Molecular Pharmacology

Background. Polypharmacy is an important source of phenoconversion caused by drug interactions potentially modulated by genetic variability. Aims. To develop a linear phenoconversion model for TDM data and provide quantitative estimates of drug-drug-gene interactions (DDGIs) in the pharmacogenetic phenotype groups of CYP2C19. Methods. Escitalopram TDM data in a large real-world sample (n=2,852) was analysed for phenoconversion of CYP2C19 activity. Co-medication was identified by reprocessing high-resolution mass-spectra (Orbitrap). We developed a statistical model to identify inhibition from co-medication in the CYP2C19 and in alternative elimination pathways. We extended the model to estimate the inhibition ensuing from individual co-medications, using a single model for all data to account for multiple co-medications and confounders simultaneously. A Bayesian approach allowed us to stabilize the fit and provide well-calibrated credibility intervals. Results. Reprocessing of TDM analyses identified 17 co-medications, which were shown to phenoconvert CYP2C19 activity proportionally to the activity in non-medicated phenotypes. Phenoconversion decreased the original CYP2C19 activity by about one third for a co-medication that corresponded to a 100% substrate of CYP2C19. The extent of CYP2C19 phenoconversion correlated strongly with the fractional contribution of CYP2C19 to the metabolism of the specific co-medication reported in the pharmacogenetic literature (R2=0.55) so long as the mechanism was competitive inhibition. Conclusion. We provide the statistical methodology to estimate phenoconversion from co-medication in TDM data and combine TDM and pharmacogenetic datasets in future studies aiming at establishing quantitative models of DDGIs.

IntroductionThe RAS(ON) multi-selective daraxonrasib (RMC-6236) inhibitor is effective in patients with NSCLC KRAS mutant cancers. Tolerance to daraxonrasib invariably develops by mechanisms that remain unclear. There is no known involvement of the M1C oncogenic protein in daraxonrasib resistance. MethodsNSCLC H358 KRAS(G12C), H2122 KRAS(G12C) and patient derived MGH1112 KRAS(G12C) cells with acquired daraxonrasib resistance were investigated for M1C dependence in studies of SHP2, STAT1/3 and NF-KB activation, clonogenicity, and self-renewal capacity. ResultsWe demonstrate that M1C is induced as a protective response in NSCLC KRAS(G12C) mutant cells treated with daraxonrasib. We report that M1C forms novel cell membrane-associated biomolecular condensates with the SHP2 protein tyrosine phosphatase in driving daraxonrasib resistance. M1C integrates SHP2 activation with induction of (i) oncostatin-m/gp130/STAT3 signaling, and (ii) the NF-{kappa}B-mediated epithelial-mesenchymal transition (EMT) pathway. The functional significance of this M1C-driven pathway is supported by the demonstration that targeting STAT3 and NF-{kappa}B reverses daraxonrasib resistance. Consistent with M1C dependence, we also show that targeting M1C is effective against daraxonrasib-resistant NSCLC KRAS mutant cell line and tumor models. In contrast, M1C drives sotorasib resistance by STAT1-mediated inflammatory signaling, demonstrating that M1C confers resistance to KRAS(G12C)-selective and RAS(ON) tri-complex inhibitors by noncongruent mechanisms. ConclusionsThese findings demonstrate that M1C is required for daraxonrasib tolerance and is a potential target for the treatment of patients with NSCLC KRAS(G12C) mutant tumors refractory to this agent.

It is well established that activating the mGluR2 metabotropic glutamate receptor (mGluR2), which is the main presynaptic autoreceptor for glutamate in the brain, attenuates the behavioral and electrophysiological actions of LSD and other psychedelics. However, the mechanisms responsible for these actions are controversial. The two competing mechanistic hypotheses have been proposed to explain this phenomenon are: (1) direct actions mediated by mGluR2/5-HT2A heterodimers, and (2) inhibition of 5-HT2A-mediated excitation of pyramidal neurons via presynaptic inhibition of glutamate release by mGluR2 receptors. Consistent with prior reports, we show mGluR2 agonist pretreatment attenuates the head twitch response induced by the psychedelic drug 1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in these mice. We next employed multiple orthogonal in vivo and in vitro approaches to explore the potential for direct physical interactions between mGluR2 and 5-HT2A receptors. We next engineered mice to express mGluR2-mCherry-CT and 5-HT2A-eGFP-CT tagged receptors and found no evidence for receptor colocalization or oligomerization under basal or 5-HT2A agonist-exposed conditions in vitro or in vivo. Radioligand binding and kinetic analyses revealed no evidence for mGluR2-mediated modulation of 5-HT2A ligand binding in vitro or in vivo. Collectively, our findings support models in which mGluR2 signaling modulates the activity of Gq-coupled 5-HT2A receptors in layer V pyramidal neurons, rather than models positing the requirement of mGluR2/5-HT2A multimers.

