Molecular and circuit determinants in the globus pallidus mediating control of cocaine-induced behavioral plasticity.

The globus pallidus externus (GPe) is a central component of the basal ganglia circuit, receiving strong input from the indirect pathway and regulating a variety of functions, including locomotor output and habit formation. We recently showed that it also acts as a gatekeeper of cocaine-induced behavioral plasticity, as inhibition of parvalbumin-positive cells in the GPe (GPe PV ) prevents the development of cocaine-induced reward and sensitization. However, the molecular and circuit mechanisms underlying this function are unknown. Here we show that GPe PV cells control cocaine reward and sensitization by inhibiting GABAergic neurons in the substantia nigra pars reticulata (SNr GABA ), and ultimately, selectively modulating the activity of ventral tegmental area dopamine (VTA DA ) cells projecting to the lateral shell of the nucleus accumbens (NAcLat). A major input to GPe PV cells is the indirect pathway of the dorsomedial striatum (DMS D 2 ), which receives DAergic innervation from collaterals of VTA DA →NAcLat cells, making this a closed-loop circuit. Cocaine likely facilitates reward and sensitization not directly through actions in the GPe, but rather in the upstream DMS, where the cocaine-induced elevation of DA triggers a depression in DMS D 2 cell activity. This cocaine-induced elevation in DA levels can be blocked by inhibition of GPe PV cells, closing the loop. Interestingly, the level of GPe PV cell activity prior to cocaine administration is correlated with the extent of reward and sensitization that animals experience in response to future administration of cocaine, indicating that GPe PV cell activity is a key predictor of future behavioral responses to cocaine. Single nucleus RNA-sequencing of GPe cells indicated that genes encoding voltage-gated potassium channels KCNQ3 and KCNQ5 that control intrinsic cellular excitability are downregulated in GPe PV cells following a single cocaine exposure, contributing to the elevation in GPe PV cell excitability. Acutely activating channels containing KCNQ3 and/or KCNQ5 using the small molecule carnosic acid, a key psychoactive component of Salvia rosmarinus (rosemary) extract, reduced GPe PV cell excitability and also impaired cocaine reward, sensitization, and volitional cocaine intake, indicating its potential as a therapeutic to counteract psychostimulant use disorder. Our findings illuminate the molecular and circuit mechanisms by which the GPe orchestrates brain-wide changes in response to cocaine that are required for reward, sensitization, and self-administration behaviors.

Ophthalmate is a new regulator of motor functions via CaSR: Implications for movement disorders.

Dopamine's role as the principal neurotransmitter in motor functions has long been accepted. We broaden this conventional perspective by demonstrating the involvement of non-dopaminergic mechanisms. In mouse models of Parkinson's Disease (PD), we observed that L-DOPA elicited a substantial motor response even when its conversion to dopamine was blocked by inhibiting the enzyme aromatic amino acid decarboxylase (AADC). Remarkably, the motor activity response to L-DOPA in the presence of an AADC inhibitor (NSD1015) showed a delayed onset, yet greater intensity and longer duration, peaking at 7 hours, compared to when L-DOPA was administered alone. This suggests an alternative pathway or mechanism, independent of dopamine signaling, mediating the motor functions. We sought to determine the metabolites associated with the pronounced hyperactivity observed, using comprehensive metabolomics analysis. Our results revealed that the peak in motor activity induced by NSD1015/L-DOPA in PD mice is associated with a surge (20-fold) in brain levels of the tripeptide ophthalmic acid (OA, also known as ophthalmate in its anionic form). Interestingly, we found that administering ophthalmate directly to the brain rescued motor deficits in PD mice in a dose-dependent manner. We investigated the molecular mechanisms underlying ophthalmate's action and discovered, through radioligand binding and cAMP-luminescence assays, that ophthalmate binds to and activates the calcium-sensing receptor (CaSR). Additionally, our findings demonstrated that a CaSR antagonist inhibits the motor-enhancing effects of ophthalmate, further solidifying the evidence that ophthalmate modulates motor functions through the activation of the CaSR. The discovery of ophthalmate as a novel regulator of motor function presents significant potential to transform our understanding of brain mechanisms of movement control and the therapeutic management of related disorders.

