Social withdrawal during cocaine abstinence is a significant predictor of relapse, yet the neuroendocrine mechanisms underlying this vulnerability remain poorly understood, particularly in females. Estradiol, a potent neuromodulator of mesocorticolimbic circuitry, regulates dopamine-dependent processes that encode social motivation. L-type calcium channels (LTCCs) similarly regulate neuronal excitability and plasticity in corticolimbic regions implicated in addiction and affective regulation, and estradiol interacts with LTCC signaling through both membrane-initiated and transcriptional mechanisms. However, whether estradiol and LTCCs functionally converge to regulate social behavior during cocaine abstinence is unknown. Here, we used a preclinical behavioral pharmacology approach to examine this interaction in female Sprague-Dawley rats. Ovariectomized (OVX) rats with or without 17β-estradiol replacement underwent jugular catheterization and self-administered cocaine (0.5 mg/kg/inf, FR1) or saline for 10 days, followed by 17 days of forced abstinence. Social preference was assessed using a three-chamber social interaction test, with systemic isradipine (1.2 mg/kg, i.p.) administered 15 min prior to testing. Cocaine abstinence significantly reduced social preference in intact females. LTCC blockade with isradipine restored social preference, but this effect was dependent on ovarian hormone status: isradipine normalized social behavior in sham-operated and OVX + E2 rats but not in OVX rats lacking estradiol. Multiple linear regression confirmed that ovarian hormone status and isradipine treatment, but not total cocaine intake, significantly predicted social preference, with a robust hormone × isradipine interaction explaining 44.6% of behavioral variance. These findings demonstrate that estradiol does not simply protect against abstinence-related social deficits but rather biases neural signaling such that social behavior becomes sensitive to LTCC-dependent mechanisms. This work identifies a functional estradiol-LTCC interaction regulating social motivation during cocaine abstinence and highlights the importance of hormonal state in shaping sex-specific addiction vulnerability.

Background/Objectives: Interindividual pharmacokinetic (PK) variability remains a daunting challenge for effective and safe drug therapy. Despite the widespread use of direct oral anticoagulants (DOACs) and calcium channel blockers (CCBs), a substantial number of adverse drug reactions have been reported for both classes. Herein, this study aimed to assess and analyze the PK variability of DOACs and CCBs across diverse clinical and demographic profiles under both single- and multiple-dose conditions. Methods: A PubMed search identified clinical PK studies reporting maximum plasma concentration (Cmax) and/or area under the concentration-time curve (AUC). The coefficient of variation (CV%) was calculated and used as a measure of PK variability. A CV% < 40% indicated low-to-moderate variability, and a CV% > 40% was defined as high variability. Results: A total of 264 studies were included following systematic screening, and the dataset was further characterized according to population features and clinical context. Among DOACs, edoxaban exhibited the lowest PK variability, whereas dabigatran showed the highest. CCBs demonstrated a broad variability spectrum, ranging from predictable agents (amlodipine and felodipine) to highly variable compounds (nisoldipine, isradipine, nimodipine, diltiazem, and verapamil). Studies evaluating drug-drug interactions, ethnicity, and specific drug-related factors were associated with increased PK variability. Conclusions: These findings suggest that fixed-dose strategies may not be universally appropriate for DOACs and CCBs, particularly in high-risk subgroups where altered exposure may lead to sub- or supratherapeutic concentrations and compromise clinical outcomes. Therefore, clinicians should avoid evaluating individual risk factors in isolation and instead consider the patient's complete profile when selecting and adjusting pharmacotherapy.

Cardiovascular disease remains a leading cause of mortality worldwide, and macrophage-derived foam-cell formation represents an important event in atherosclerosis. VAV2, a Rho-family guanine nucleotide-exchange factor, participates in signalling pathways associated with oxidized low-density lipoprotein uptake and macrophage lipid accumulation. In this study, a structure-based drug-repurposing workflow was used to identify clinically relevant compounds with predicted affinity for a full-length VAV2 structural model. Virtual screening, molecular docking, ADMET prediction, three independent 200-ns molecular-dynamics simulations, principal-component analysis, and MM-PBSA calculations prioritized talazoparib, tivozanib, and isradipine for further evaluation. In THP-1-derived macrophages, talazoparib reduced oxLDL-induced intracellular neutral-lipid accumulation at a sub-cytotoxic concentration. In a complementary DiI-oxLDL assay, all three compounds reduced cell-associated DiI-oxLDL fluorescence relative to vehicle control. These findings provide preliminary computational and cellular support for further investigation of the selected compounds. However, direct binding to or inhibition of VAV2 has not been demonstrated and requires biochemical, genetic, pharmacological, and in vivo validation.