Chemokines orchestrate immune cell trafficking through receptor-mediated signaling and are implicated in inflammatory, autoimmune, and neuropathic disorders. The XCL1-XCR1 axis is of particular interest because XCR1 is selectively expressed on mature conventional type 1 dendritic cells (cDC1s), where it supports communication with activated CD8+ T cells and NK cells and promotes antigen cross-presentation. This selectivity has made XCR1 an attractive target for dendritic cell-based cancer vaccines, while emerging evidence also links XCL1-XCR1 signaling to neuroinflammation and pain. Despite its therapeutic potential, the mechanisms governing XCR1 activation and trafficking remain understudied. Here, we characterize XCR1 expression, membrane trafficking, and basal internalization to define mechanisms that may influence therapeutic targeting. We show that XCR1 undergoes constitutive internalization through a {beta}-arrestin-independent but adaptor protein 2 (AP2)-dependent pathway, distinguishing it from other chemokine receptors with constitutive endocytosis. Furthermore, we identify specific sequence motifs critical for its subcellular localization and intracellular trafficking. These findings provide new mechanistic insights into XCR1 regulation and may inform the development of targeted therapeutics and antigen-delivery strategies in cancer and inflammation.

The platelet P2Y1 receptor (P2Y1R) is necessary for inflammation, signalling via Rho-GTPase pathways to elicit functions that are distinct from aggregation (PLC-dependent canonical signalling pathway). Whether these distinct platelet inflammatory functions can be selectively suppressed to preserve hemostasis through the rational design of P2Y1R antagonists has not been explored. In silico molecular docking analysis examined biased nucleotide interactions within the P2Y1R binding pocket. The identified possible key amino acid residues guided rational design to synthesize compounds for pathway selective inhibition, evolving from nucleotide to non-nucleotide structures. The nucleotide analogue KMR-82-13 was predicted to engage distinct regions of the binding pocket and selectively inhibited platelet chemotaxis while preserving aggregation. These findings informed the design of a non-nucleotide compound KSN-159-27, aiming to retain key KMR-82-13-like interactions while improving drug-like properties. Docking and molecular dynamics simulation supported a stable but dynamic binding mode for KSN-159-27 within the P2Y1R pocket, consistent with pathway-selective inhibition. KSN-159-27 displayed characteristics of a pathway selective inverse agonist at P2Y1R towards G12/13-mediated pathways, but not those associated by Gq activation in P2Y1R-transfected HEK293T cells. KSN-159-27 showed functionally selective inhibition for platelet P2Y1R-mediated functions. In vivo, KSN-159-27 suppressed inflammatory cell recruitment, whilst preserving bleeding time and ADP-induced thromboembolic responses, in contrast to the neutral P2Y1R antagonist MRS2500. This first demonstration for the rational design of a pathway selective inverse agonist at platelet P2Y1Rs has significant implications for novel therapeutic strategies developed to safely target platelet activation during inflammation, in contrast to current anti-platelet drugs used in the prevention of thrombosis. Key PointsO_LIBiased inverse platelet P2Y1R agonists selectively supress inflammation whilst preserving hemostasis and the ability of platelets to aggregate. C_LIO_LIBiased inverse agonism selectively inhibited P2Y1R G12/13 (Rho-GTPAse functions) but not Gq activities (PLC functions). C_LI

Dysregulated gut homing of leukocytes drives chronic inflammation in Crohns disease (CD). We employed phage display selection campaigns with libraries of stabilized, constrained peptides against endogenous conformation states of the cannabinoid receptor CB2R on human T cells, to discover novel receptor antagonists with potential to inhibit gut homing. Cluster and frequency analysis of 50,000 enriched sequences resulted in expression and functional characterisation of 10 protein candidates using assays of glucose uptake, ERK phosphorylation (pERK) and beta-arrestin recruitment. Each candidate antagonised CB2R activity with recorded IC50 values of between 5-10 nM. Cannabinoid receptor nanodisc binding experiments and SPR confirmed CB2R selectivity. SLKC_09 with an IC50 of 5.4 nM, was studied in a mouse model of chronic ileitis where it significantly inhibited gut homing of CD4+ & CD8+ naive, effector and memory cell types. Our findings highlight an alternative route to therapeutic inhibition of leukocyte trafficking in CD with a biologic inhibitor of CB2R.