Canagliflozin Pretreatment Attenuates Myocardial Dysfunction and Improves Postcardiac Arrest Outcomes After Cardiac Arrest and Cardiopulmonary Resuscitation in Mice.

OBJECTIVE: The SGLT2 inhibitor, canagliflozin, not only reduces glycemia in patients with type 2 diabetes but also exerts cardioprotective effects in individuals without diabetes. However, its potential beneficial effects in cardiac arrest have not been characterized. The purpose of this study was to examine the protective effect of canagliflozin pretreatment on postresuscitation-induced cardiac dysfunction in vivo. METHODS: Male C57/BL6 mice were randomized to vehicle (sham and control) or canagliflozin treatment groups. All mice except for the sham-operated mice were subjected to potassium chloride-induced cardiac arrest followed by chest compressions and intravenous epinephrine for resuscitation. Canagliflozin therapy efficacies were evaluated by electrocardiogram, echocardiography, histological analysis, inflammatory response, serum markers of myocardial injury, protein phosphorylation analysis, and immunohistological assessment. RESULTS: Canagliflozin-pretreated mice exhibited a higher survival rate (P < 0.05), a shorter return of spontaneous circulation (ROSC) time (P < 0.01) and a higher neurological score (P < 0.01 or P < 0.001) than control mice after resuscitation. Canagliflozin was effective at improving cardiac arrest and resuscitation-associated cardiac dysfunction, indicated by increased left ventricular ejection fraction and fractional shortening (P < 0.001). Canagliflozin reduced serum levels of LDH, CK-MB and α-HBDH, ameliorated systemic inflammatory response, and diminished the incidence of early resuscitation-induced arrhythmia. Notably, canagliflozin promoted phosphorylation of cardiac STAT-3 postresuscitation. Furthermore, pharmacological inhibition of STAT-3 by Ag490 blunted STAT-3 phosphorylation and abolished the cardioprotective actions of canagliflozin. CONCLUSIONS: Canagliflozin offered a strong cardioprotective effect against cardiac arrest and resuscitation-induced cardiac dysfunction. This canagliflozin-induced cardioprotection is mediated by the STAT-3-dependent cell-survival signaling pathway.

Crucial role for Sodium Hydrogen Exchangers in SGLT2 inhibitor-induced arterial relaxations.

Introduction: Sodium dependent glucose transporter 2 (SGLT2 or SLC5A2) inhibitors effectively lower blood glucose and are also approved treatments for heart failure independent of raised glucose. One component of the cardioprotective effect is reduced cardiac afterload but the mechanisms underlying peripheral relaxation are ill defined and variable. We speculated that SGLT2 inhibitors promoted arterial relaxation via the release of the potent vasodilator calcitonin gene-related peptide (CGRP) from sensory nerves independent of glucose transport. Experimental approach: The functional effects of SGLT2 inhibitors (dapagliflozin, empagliflozin, ertugliflozin) and the sodium/hydrogen exchanger 1 (NHE1) blocker cariporide were determined on pre-contracted mesenteric and renal arteries from male Wistar rats using Wire-Myography. SGLT2, NHE1, CGRP and TRPV1 expression in both arteries was determined by Western blot and immunohistochemistry. Kv7.4/5/KCNE4 and TRPV1 currents were measured in the presence and absence of dapagliflozin and empagliflozin. Results: All SGLT2 inhibitors produced a concentration dependent relaxation (1µM-100µM) of mesenteric arteries that was considerably greater than in renal arteries. Cariporide relaxed mesenteric arteries but not renal arteries. Immunohistochemistry with TRPV1 and CGRP antibodies revealed a dense innervation of sensory nerves in mesenteric arteries that was absent in renal arteries. Consistent with a greater sensory nerve component, the TRPV1 agonist capsaicin produced significantly greater relaxations in mesenteric arteries compared to renal arteries. Relaxations to dapagliflozin, empagliflozin and cariporide were attenuated by incubation with the CGRP receptor antagonist BIBN-4096, the Kv7 blocker linopirdine and the TRPV1 antagonist AMG-517 as well as by depletion of neuronal CGRP. Neither dapagliflozin nor empagliflozin directly activated heterologously expressed TRPV1 channels or Kv7 channels. Strikingly, only NHE1 colocalised with TRPV1 in sensory nerves, and cariporide pre-application prevented the relaxant response to SGLT2 inhibitors. Conclusions: SGLT2 inhibitors relax mesenteric arteries by a novel mechanism involving the release of CGRP from sensory nerves following inhibition of the Na + /H + exchanger.