Fatty Acid Transport Protein 2 (FATP2) couples fatty acid uptake to intracellular activation and is associated with pathological lipid accumulation in cancer and nonalcoholic fatty liver disease. Here, we present cryo-electron microscopy structures of human FATP2 across its reaction cycle. Our structures suggest that FATP2 recruits fatty acids directly from the membrane interface through a hydrophobic tunnel. Catalysis involves a ∼130° rotation of the C-terminal domain, a transition trapped by the antihypertensive drugs isradipine and benidipine. Both drugs lock the enzyme in a thioester-forming state, but benidipine exhibits superior efficacy by extending a bulky moiety into the primary catalytic tunnel to sterically block substrate entry. Furthermore, we identify a product inhibition mechanism where excess acyl-CoA traps the enzyme, potentially limiting metabolic overload. These findings provide a structural framework for understanding vectorial fatty acid channeling and a scaffold for developing modulators of metabolic flux.

Immune checkpoint blockade targeting the PD-1/PD-L1 axis using monoclonal antibodies has revolutionized cancer therapy by inducing durable antitumor responses across multiple cancer types. However, antibody-based therapeutics suffer from several limitations, including poor tissue permeability, immune-related adverse effects, complex manufacturing processes, and high production costs. These challenges underscore the need for small-molecule inhibitors (SMIs) as alternative therapeutic agents; nevertheless, to date, no FDA-approved small molecule has demonstrated proven in vivo efficacy against the PD-1/PD-L1 axis. Given the prolonged timelines and substantial costs associated with de novo drug discovery, drug repurposing represents an efficient and cost-effective strategy. In this study, we employed an integrated computational approach to identify potential SMIs capable of disrupting the PD-1/PD-L1 interaction. Structure-based virtual screening of 20 dihydropyridine (DHP) calcium channel blockers (CCBs) was performed using AutoDock Vina, along with CA-170 as a reference inhibitor. Several lead compounds were identified and evaluated based on binding affinity, bonding pose, and interaction patterns. Among the screened compounds, Pranidipine, Isradipine, and Efonidipine exhibited the most favorable binding profiles toward PD-1/PD-L1 complex inhibition. Furthermore, molecular dynamics (MD) simulations confirmed the stability of the interactions between these lead compounds and PD-L1, especially Pranidipine, over time. Collectively, our in silico findings suggest that selected DHP-CCBs may represent promising repurposing candidates for targeting the PD-1/PD-L1 immune checkpoint. However, further in vitro studies are required to validate their potential biological activity.