Background: Sphingosine 1-phosphate receptor (S1PR) modulators can cause transient, dose-related negative chronotropic effects. Mocravimod is an oral S1PR modulator that is developed as a maintenance therapy in allogenic haematopoietic cell transplantation (allo-HCT). This phase I study evaluated whether two dose-titration regimens attenuate early bradycardia when initiating mocravimod while preserving pharmacokinetic (PK) and pharmacodynamic (PD) activity. Patients and methods: In this randomized, double-blind, placebo-controlled, parallel-group study, healthy adults received once-daily oral mocravimod using either dose titration (DT) regimen DT1 (0.3-2.0 mg with 4-day stepwise escalation) or regimen DT2 (0.5 mg to Day 14, 1.2 mg Days 15-18, then 2 mg), a fixed 2 mg regimen, or placebo for 21 days. The primary endpoint was the number of bradycardia episodes on treatment initiation and dose-escalation days derived from 24-hour Holter monitoring; PK of mocravimod and mocravimod-phosphate (whole blood) and PD effects (absolute lymphocyte count [ALC]) were assessed. Results: Fifty-six participants were randomized and 53 completed the study. Both titration regimens resulted in fewer bradycardia episodes than fixed initiation at 2 mg during the first week of treatment. Differences between titration and fixed dosing were no longer evident after Day 9, consistent with tolerance development. PK profiles were consistent with prior phase I data. By Day 21, DT1 achieved exposures close to the fixed 2 mg regimen, whereas DT2 yielded lower exposures, reflecting slower escalation. Peripheral lymphopenia developed in all active treatment groups and was comparable between regimens by Day 21, returning toward baseline by study end. Safety was similar between titration regimens and placebo, with similar distribution and incidence of adverse events. No serious adverse events occurred. Conclusion: Two practical titration regimens mitigated the early negative chronotropic effect observed with fixed-dose initiation of mocravimod at 2 mg once daily. Importantly, titration preserved the expected PK and PD profile, supporting dose escalation as an effective initiation strategy to improve early cardiac tolerability.

Background & Aims: Activation of apoptosis signal-regulating kinase 1 (ASK1), a ubiquitous redox-sensitive kinase, results in inflammation, apoptosis, and fibrosis, key common pathways in human liver disease. SRT-015 is a novel, small molecule inhibitor of ASK1. This study evaluated the in vitro efficacy of SRT-015, compared it to other ASK1 inhibitors, and determined the in vivo efficacy of SRT-015 across multiple acute and chronic liver disease models. Methods: In vitro studies determined the kinase potency and selectivity of SRT-015, and cellular studies were used to demonstrate direct mechanisms of action. The cardiac hERG channel inhibition was assessed and PK determined in rodents and nonhuman primates. In vivo studies evaluated SRT-015 efficacy in rodent models of drug-induced hepatotoxicity (acetaminophen (APAP) overdose), alcohol-associated liver disease (ALD), metabolic-disease associated steatohepatitis (MASH) and cholestatic disease (bile duct ligation, BDL). Results: SRT-015, was demonstrated a selective ASK1 kinase, and SRT-015 treatment directly inhibited fibrosis, apoptosis and inflammation in activated human fibroblasts, hepatocytes and PBMCs, respectively without safety signals or hERG inhibition. Other ASK1 inhibitors had safety concerns or limited functional activity. Liver and kidney selective PK were observed for SRT-015 in all species evaluated. In vivo, SRT-015 treatment was efficacious in the acute mouse APAP overdose and ALD model significantly (P<0.05) decreasing serum ALT. Using a therapeutic diet-induced obesity (DIO)-MASH model with biopsy-verified fibrosis, SRT-015 treatment significantly (P<0.05) inhibited DIO-induced liver enzymes, hepatomegaly, fibrosis, inflammation, and apoptosis independent of body weight loss whereas treatment with selonsertib was ineffective. In a rat cholestatic model, SRT-015 treatment significantly (P<0.05) decreased fibrosis and stellate cell activation. Conclusions: These findings support SRT-015 as a potential therapeutic for human liver diseases of any etiology.