Medicinal plant rosemary relaxes blood vessels by activating vascular smooth muscle KCNQ channels.

The evergreen plant rosemary (Salvia rosmarinus) has been employed medicinally for centuries as a memory aid, analgesic, spasmolytic, vasorelaxant and antihypertensive, with recent preclinical and clinical evidence rationalizing some applications. Voltage-gated potassium (Kv) channels in the KCNQ (Kv7) subfamily are highly influential in the nervous system, muscle and epithelia. KCNQ4 and KCNQ5 regulate vascular smooth muscle excitability and contractility and are implicated as antihypertensive drug targets. Here, we found that rosemary extract potentiates homomeric and heteromeric KCNQ4 and KCNQ5 activity, resulting in membrane hyperpolarization. Two rosemary diterpenes, carnosol and carnosic acid, underlie the effects and, like rosemary, are efficacious KCNQ-dependent vasorelaxants, quantified by myography in rat mesenteric arteries. Sex- and estrous cycle stage-dependence of the vasorelaxation matches sex- and estrous cycle stage-dependent KCNQ expression. The results uncover a molecular mechanism underlying rosemary vasorelaxant effects and identify new chemical spaces for KCNQ-dependent vasorelaxants.

Ancient medicinal plant rosemary contains a highly efficacious and isoform-selective KCNQ potassium channel opener.

Voltage-gated potassium (Kv) channels in the KCNQ subfamily serve essential roles in the nervous system, heart, muscle and epithelia. Different heteromeric KCNQ complexes likely serve distinct functions in the brain but heteromer subtype-specific small molecules for research or therapy are lacking. Rosemary (Salvia rosmarinus) is an evergreen plant used medicinally for millennia for neurological and other disorders. Here, we report that rosemary extract is a highly efficacious opener of heteromeric KCNQ3/5 channels, with weak effects on KCNQ2/3. Using functional screening we find that carnosic acid, a phenolic diterpene from rosemary, is a potent, highly efficacious, PIP2 depletion-resistant KCNQ3 opener with lesser effects on KCNQ5 and none on KCNQ1 or KCNQ2. Carnosic acid is also highly selective for KCNQ3/5 over KCNQ2/3 heteromers. Medicinal chemistry, in silico docking, and mutagenesis reveal that carboxylate-guanidinium ionic bonding with an S4-5 linker arginine underlies the KCNQ3 opening proficiency of carnosic acid, the effects of which on KCNQ3/5 suggest unique therapeutic potential and a molecular basis for ancient neurotherapeutic use of rosemary.

Behavioral and neuro-functional consequences of eliminating the KCNQ3 GABA binding site in mice.

Voltage-gated potassium (Kv) channels formed by α subunits KCNQ2-5 are important in regulating neuronal excitability. We previously found that GABA directly binds to and activates channels containing KCNQ3, challenging the traditional understanding of inhibitory neurotransmission. To investigate the functional significance and behavioral role of this direct interaction, mice with a mutated KCNQ3 GABA binding site (Kcnq3-W266L) were generated and subjected to behavioral studies. Kcnq3-W266L mice exhibited distinctive behavioral phenotypes, of which reduced nociceptive and stress responses were profound and sex-specific. In female Kcnq3-W266L mice, the phenotype was shifted towards more nociceptive effects, while in male Kcnq3-W266L mice, it was shifted towards the stress response. In addition, female Kcnq3-W266L mice exhibited lower motor activity and reduced working spatial memory. The neuronal activity in the lateral habenula and visual cortex was altered in the female Kcnq3-W266L mice, suggesting that GABAergic activation of KCNQ3 in these regions may play a role in the regulation of the responses. Given the known overlap between the nociceptive and stress brain circuits, our data provide new insights into a sex-dependent role of KCNQ3 in regulating neural circuits involved in nociception and stress, via its GABA binding site. These findings identify new targets for effective treatments for neurological and psychiatric conditions such as pain and anxiety.

Native American ataxia medicines rescue ataxia-linked mutant potassium channel activity via binding to the voltage sensing domain.