Rett syndrome (RTT) is a rare X-linked progressive neurodevelopmental disorder affecting predominantly females with no cure and a prevalence of ~1 in 10,000 female birth worldwide. Before mutations in the methyl-CpG binding protein 2 (MECP2) gene were identified to cause classic RTT, there were suggestions that RTT is a mitochondrial disease. Being an essential organelle for all eukaryotic cells, the mitochondria produce energy, buffer calcium, and regulate the generation of reactive oxygen species. Indeed, accumulated reports documented mitochondrial abnormalities in RTT patient biopsies, and animal models and human stem cell models of RTT, including reduced ATP production, altered mitochondrial structure, increased systemic oxidative stress, abnormal calcium activity, mtDNA copy number, and deficiencies in mitochondrial enzyme activity. While it remains unclear how loss of MECP2 function leads to wide-ranging mitochondrial deficits, improving mitochondrial function could still bring benefits to RTT patients. After defining the mitochondrial membrane potential deficit in astrocytes differentiated from RTT patient-specific induced pluripotent stem cells (iPSC), we established a novel high-throughput screening (HTS) platform based on the JC-10 mitochondrial membrane potential (MMP) assay, which served as a rapid primary readout. All primary hits were subsequently validated by independent functional assays to confirm their effects on mitochondrial health. Using this system, we performed a small-molecule screening of 1,134 selected US Food and Drug Administration (FDA)-approved drugs and a small interfering RNA (siRNA) screening of 336 genes upregulated in RTT astrocytes and identified candidate drugs and candidate genes that reversed the MMP deficits in RTT astrocytes. Among the candidate drug hits, isradipine, a dihydropyridine calcium-channel blocker, provided preliminary evidence of neuroprotective effects both in vitro and in vivo. Among the candidate gene hits, LRRC17, a gene encoding a secreted protein, emerged as a strong candidate mediator whose elevated levels are strongly associated with and likely contribute to various observed cellular deficits. siRNA knockdown of LRRC17 not only rescued mitochondrial dysfunction in RTT astrocytes but also reversed deficits in neurons cultured in astrocyte-conditioned media. Our study provides new insights into mitochondrial dysfunction in RTT and establishes an HTS platform for the initial identification of novel therapeutic targets for follow-up studies.

Poor survival of transplanted midbrain dopaminergic neurons (mDANs) remains a key barrier for stem cell-based Parkinson's disease (PD) therapy. Cav1.3-containing L-type calcium channel blockers have been shown to prevent native mDAN loss in PD animal models and patients. Here, we aim to investigate whether they also enhance the post-transplant survival of stem cell-derived mDANs. We found that Cav1.3 is highly expressed in human embryonic stem cell-derived mDANs. Cav1.3 inhibitors including isradipine and cp-PYT significantly reduced apoptosis and improved mDAN survival in both interferon gamma (IFN-γ)- and tumor necrosis factor alpha (TNF-α)-induced inflammatory models, as well as in the 6-OHDA-induced toxic model in vitro. Mechanistically, their protective effects are mediated through suppressing the CaMKII-p65-p53 signaling pathway. Moreover, we showed that cp-PYT treatment enhanced mDAN survival while reducing mature graft volume post-transplantation. Therefore, Cav1.3 inhibition may represent a clinically relevant strategy to enhance the survival of human pluripotent stem cell (hPSC)-derived mDANs in cell therapy for PD.

Cardiovascular conditions disrupt the normal functioning of the heart and blood vessels, often due to underlying conditions like atherosclerosis or hypertension. Antihypertensive medications are essential in cardiovascular disease management, encompassing several major drug classes with distinct mechanisms of action. Hence, this review evaluated the impact of various antihypertensive treatments on cardiovascular event reduction in asymptomatic carotid artery stenosis (CAS) patients. A comprehensive literature search was conducted from inception to 2024 on various databases by using specific keywords, and based on the eligibility criteria, three observational cohort studies and six randomized controlled trials (RCTs) of the 540 records retrieved were incorporated in this systematic review. The Newcastle-Ottawa scale was used to assess the methodological quality of the cohort studies, and the risk of bias visualization tool was used for RCTs. Data were then systematically extracted and analyzed. The results reported that enalapril and fosinopril demonstrated dual benefits in blood pressure (BP) reduction and vascular remodeling, though meta-analysis showed statistically insignificant improvements in regional cerebral blood flow (CI: -0.84, 6.08, P = 0.14, I[2]= 94%). Similarly, isradipine, lacidipine, and amlodipine improved carotid hemodynamics and cerebral perfusion, with meta-analysis favoring calcium channel blocker intervention for blood pressure management (CI: -3.25 to 7.64, P = 0.43). On the other hand, thiazide diuretics effectively reduced BP but showed limited efficacy in preventing atherosclerosis progression. In addition, angiotensin II receptor blockers (ARBs) significantly reduced 5-year stroke rates from 11% to 3.5%. Moreover, beta-blockers showed specific benefits, with metoprolol improving plaque echogenicity (57.3 ± 16.8 vs. 51.8 ± 20.0, p = 0.006) and reducing cardiovascular events (17% vs. 37% placebo, p = 0.011), while labetalol effectively managed post-endarterectomy hypertension. In conclusion, antihypertensive treatments showed varying effectiveness in cardiovascular event reduction and improvements in vessel measures.