Regulation of the K+-Cl- cotransporter KCC2 is a critical determinant of the efficacy of inhibition in the central nervous system and KCC2 hypofunction appears at the root of several neurological disorders. Both BDNF-TrkB and NMDAR signaling regulate KCC2, but how they interact remains unknown. Here we show that these two signaling pathways act synergistically to differentially modulate KCC2 function and expression through post-translational regulation, via distinct Ca2+ signalling modes. Blocking ryanodine-dependent intracellular Ca2+ release prevented TrkB-, but not NMDAR-mediated downregulation. TrkB-signalling in absence of NMDAR activation modulated KCC2 function but not expression. In contrast, NMDAR activation induced KCC2 internalization dependent on extracellular Ca2+ influx. In turn, calpain-mediated KCC2 degradation, but not internalization, required Ca2+ influx through voltage-gated Ca2+ channels. While TrkB-activation potentiated the effect of NMDAR on KCC2, the reverse was not true. Yet, strong NMDAR activation was sufficient to cause TrkB-independent KCC2 downregulation. Finally, prolonged, but not short-term inhibition of KCC2 activity caused NMDAR-dependent KCC2 downregulation. These findings reveal, for the first time, that a co-transporter function can be regulated through other means than membrane expression: through a continuum of interwoven synergistic processes, from function to internalization to degradation, scaling with time and stimulus strength.

The excitability of afferents involved in nociceptive signaling reflects the interaction of several co-expressed membrane receptors. Current studies have shown that Toll-like receptor-4 (TLR-4) signaling can exacerbate excitation evoked by transient receptor potential vanilloid type 1 (TRPV1) activity, and this interaction plays a key role in driving and sustaining facilitated pain states. The mechanism by which this potentiated TRPV1 activity secondary to TLR-4 agonism occurs in sensory neurons remains unknown, although intracellular kinase activity is a strong candidate. To address this hypothesized linkage, neuronal cell cultures prepared from dorsal root ganglia (DRG) of male wildtype (WT) and Tlr4-/- mice were used to evaluate calcium transients of neurons after capsaicin administration in culture, pre-treated for 30 minutes with the TLR-4 agonist, lipopolysaccharide (LPS). TRPV1 protein expression at the neuron surface in cultured DRG cells with or without LPS treatment was quantified by flow cytometry assay. The roles of protein kinase A (PKA) and C were assessed using selective inhibitors (KT5720 for PKA and Chelerythrine chloride for PKC) applied to WT-DRG neurons or administered in vivo by intraplantar or intrathecal injection, prior to LPS and capsaicin administration. Behavioral effects of in vivo TRPV1 activation were assessed through paw flinch responses evoked by intraplantar capsaicin injection and by hind paw tactile thresholds measured by von Frey filaments. LPS incubation in cultured DRG neurons enhances the intensity of calcium influx following TRPV1 activation in WT but not Tlr4-/ cells. The augmented calcium influx evoked by capsaicin was prevented by the inhibition of PKA but not PKC. Similarly, mice treated with LPS in the hind paw displayed greater nociceptive responding after capsaicin and increased tactile allodynia. The facilitated component was prevented by the local pre-treatment with the PKA inhibitor. Correspondingly, lumbar spinal blockade of PKA resulted in temporary reversal of hyperalgesia induced by intrathecal LPS injection in mice. Together, these results demonstrate the relevance of TLR-4 in modulating the excitability of nociceptor signaling by regulating TRPV1, thereby influencing pain transmission through PKA signaling.

Background: Retrieval of adverse event reports based on coded drug-event co-occurrence enables large-scale pharmacovigilance analyses, but yields candidate reports rather than validated cases, risking misinterpretation if used alone. Aim: To develop and apply a framework for identification and characterization of clinically meaningful case series in pharmacovigilance. Methods: We conducted two case studies. The first developed and refined the framework in an information-rich setting, focusing on drug-induced impulsivity across selected drugs; the second tested its applicability in a more routine, information-poor setting, focusing on drug-induced suicidality. Results: In Case 1, non-relevant reports were frequent for drugs with uncertain evidence and negative controls ({approx}20-40%) compared to drugs with established causal roles (4%). The emerging framework assessed relevance based on exposure, event, drug-event relationship, and population. For suspected adverse drug reactions, relevant reports were further characterized by reporter suspicion and evidentiary qualifiers supporting or refuting causality; higher suspicion was associated with more supportive qualifiers. Applied to Case 2, the framework ruled out 69% of reports as non-relevant but highlighted substantial non-assessability (17%). Conclusions: In pharmacovigilance, retrieval is not equivalent to case identification. Relevance is question-specific and shaped by how reports are captured, processed, and retrieved. This can be especially critical for emerging or bias-prone safety questions. Transparent and reproducible case definition and adjudication are essential for interpretable analyses.