There are currently no drugs known to rescue the function of Kv1.1 voltage-gated potassium channels carrying loss-of-function sequence variants underlying the inherited movement disorder, Episodic Ataxia 1 (EA1). The Kwakwaka'wakw First Nations of the Pacific Northwest Coast used Fucus gardneri (bladderwrack kelp), Physocarpus capitatus (Pacific ninebark) and Urtica dioica (common nettle) to treat locomotor ataxia. Here, we show that extracts of these plants enhance wild-type Kv1.1 current, especially at subthreshold potentials. Screening of their constituents revealed that gallic acid and tannic acid similarly augment wild-type Kv1.1 current, with submicromolar potency. Crucially, the extracts and their constituents also enhance activity of Kv1.1 channels containing EA1-linked sequence variants. Molecular dynamics simulations reveal that gallic acid augments Kv1.1 activity via a small-molecule binding site in the extracellular S1-S2 linker. Thus, traditional Native American ataxia treatments utilize a molecular mechanistic foundation that can inform small-molecule approaches to therapeutically correcting EA1 and potentially other Kv1.1-linked channelopathies.

The plant-derived alkaloid aloperine prevents ischemia/reperfusion injury-induced sudden cardiac death.

Sudden cardiac death (SCD) remains a major cause of global mortality. In addition to modern interventions, botanical folk medicines have long been used to treat cardiovascular disease, although the efficacy and underlying mechanisms are often unresolved. Aloperine, a bioactive quinolizidine alkaloid isolated from Sophora alopecuroides plants, exhibits antioxidant, anti-inflammatory, antitumor, and vasorelaxant properties, but possible antiarrhythmic effects of aloperine in SCD are unclear. Here, we examined whether aloperine protects against ischemia and reperfusion injury-associated lethal ventricular arrhythmia and sudden cardiac death. Rats were divided into sham, control, and aloperine groups, and reperfusion-provoked ventricular arrhythmogenesis, cardiac damage markers, and signaling pathways quantified following left main coronary artery ischemia and reperfusion. In vitro studies of effects of aloperine on hERG and Kv4.3 cardiac voltage-gated potassium (Kv) channels were performed using two-electrode voltage clamp analysis of cloned channels expressed in Xenopus laevis oocytes. Aloperine pretreatment (10 mg/kg) did not affect baseline cardiac electrical stability; yet, it reduced ventricular arrhythmogenesis and susceptibility to SCD (mortality rate: control: 64.3%; aloperine: 0%) induced by reperfusion injury. Aloperine also reduced serum levels of LDH, CK-MB, α-HBDH, and cTnI post-I/R, and stimulated phosphorylation of ventricular ERK1/2 and STAT-3, which are key components of RISK and SAFE signaling pathways. Inhibition of either ERK1/2 (with U0126) or STAT-3 (with Ag490) abolished aloperine-induced anti-arrhythmic effects and ERK1/2 and STAT-3 phosphorylation. Interestingly, while aloperine (100 µM) had no effect on cloned Kv4.3 activity, aloperine (1 µM and up) negative-shifted the voltage dependence of hERG activation by ~10 mV and increased peak hERG current by 35%. Thus, aloperine exerts striking anti-arrhythmic effects against myocardial ischemia and reperfusion injury-induced severe lethal ventricular arrhythmia and sudden cardiac death via the ERK1/2/STAT-3 signaling pathway, with potential additional contribution from increased cardiac myocyte repolarization capacity via augmented hERG activity.

Remote limb ischemic postconditioning attenuates myocardial dysfunction induced by testicular torsion/detorsion in rats.