Neurodegenerative movement disorders, encompassing conditions such as Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, represent a significant burden on individuals, families, and healthcare systems globally. Traditional drug discovery approaches for these disorders have encountered challenges, including high costs and lengthy timelines. Drug repurposing has emerged in recent years as a promising approach to expedite the discovery of new treatments by leveraging existing drugs approved for other indications. This review explores the landscape of drug repurposed for neurodegenerative movement disorders, highlighting promising candidates, underlying mechanisms, and clinical implications. The rationale behind repurposing, including the advantages of utilizing existing pharmacological agents with established safety profiles and known pharmacokinetics, along with techniques utilized for repurposing (computational and experimental), have been elaborated. Several studies on the potential of pre-existing drugs such as isradipine, tetracycline, ambroxol, metformin, deferiprone, simvastatin, etc., which have been repurposed for neurodegenerative movement disorders, including Parkinson's disease, Huntington's disease, Alzheimer's disease, Multiple Sclerosis, etc. have been discussed. Further, the current scenario and future prospective of drug repurposing have also been touched upon.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder after Alzheimer's disease, primarily affecting the aging population. Despite the introduction of levodopa in the 1960s and significant progress in managing PD symptoms, no treatment has yet demonstrated neuroprotective efficacy. The complexity and multifactorial nature of PD continue to present substantial therapeutic challenges, prompting researchers to explore alternative approaches such as drug repurposing. This strategy offers a time- and cost-efficient route to drug development. Recent efforts have focused on repurposing agents originally developed for metabolic and other non-neurological disorders. Ongoing research is actively investigating several repurposed drugs originally intended for different conditions, including anti-hypertensives (isradipine, dexmedetomidine), anti-asthmatics (montelukast), phosphodiesterase5 inhibitors (sildenafil), antimicrobials (rifaximin), and various CNS-active agents (aripiprazole, escitalopram, paroxetine, venlafaxine, duloxetine, caffeine). While drug repurposing holds considerable promise, comprehensive preclinical and clinical studies are essential to validate these candidates for PD-specific therapeutic applications. This review aims to provide an in-depth overview of PD, encompassing its pathological and molecular characteristics, and to critically evaluate the current landscape of drug repurposing strategies to develop effective therapies for PD.

Equilibrative nucleoside transporters (ENTs) facilitate the equilibrative movement of nucleosides and nucleobases across cell membranes in a sodium-independent manner. ENT1 (SLC29A1) and ENT2 (SLC29A2) also transport nucleoside analogs and can affect the pharmacokinetics and pharmacodynamics of drugs used in cancer, viral infections, and inflammatory disorders. ENT1 and ENT2 may be differentiated functionally by their sensitivity to inhibition by nitrobenzylthioinosine (NBMPR), and we used this difference in NBMPR sensitivity to create a HeLa-based ENT2 inhibition assay. We then screened a library of 1600 diverse compounds composed of drugs and natural products for inhibition against ENT1 and ENT2, selecting a subset of compounds for side-by-side comparison of dose-response studies. We used these screening data to build machine learning models for ENT1 and ENT2 inhibition, employing dataset balancing and conformal prediction to adjust for the asymmetrical nature of the data. A random forest model predicted a prospective test set of 44 additional molecules (from the MedChem Express Drug Repurposing Library [2700 compounds]) as potential ENT1 inhibitors with 59% accuracy. This resulted in the identification of the Food and Drug Administration-approved drugs isradipine, avanafil, and istradefylline as inhibitors of ENT1. These new experimental and computational methods and models for these clinically relevant transporters can be used to evaluate drug-transporter interactions early in drug discovery, before testing in vivo. SIGNIFICANCE STATEMENT: Recent regulatory guidance have suggest the inclusion of the equilibrative nucleoside transporters (eg, ENT1 and ENT2) as transporters with emerging clinical relevance for in vitro and in vivo assessment. We have screened over 1600 diverse molecules, allowing us to build machine learning models that in turn were further used to make predictions to validate the models. Our combined experimental and machine learning approach resulted in the identification of multiple Food and Drug Administration-approved medications as inhibitors of ENT1 or ENT2.