Confounding the treatment options available to patients with triple-negative breast cancer (TNBC) are not only its purported lack of hormone receptor and growth factor receptor targets (ER-/ PR-/ HER2-), but its enrichment in plastic and chemoresistant breast cancer stem cells (BCSCs). Although descriptions of non-canonical PR expression in TNBC are rife in the literature, only canonical PR is considered in the definition of TNBC and is used to determine therapeutic strategy, not least because the utility of non-canonical PR modulation in TNBC chemoresistance is largely unexplored and poorly understood. Here we document the expression of three non-canonical PRs and the canonical PR (PGR) phosphorylated at Ser345 (p-PGR S345) in a panel of TNBC and luminal breast cancer cell lines, and employ combined PR agonists and antagonists to investigate the influence of PR activity on TNBC cell viability and PI3K inhibitor cytotoxicity. To examine the contributions of non-canonical membrane-associated PRs mPR{beta} and PGRMC1, we tested the agonist Org OD 02-0, a synthetic progestin targeted to mPRs; the PGRMC1 antagonist Ag-205; and the antagonist SPA70 against the cytosolic/nuclear PXR, in the background of pan-PI3K inhibition with Buparlisib (BUP). We also reveal that combinations of agonists and antagonists targeted to canonical and non-canonical PRs robustly potentiate the cytotoxic effects of PI3K inhibition, and also exhibit significant cytotoxicity on their own. Using functional assays, flow cytometry, immunocytochemistry and protein expression analyses, we found that simultaneously perturbing PRs and inhibiting PI3K function resulted in significantly greater cell death than vehicle control or BUP alone, and reduced the proportion of ALDH1+ BCSCs in two TNBC cell lines. We conclude that four types of PR are tractable targets in TNBC which participate in cell viability and enhance chemotherapy-induced cytotoxicity, and should be re-evaluated in an evolving definition of this challenging disease.

Effective postoperative pain control is essential following laparoscopic cholecystectomy, yet the analgesic value of a standardised 150 mg preoperative dose of pregabalin has not been clearly established. This systematic review and meta-analysis synthesised evidence from seven randomised controlled trials published between 2008 and 2025 to evaluate the efficacy and safety of pregabalin when administered before surgery. Four trials reported 24-hour postoperative pain scores, and pooled analysis demonstrated that pregabalin significantly reduced pain compared with control (SMD = 0.80 lower; 95% CI, 1.42 to 0.18 lower; p = 0.01), although statistical heterogeneity was high (I-squared = 81%). Pregabalin also produced notable reductions in opioid consumption, including fentanyl (SMD = 1.24 lower; p = 0.002) and tramadol (SMD = 4.21 lower; p = 0.002), again with considerable variability across studies. Sedation was slightly increased but did not reach statistical significance, and there were no significant differences in postoperative nausea, vomiting, or headache. Sensitivity analyses supported the stability of these findings. Overall, the results indicate that a single 150 mg preoperative dose of pregabalin meaningfully reduces postoperative pain and opioid requirements following laparoscopic cholecystectomy while maintaining an acceptable safety profile, supporting its use as part of a multimodal analgesic strategy.

Decreases in brain pH are associated with numerous neurological and neuropsychiatric conditions yet the molecular mechanisms linking decreased brain pH with these disorders are incomplete. The ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission in the brain and are inhibited by extracellular protons; however, the proton sensitivity of the delta-glutamate receptor subclass of iGluRs is unknown. Using whole-cell patch-clamp recordings of serotonin neurons in mouse brain slices and activating alpha 1-adrenergic receptors to induce delta 1 glutamate receptor (GluD1R) current, we demonstrated that GluD1R current is inhibited by physiological drops in extracellular pH. Unlike other iGluRs, protons inhibited GluD1R current via a voltage-independent decrease in unitary current. Moreover, mice lacking GluD1R showed impaired behavioral responses to inhalation of CO2. Taken together, this study continues to expand on the growing body of evidence positing GluD1R as functional ion channels and suggests that GluD1R facilitate pH sensing in vivo.