Torsion of the spermatic cord is a urological emergency that must be treated immediately with surgery, yet detorsion of the testis can cause testicular tissue damage because of ischemia-reperfusion (I/R) injury. I/R injury is a complex pathophysiological process that may affect the functions of distant organs. Here, we examined whether testicular torsion/detorsion (TT) causes myocardial dysfunction. We next investigated the potential beneficial effect and underlying mechanisms of remote ischemic postconditioning (RIPost) on cardiac function after testicular torsion/detorsion. Male Sprague-Dawley rats were assigned to three different sets of experimental groups. Testicular I/R was induced by rotating the right testis to 1080° clockwise for 3 h followed by 3 h of detorsion. RIPost was induced at the onset of testicular detorsion by four cycles of 5-min bilateral femoral artery occlusion with 5-min reperfusion. Cardiac function was determined postdetorsion, and the cardioprotective effect of RIPost was examined. Testicular torsion/detorsion-treated rats had reduced serum testosterone levels, impaired systemic hemodynamics, elevated systemic inflammatory responses, and increased serum levels of lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB), α-hydroxybutyrate dehydrogenase (α-HBDH), and cardiac troponin I (cTnI). However, RIPost attenuated remote heart dysfunction induced by testicular torsion/detorsion. Furthermore, RIPost enhanced the phosphorylation of ventricular signal transducer and activator of transcription (STAT)-3, which is a key component of the survivor activating factor enhancement (SAFE) signaling pathways. Inhibition of STAT-3 with Ag490 abolished the RIPost-induced cardioprotection and STAT-3 phosphorylation. Testicular torsion followed by detorsion may cause impaired cardiac function in rats. RIPost effectively attenuates this remote cardiac dysfunction. RIPost-induced protective effects may be mediated by the STAT-3 signaling pathway.

Empagliflozin protects against renal ischemia/reperfusion injury in mice.

Renal ischemia/reperfusion (I/R) can induce acute kidney injury. Empagliflozin is a newly developed inhibitor of sodium-glucose cotransporter-2 (SGLT2) approved as an antidiabetic medication for patients with type 2 diabetes mellitus. Despite the established cardioprotective functions of empagliflozin, its protective role in renal I/R is unclear. Here, the present study evaluated the renoprotective effects of empagliflozin in a mouse model of renal I/R injury. Male C57/BL6 mice were allocated to sham-operated, I/R, and empagliflozin groups. Kidney pedicles on both sides were clamped for 45 min and were reperfused for 24 h. Empagliflozin (1 mg/kg) was administered to the mice for 2 days preischemia. The GSK-3ß inhibitor SB216763 was administered intravenously at the beginning of reperfusion (0.1 mg/kg). Renal function and histological scores were evaluated. The kidneys were taken for immunohistochemical analysis, western blotting and apoptosis measurements. We found that empagliflozin decreased serum levels of creatinine and urea, reduced the average kidney weight-to-tibia length ratio, attenuated tubular damage, reduced renal proinflammatory cytokine expression and inhibited apoptosis in injured kidneys. Furthermore, empagliflozin increased renal glycogen synthase kinase 3ß (GSK-3ß) phosphorylation post I/R. Pharmacological inhibition of GSK-3ß activity mimicked the renal protective effects offered by empagliflozin. In summary, these results support a protective role of empagliflozin against renal I/R injury.

KCNQ5 activation by tannins mediates vasorelaxant effects of barks used in Native American botanical medicine.

Tree and shrub barks have been used as folk medicine by numerous cultures across the globe for millennia, for a variety of indications, including as vasorelaxants and antispasmodics. Here, using electrophysiology and myography, we discovered that the KCNQ5 voltage-gated potassium channel mediates vascular smooth muscle relaxant effects of barks used in Native American folk medicine. Bark extracts (1%) from Birch, Cramp Bark, Slippery Elm, White Oak, Red Willow, White Willow, and Wild Cherry each strongly activated KCNQ5 expressed in Xenopus oocytes. Testing of a subset including both the most and the least efficacious extracts revealed that Red Willow, White Willow, and White Oak KCNQ-dependently relaxed rat mesenteric arteries; in contrast, Black Haw bark neither activated KCNQ5 nor induced vasorelaxation. Two compounds common to the active barks (gallic acid and tannic acid) had similarly potent and efficacious effects on both KCNQ5 activation and vascular relaxation, and this together with KCNQ5 modulation by other tannins provides a molecular basis for smooth muscle relaxation effects of Native American folk medicine bark extracts.

Case report: A novel loss-of-function pathogenic variant in the KCNA1 cytoplasmic N-terminus causing carbamazepine-responsive type 1 episodic ataxia.