Calcium channel blockers (CCBs), originally developed for cardiovascular indications, have gained attention for their therapeutic potential in neuropsychiatric, endocrine, and pain-related disorders. In neuropsychiatry, nimodipine and isradipine, both L-type CCBs, show mood-stabilizing and neuroprotective effects, with possible benefits in depression, bipolar disorder, and schizophrenia. In endocrinology, verapamil, a non-dihydropyridine L-type blocker, has been associated with the preservation of pancreatic β-cell function and reduced insulin dependence in diabetes. CCBs may also aid in managing primary aldosteronism and pheochromocytoma, particularly in patients with calcium signaling mutations. In pain medicine, α2δ ligands and selective blockers of N-type and T-type channels demonstrate efficacy in neuropathic and inflammatory pain. However, their broader use is limited by challenges in central nervous system (CNS) penetration, off-target effects, and heterogeneous trial outcomes. Future research should focus on pharmacogenetic stratification, novel delivery platforms, and combination strategies to optimize repurposing of CCBs across disciplines.

Periods of cocaine abstinence are associated with a high risk of relapse, often triggered by exposure to drug-associated cues. Previous research has implicated L-type calcium channels (LTCCs) in drug-seeking behaviors, yet their role in cue-induced relapse, particularly in females, remains underexplored. This study investigated the effects of LTCC inhibition on cue-induced cocaine-seeking behavior during abstinence in female Sprague-Dawley rats. Following a 10-day cocaine self-administration and a 14-day forced abstinence period, the rats were tested for cue-induced cocaine-seeking after receiving systemic administration of isradipine, a non-selective LTCC inhibitor (0.0 mg/kg, 0.1 mg/kg, 0.4 mg/kg, or 1.2 mg/kg, i.p.). Isradipine significantly reduced cue-induced cocaine-seeking in a dose-dependent manner without affecting cocaine-taking or natural reward-taking or seeking behaviors. Notably, these findings in females were comparable to our prior results observed in males, demonstrating that LTCC inhibition selectively attenuates the impact of cocaine-associated cues across sexes. These results highlight the translational potential of LTCCs as a therapeutic agent to reduce relapse risk in cocaine-dependent individuals. This study underscores the importance of considering sex-specific mechanisms in addiction treatment and calls for further research into LTCCs as a target for relapse prevention.

Cocaine abstinence and withdrawal are linked to relapse and heightened anxiety. While L-type calcium channels (LTCCs) have been associated with cocaine use disorders in humans and drug-seeking in rodents, their role in mood-related symptoms during cocaine abstinence remains unclear. We addressed this by investigating the ability of LTCC blockade with isradipine to alter the mood-related behavioral phenotypes induced by cocaine abstinence. Female and male Sprague-Dawley rats were trained to self-administer cocaine or saline, followed by a 14-day period of abstinence. Subsequently, behavioral responses were examined using the sucrose preference test (SPT), elevated plus maze (EPM), and forced swim test (FST). Cocaine-abstinent rats showed decreased open arm time in the EPM and increased immobility time in the FST with no changes in the SPT. Isradipine (0.4 mg/kg or 1.2 mg/kg, i.p.), reversed the anxiogenic-like EPM behavior in female cocaine-abstinent rats, whereas only the higher dose (1.2 mg/kg, i.p.) was effective in male cocaine-abstinent rats. In the FST, the lower dose (0.4 mg/kg, i.p.) of isradipine reversed the increased immobility time observed in cocaine-abstinent female and male rats, with no isradipine effect in saline-abstinent rats. In contrast 1.2 mg/kg, i.p. isradipine decreased immobility time in both cocaine and saline abstinent female and male rats. In summary, isradipine administration reversed the anxiogenic and increased the FST immobility time associated with cocaine abstinence in a dose and sex-dependent manner. The data underscore the importance of further investigation of LTCC mechanisms and their therapeutic potential for mood disorders associated with cocaine use disorder.