Background. GLP-1 receptor agonist trials are tightly controlled: standardized titration, intensive dietary counseling, frequent in-person follow-up, and rigorous exclusion criteria. The real world is none of those things. In a U.S. telehealth GLP-1 program, diet engagement, exercise, medication choice, dose timing, and out-of-pocket cost vary substantially from patient to patient. Whether trial-level efficacy translates into the outcomes a patient and clinician will actually see is an open question, and the answer matters, because telehealth is now where most GLP-1 prescribing happens. Methods. We conducted a retrospective cohort study of 13,507 adults who used a single GLP-1 agent (tirzepatide or semaglutide) through the Mochi Health telehealth obesity program and had a documented six-month weight observation. The primary outcome was achievement of >=10% total body weight loss at six months. To address selection bias in the tirzepatide-semaglutide comparison, we used 1:1 nearest-neighbor propensity-score matching on age, sex, baseline BMI, baseline weight, and comorbid diabetes, hypertension, dyslipidemia, and prior bariatric surgery (recorded at intake), with a 0.25 SD caliper on the propensity logit. We drew a directed acyclic graph (DAG) with a clinical co-author to make the identifying assumptions explicit and to mark where unobserved variables (insurance, socioeconomic status, concomitant medications such as metformin) limit causal interpretation. We report multivariable predictors via logistic regression, compute an E-value for the matched contrast, and benchmark our point estimates against landmark RCT outcomes. Results. Overall, 59.1% of patients achieved >=10% loss at six months, with mean loss of 11.5% (median 11.3%). Threshold attainment was 86.6% at >=5%, 59.1% at >=10%, 27.5% at >=15%, and 9.1% at >=20%. The unadjusted tirzepatide-semaglutide response gap was +16.0 percentage points (68.8% vs 52.8%); after 1:1 propensity-score matching (3,480 pairs, all post-match |SMD| < 0.05) the gap was +18.1 percentage points (69.6% vs 51.6%, 95% CI +15.9 to +20.3). Matching on the measured covariates did not attenuate the advantage, indicating that selection on those characteristics does not explain it; the matched risk ratio was 1.35 (E-value 2.04). The gap was unchanged when a self-reported insurance indicator was added to the matching (+18.4 pp) and remained large (+14.2 pp) within patients who reached a therapeutic dose. Multivariable predictors of response were tirzepatide (OR 2.10, 1.95-2.26), female sex (OR 1.37, 1.20-1.56), and prior bariatric surgery (OR 1.36, 1.18-1.57); response was lower with comorbid diabetes (OR 0.84, 0.77-0.92) and, modestly, with higher baseline BMI per unit (OR 0.98, 0.97-0.99). Response varied by baseline BMI, from 58.0% in overweight patients (BMI <30) and a peak of 63.5% in Obese I to 52.4% in Obese III. Conclusions. Real-world response to GLP-1 therapy in a telehealth setting is meaningfully attenuated from RCT benchmarks but remains clinically substantial: roughly three in five patients reach the 10% threshold. The tirzepatide advantage over semaglutide is large and, notably, does not shrink under propensity-score matching on measured confounders, so it is not an artifact of the observed selection variables; an unmeasured confounder would need a risk-ratio association of about 2.0 with both drug choice and response to explain it away (E-value 2.04). The findings are observational, conditional on the DAG's identifying assumptions, and unmeasured confounders (insurance, socioeconomic status, concomitant medications) remain possible.