Episodic ataxia is an umbrella term for a group of nervous system disorders that adversely and episodically affect movement. Episodes are recurrent, characterized by loss of balance and coordination and can be accompanied by other symptoms ranging from nausea to hemiplegia. Episodic Ataxia Type 1 (EA1) is an inherited, autosomal dominant disease caused by sequence variants in KCNA1, which encodes the voltage-gated potassium channel, KCNA1 (Kv1.1). Here we report a novel loss-of-function KCNA1 pathogenic variant [c.464T>C/p.Leu155Phe] causing frequent, sudden onset of clumsiness or staggering gait in the young female proband. The gene variant was maternally inherited and the mother, whose symptoms also began in childhood, has a normal MRI and EEG, slurred speech and dystonic movements involving upper extremities and mouth. Both mother and daughter are responsive to carbamazepine. Cellular electrophysiology studies of KCNA1-L155P potassium channels revealed complete but non-dominant loss of function, with reduced current and altered gating in heterozygous channels. To our knowledge this is the first EA1-associated pathogenic variant located in the KCNA1 cytoplasmic N-terminus, expanding the reported clinically sensitive domains of the channel.

Kv Channel Ancillary Subunits: Where Do We Go from Here?

Voltage-gated potassium (Kv) channels each comprise four pore-forming α-subunits that orchestrate essential duties such as voltage sensing and K+ selectivity and conductance. In vivo, however, Kv channels also incorporate regulatory subunits-some Kv channel specific, others more general modifiers of protein folding, trafficking, and function. Understanding all the above is essential for a complete picture of the role of Kv channels in physiology and disease.

Alzheimer's disease is associated with disruption in thiamin transport physiology: A potential role for neuroinflammation.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by Amyloid-ß peptide (Aß) containing plaques and cognitive deficits. The pathophysiology of AD also involves neuroinflammation. Vitamin B1 (thiamin) is indispensable for normal cellular energy metabolism. Thiamin homeostasis is altered in AD, and its deficiency is known to aggravate AD pathology. Little, however, is known about possible alterations in level of expression of thiamin transporters-1 and -2 (THTR-1 and -2) in the brain of AD, and whether pro-inflammatory cytokines affect thiamin uptake by brain cells. We addressed these issues using brain tissue samples [prefrontal cortex (PFC) and hippocampus (HIP)] from AD patients and from 5XFAD mouse model of AD, together with cultured human neuroblastoma SH-SY5Y cells as model. Our results revealed a significantly lower expression of both THTR-1 and THTR-2 in the PFC and HIP of AD patients and 5XFAD mouse model of AD compared to appropriate normal controls. Further, we found that exposure of the SH-SY5Y cells to pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) led to a significant inhibition in thiamin uptake. Focusing on IL-1ß, we found the inhibition in thiamin uptake to be time-dependent and reversible; it was also associated with a substantial reduction in expression of THTR-1 (but not THTR-2) protein and mRNA as well as a decrease in promoter activity of the SLC19A2 gene (which encodes THTR-1). Finally, using transcriptomic analysis, we found that thiamin availability in SH-SY5Y cells caused changes in the expression of genes relevant to AD pathways. These studies demonstrate, for the first time, that thiamin transport physiology/molecular biology parameters are negatively impacted in AD brain and that pro-inflammatory cytokines inhibit thiamin uptake by neuroblastoma cells. The results also support a possible role for thiamin in the pathophysiology of AD.

Protective effect of remote liver ischemic postconditioning on pulmonary ischemia and reperfusion injury in diabetic and non-diabetic rats.

Pulmonary ischemia and reperfusion (I/R) injury occurs in many clinical conditions and causes severe damage to the lungs. Diabetes mellitus (DM) predisposes to pulmonary I/R injury. We previously found that remote liver ischemia preconditioning protected lungs against pulmonary I/R injury. The aim of the present study was to investigate whether remote liver ischemic postconditioning (RLIPost) attenuates pulmonary damage induced by I/R injury in non-diabetic or diabetic rats. Male Sprague-Dawley rats were assigned into non-diabetic and diabetic groups. All rats except for the sham were exposed to 45 min of left hilum occlusion followed by 2 h of reperfusion. RLIPost was conducted at the onset of pulmonary reperfusion by four cycles of 5 min of liver ischemia and reperfusion. Lung injury was assessed by the wet/dry weight ratio, pulmonary oxygenation, histopathological changes, apoptosis and the expression of inflammatory cytokines. Reperfusion-associated protein phosphorylation states were determined. RLIPost offered strong pulmonary-protection in both non-diabetic and diabetic rats, as reflected in reduced water content and pulmonary structural damage, recovery of lung function, inhibition of apoptosis and inflammation after ischemia-reperfusion. RLIPost induced the activation of pulmonary STAT-3, a key component in the SAFE pathway, but not activation of the proteins in the RISK pathway, in non-diabetic rats. In contrast, RLIPost-induced pulmonary protection in diabetic lungs was independent of SAFE or RISK pathway activation. These results demonstrate that RLIPost exerts pulmonary protection against I/R-induced lung injury in non-diabetic and diabetic rats. The underlying mechanism for protection may be different in non-diabetic (STAT-3 dependent) versus diabetic (STAT-3 independent) rats.

