and endogenously produced LC-CoA can substitute for the natural ligand phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in maintaining channel activity in intact cells. Utilizing cryo-electron microscopy, we determined the structure of LC-CoA-bound TRPV5, revealing an open configuration with LC-CoA occupying the same binding site as PI(4,5)P2 in previous studies. This is consistent with our finding that PI(4,5)P2 could not further activate the channels in the presence of LC-CoA. Our data provide molecular insights into ion channel regulation by a metabolic signaling molecule.

A Case Report of Madelung's Disease.

Madelung's disease (MD) is a rare disease characterized by diffuse, nonencapsulated, multiple fat masses in different areas of the body. In this case report, we present a case of MD in Asia and its management. A 66-year-old man with a history of hypertension presented with massive growth of soft tissue around the neck, breasts, upper back, and lower abdomen. Preoperative magnetic resonance imaging revealed remarkably hypertrophic fat tissue around the neck and anterior chest was wall, which consistent with the diagnosis of MD. Multiple linear incisions were made on the neck and 763, 186, 635 g of posterior, right, and left fat tissues were excised, respectively. A single wide, transverse incision was done to excise 1,072 g of fat from the upper back. Masses of both breasts were excised, preserving the inferior pedicle, weighing 1,086 (right) and 1,164 g (left). The recovery was optimal and the patient was discharged without complications. In this case, we excised the adipose masses as much as possible and improved contour and symmetry. However, the fat infiltrations in the patient were diffusely distributed, making total fat excision difficult. This rare case report may help in managing patients with MD.

Roles of anti- and pro-oxidant potential of cinnamic acid and phenylpropanoid derivatives in modulating growth of cultured cells.

Cinnamic acid (CiA) and phenylpropanoid derivatives are widely distributed in plant foods. In this study, anti- and pro-oxidant properties of the derivatives and their roles in modulating cell growth were investigated. Ferulic acid, sinapinic acid, caffeic acid (CaA), and 3,4-dihydroxyhydrocinnamic acid (DHC) showed strong radical scavenging activities. They, except DHC, also performed considerable inhibitory effects on lipid peroxidation and reduced levels of intracellular reactive oxygen species (ROS). CaA and DHC, however, produced substantial amount of H2O2 with oxidative degradation in culture conditions. CaA and DHC (> 400 µM) showed potent cytotoxic effects which were abolished by superoxide dismutase/catalase; they significantly enhanced cell growth ROS-dependently at low levels (~ 100 µM). CiA derivatives without bearing hydroxyl group did not show any appreciable antioxidant activities. The results indicate that CiA derivatives with ortho-dihydroxyl group had strong anti- and pro-oxidant properties, which also play an important role in modulating cell growth. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01042-x.

An Unorthodox Mechanism Underlying Voltage Sensitivity of TRPV1 Ion Channel.

While the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) channel is a polymodal nociceptor for heat, capsaicin, and protons, the channel's responses to each of these stimuli are profoundly regulated by membrane potential, damping or even prohibiting its response at negative voltages and amplifying its response at positive voltages. Therefore, voltage sensitivity of TRPV1 is anticipated to play an important role in shaping pain responses. How voltage regulates TRPV1 activation remains unknown. Here, it is shown that voltage sensitivity does not originate from the S4 segment like classic voltage-gated ion channels; instead, outer pore acidic residues directly partake in voltage-sensitive activation, with their negative charges collectively constituting the observed gating charges. Outer pore gating-charge movement is titratable by extracellular pH and is allosterically coupled to channel activation, likely by influencing the upper gate in the ion selectivity filter. Elucidating this unorthodox voltage-gating process provides a mechanistic foundation for understanding TRPV1 polymodal gating and opens the door to novel approaches regulating channel activity for pain management.

Gain-of-Function Mutations in TRPM4 Activation Gate Cause Progressive Symmetric Erythrokeratodermia.