Ovarian disorders, including anovulation, primary ovarian insufficiency (POI), and polyendocrine metabolic ovarian syndrome (PMOS), affect millions of reproductive-age women worldwide; however, mechanistic studies of ovarian biology and pathophysiology remain challenging because current experimental approaches often lack selectivity, tunability, or physiological relevance. Genetically modified animal models are labor-intensive and irreversible; small molecules frequently exhibit off-target effects; and conventional antibodies have limited tissue penetration and restricted temporal control. Designed ankyrin repeat proteins (DARPins) represent a highly modular protein engineering platform with advantages in specificity, size, stability, and extracellular targeting, but their utility in reproductive biology remains largely unexplored. Here, we used epidermal growth factor receptor (EGFR)-targeting DARPins as a proof-of-concept platform to interrogate ovarian signaling during ovulation. Screening of engineered anti-EGFR DARPins identified SX-006, a bispecific tetravalent construct with robust cross-species EGFR binding and potent biological activity. Using an ex vivo murine ovulation system, SX-006 inhibited follicle rupture in a dose-dependent manner with IC50 of 1.21 M without overt cytotoxicity. Lower concentrations of SX-006 preferentially perturbed follicle rupture while largely preserving oocyte meiotic maturation and luteinization, suggesting differential sensitivity of ovulatory processes to extracellular EGFR blockade. Comparative transcriptomic analyses further revealed that extracellular EGFR blockade and small molecule-based intracellular EGFR kinase inhibition produce overlapping but also distinct transcriptional responses, supporting biologically distinct modes of ovulatory signaling pathway perturbation. Together, these findings establish DARPins as a selective, tunable, and physiologically relevant platform for studying ovarian signaling and provide proof-of-concept for extracellular receptor targeting in ovarian biology, infertility research, and non-hormonal contraceptive development. Summary sentenceAn engineered EGFR-targeting DARPin selectively inhibits ovulation through extracellular receptor blockade and establishes a versatile platform for investigating ovarian signaling and reproductive disorders.

Cav1.2 is an L-type voltage-gated Ca2+ channel (VGCC) that supports Ca2+ influx in response to membrane depolarization. Ca2+ entering via Cav1.2 alters gene expression, activates Ca2+-dependent enzymes and has been implicated in synaptic plasticity. ORL-1 is a Gi/o-coupled G protein-coupled receptor (GPCR) that is expressed in the peripheral and central nervous systems. Both Cav1.2 and ORL-1 are expressed in the hippocampus, where they have been implicated in learning and memory. It is well-documented that ORL-1 interacts with another VGCC, Cav2.2. However, less is known about potential interactions between Cav1.2 and ORL-1. Here, we examine the interplay between Cav1.2 (Cav1c, Cav2{delta}-1, Cav{beta}1) and ORL-1 co-expressed in tsA-201 cells by using biochemical, electrophysiological and confocal imaging analysis. Co-immunoprecipitations revealed that ORL-1 independently interacts with Cav1c and Cav2{delta}-1 subunits of the Cav1.2 channel complex. Electrophysiological recordings revealed that co-expression with ORL-1 reduced Cav1.2 peak current density without altering its biophysical properties. Acute perfusion with the ORL-1 receptor agonist nociceptin (1 M) did not alter Cav1.2 current density. Confocal imaging experiments revealed that ORL-1 significantly decreases Cav1.2 plasma membrane expression by disrupting forward trafficking. Interestingly, ORL-1 did not affect Cav1.2 endocytosis. Overall, our results demonstrate a previously unrecognized interaction between ORL-1 and Cav1.2 that alters Cav1.2 membrane expression without affecting biophysical properties.

PurposeCisplatin (CDDP) is the most active chemotherapy for ovarian cancer; primary or acquired resistance signals a poor prognosis. Nelfinavir (NFV), an HIV protease inhibitor, has demonstrated anti-tumor activity in multiple cancer models, but its interaction with CDDP in ovarian cancer has yet to be demonstrated. In this work, we addressed whether the combination of CDDP and NFV provides treatment advantage in platinum (Pt)-resistant ovarian cancer cells. MethodsDrug synergy between NFV and CDDP was assessed using cell vitality assays and Loewe additivity modelling. Apoptotic and pyroptotic signalling were evaluated by immunoblotting, mitochondrial membrane potential analysis, and lactate dehydrogenase (LDH) release, and caspase inhibition. Transcriptomic changes were assessed by bulk mRNA sequencing followed by differential gene expression analysis and gene set enrichment analysis. ResultsNFV synergized with CDDP to reduce the viability of Pt-resistant ovarian cancer cells, promoting a regulated lytic cell death phenotype involving apoptotic and pyroptotic features. Combination treatment induced caspase-8 and caspase-3 activation, and downstream gasdermin E (GSDME) processing. Inhibition of caspase-3 significantly attenuated cell death, and caspase-8 inhibition rescued viability and prevented Bid cleavage, caspase-3 activation, and GSDME cleavage. These effects occurred in the context of enhanced endoplasmic reticulum stress, increased DNA damage with reduced DNA repair, and impaired Akt-driven survival signalling. ConclusionsOur findings establish that NFV synergizes with CDDP in killing Pt-resistant ovarian cancer cells by promoting a caspase-8-dependent apoptotic-to-secondary pyroptotic response, supporting further investigation of NFV as a potential drug to be repurposed to increase the efficacy of Pt-based therapy.