KCNQ Potassium Channels as Targets of Botanical Folk Medicines.

Since prehistory, human species have depended on plants for both food and medicine. Even in countries with ready access to modern medicines, alternative treatments are still highly regarded and commonly used. Unlike modern pharmaceuticals, many botanical medicines are in widespread use despite a lack of safety and efficacy data derived from controlled clinical trials and often unclear mechanisms of action. Contributing to this are the complex and undefined composition and likely multifactorial mechanisms of action and multiple targets of many botanical medicines. Here, we review the newfound importance of the ubiquitous KCNQ subfamily of voltage-gated potassium channels as targets for botanical medicines, including basil, capers, cilantro, lavender, fennel, chamomile, ginger, and Camellia, Sophora, and Mallotus species. We discuss the implications for the traditional use of these plants for disorders such as seizures, hypertension, and diabetes and the molecular mechanisms of plant secondary metabolite effects on KCNQ channels.

Empagliflozin Protects against Pulmonary Ischemia/Reperfusion Injury via an Extracellular Signal-Regulated Kinases 1 and 2-Dependent Mechanism.

Ischemia/reperfusion (I/R) injury of the lung can lead to extensive pulmonary damage. Sodium-glucose cotransporter-2 (SGLT2) inhibitors are insulin-independent, oral antihyperglycemic agents used for treating type 2 diabetes mellitus (T2DM). Although their cardioprotective properties have been reported, their potential roles in pulmonary protection in vivo are poorly characterized. Here, we tested a hypothesis that empagliflozin, an SGLT2 inhibitor, can protect lungs in a mouse model of lung I/R injury induced by pulmonary hilum ligation in vivo. We assigned C57/BL6 mice to sham-operated, nonempagliflozin-treated control, or empagliflozin-treated groups. Pulmonary I/R injury was induced by 1-hour left hilum ligation followed by 2-hour reperfusion. Using quantitative polymerase chain reaction (q-PCR) and Western blot analysis, we demonstrate that SGLT2 is highly expressed in mouse kidney but is weakly expressed in mouse lung (n = 5-6 per group, P < 0.01 or P < 0.001). Empagliflozin improved respiratory function, attenuated I/R-induced lung edema, lessened structural damage, inhibited apoptosis, and reduced inflammatory cytokine production and protein concentration in bronchoalveolar lavage (BAL) fluid [P < 0.05 or P < 0.001 versus control group (CON)]. In addition, empagliflozin enhanced phosphorylation of pulmonary extracellular signal-regulated kinases 1 and 2 (ERK1/2) post-I/R injury in vivo (P < 0.001, versus CON, n = 5 per group). We further showed that pharmacological inhibition of ERK1/2 activity reversed these beneficial effects of empagliflozin. In conclusion, we showed that empagliflozin exerts strong lung protective effects against pulmonary I/R injury in vivo, at least in part via the ERK1/2-mediated signaling pathway. SIGNIFICANCE STATEMENT: Pulmonary ischemia-reperfusion (I/R) can exacerbate lung injury. Empagliflozin is a new antidiabetic agent for type 2 diabetes mellitus. This study shows that empagliflozin attenuates lung damage after pulmonary I/R injury in vivo. This protective phenomenon was mediated at least in part via the extracellular signal-regulated kinases 1 and 2-mediated signaling pathway. This opens a new avenue of research for sodium-glucose cotransporter-2 inhibitors in the treatment of reperfusion-induced acute pulmonary injury.