Transient receptor potential (TRP) channels respond to various chemical and physical stimuli by mediating cation influx. The skin expresses abundant TRP channels of different subtypes, which play an essential role in the maintenance of skin functionality. Here, we report cases of mutations in TRPM4, which encodes TRPM4, a Ca2+-activated monovalent cation channel, as a cause of an autosomal dominant form of progressive symmetric erythrokeratodermia. In three separate families with progressive symmetric erythrokeratodermia, we identified two missense mutations (c.3099C>G and c.3119T>C) that produce p.Ile1033Met and p.Ile1040Thr, both of which are located in the S6 transmembrane domain of the TRPM4 protein. The substitutions are expected to directly affect activation gating of TRPM4 according to the cryo-EM structures. Electrophysiological studies of the mutants showed substantial hyperactivity, as evidenced by pronounced baseline activity, enhanced sensitivity to intracellular Ca2+, and an elevated resting membrane potential. In vitro studies showed enhanced proliferation in keratinocytes overexpressing either of the mutants. We also detected an up-regulation of markers for proliferation and differentiation of keratinocytes in the affected skin tissues. Our study identified TRPM4 as an important player in the pathogenesis of skin TRP channelopathies and a potential target for treatment of skin hyperkeratotic disorders.

Treatment for gastric 'indefinite for neoplasm/dysplasia' lesions based on predictive factors.

BACKGROUND: Gastric 'indefinite for neoplasm/dysplasia' (IFND) is a borderline lesion that is difficult to diagnose as either regenerative or neoplastic. There is a need for guidance in the identification of a subset of patients, who have an IFND lesion with a higher risk of malignant potential, to enable risk stratification and optimal management. AIM: To determine the clinical and pathologic factors for the accurate diagnosis of gastric IFND lesions. METHODS: In total, 461 gastric lesions diagnosed via biopsy as IFND lesions were retrospectively evaluated. Endoscopic resection (n = 134), surgery (n = 22), and follow-up endoscopic biopsy (n = 305) were performed to confirm the diagnosis. The time interval from initial biopsy to cancer diagnosis was measured, and diagnostic delays were categorized as > 2 wk, > 2 mo, > 6 mo, and > 1 year. The IFND lesions presenting as regenerating atypia (60%) or atypical epithelia (40%) at initial biopsy were adenocarcinomas in 22.6%, adenomas in 8.9%, and gastritis in 68.5% of the cases. RESULTS: Four clinical factors [age ≥ 60 years (2.445, 95%CI: 1.305-4.580, P = 0.005), endoscopic size ≥ 10 mm (3.519, 95%CI: 1.891-6.548, P < 0.001), single lesion (5.702, 95%CI: 2.212-14.696, P < 0.001), and spontaneous bleeding (4.056, 95%CI: 1.792-9.180, P = 0.001)], and two pathologic factors [atypical epithelium (25.575, 95%CI: 11.537-56.695, P < 0.001], and repeated IFND diagnosis [6.022, 95%CI: 1.822-19.909, P = 0.003)] were independent risk factors for gastric cancer. With two or more clinical factors, the sensitivity and specificity for carcinoma were 91.3% and 54.9%, respectively. Ten undifferentiated carcinomas were initially diagnosed as IFND. In the subgroup analysis, fold change (5.594, 95%CI: 1.458-21.462, P = 0.012) predicted undifferentiated or invasive carcinoma in the submucosal layers or deeper. Diagnostic delays shorter than 1 year were not associated with worse prognoses. Extremely well-differentiated adenocarcinomas accounted for half of the repeated IFND cases and resulted in low diagnostic accuracy even on retrospective blinded review. CONCLUSION: More than two clinical and pathologic factors each had significant cut-off values for gastric carcinoma diagnosis; in such cases, endoscopic resection should be considered.

Hemispheric asymmetry of speed-dependent intercerebellar connectivity.

The coordinated and timed movements of human limbs require interactive cerebellar functions. We investigated the function of intercerebellar connectivity in controlling the movement speed of both hands with functional MRI experiments. Nine healthy, right-handed subjects performed finger movements at lower and higher speeds, as instructed. With finger movements at a higher speed, regional responses in the bilateral cerebellum were increased in both hands. However, the contribution of the ipsilateral cerebellum to the contralateral cerebellum, which was assessed by psychophysiological interaction analysis, was increased only in the dominant hand. Results of this study indicated that there is a speed-dependent modulation of intercerebellar connectivity for finger movement and this modulation has hemispheric asymmetry.