Background. Compounded tirzepatide is prescribed at scale as a cheaper substitute for branded Mounjaro and Zepbound, yet the cost case is almost always built by setting one compounded price against one branded list price. That framing ignores the question that actually decides the answer: cheaper than which branded price the patient can reach. Branded tirzepatide is now sold at sharply different tiers, namely insurance copay (often $25-$150/month), LillyDirect Self Pay ($299-$449/month), and retail cash price ($1,000-$1,200/month). Whether compounded saves money turns entirely on which of these a given patient faces. A second open question is whether the two formulations even produce comparable effectiveness, since observed differences may reflect selection on insurance, baseline characteristics, and adherence rather than the drug. Methods. We conducted a retrospective cohort study of tirzepatide users in the Mochi Health telehealth program, classified by formulation from their refills as branded-only (Mounjaro/Zepbound; 6,238), compounded-only (71,683), or switchers (4,996); switchers were excluded from the formulation contrast. Among single-formulation patients with a documented six-month weight observation, the analytic cohort was 7,271 (869 branded, 6,402 compounded). The primary outcome was six-month percent body weight loss; the secondary outcome was >=10% response. We used 1:1 nearest-neighbor propensity-score matching (0.25 SD caliper) on baseline covariates only - age, sex, baseline BMI, baseline weight, comorbid diabetes, hypertension, dyslipidemia, prior bariatric surgery, and self-reported insurance coverage - deliberately excluding post-treatment variables such as adherence and time in program, which are mediators of the formulation effect. We pre-specified an equivalence margin of +/-2 percentage points on mean loss and tested equivalence with two one-sided tests (TOST). A directed acyclic graph (DAG) makes the identifying assumptions explicit; metformin use could not be reliably ascertained and is treated as an unmeasured confounder. The cost comparison reports the savings or premium of compounded versus branded under five branded price scenarios: retail list, LillyDirect Self Pay (two dose tiers), and insurance copay (typical and low end). It is a cost comparison (cost-minimization under demonstrated similar effectiveness), not a formal cost-effectiveness analysis: we computed no ICER, QALY, or discounting. Results. Branded and compounded patients had similar outcomes even before adjustment (mean loss 11.7% vs 11.5%; >=10% response 60.9% vs 58.8%). The largest baseline difference between the groups was insurance coverage (branded patients far more likely insured; standardized mean difference 0.67), which matching balanced to 0.01. After 1:1 matching (718 pairs, all |SMD| < 0.04), mean loss was 11.4% vs 11.4% (difference +0.08 pp, 95% CI -0.70 to +0.80) and >=10% response 59.3% vs 57.2% (difference +2.1 pp, 95% CI -3.1 to +7.1). The two formulations were statistically equivalent within the pre-specified +/-2 pp margin (TOST p < 0.001). Cost depends on the branded scenario: compounded saves $6,000 over six months versus retail list price, $1,494 versus LillyDirect maintenance-dose (5-15 mg) Self Pay, and $594 over a low-dose (2.5 mg) LillyDirect prescription, while it costs $300 more than branded under a typical insurance copay ($150/month) and is more expensive still at lower copays (savings turn negative below $200/month). Conclusions. Branded and compounded tirzepatide were statistically equivalent in six-month effectiveness within a pre-specified +/-2 pp margin, so the choice between them is essentially a cost decision - and that cost advantage is real but conditional on the branded price the patient can access. It is large against retail list price and shrinks to zero or reverses against LillyDirect Self Pay or a low insurance copay. Whether compounded is the lower-cost choice for an individual patient is, therefore, a question about which price tier that patient faces.

An acetaminophen (APAP) overdose is the leading cause of drug-induced hepatotoxicity and acute liver failure (ALF) in the United States. While N-acetylcysteine (NAC), is highly effective when administered early after an overdose, its efficacy decreases with delayed administration. Since most patients present late to the clinic, there is an urgent need for novel late-acting therapeutic options to prevent progression to ALF. We previously demonstrated the benefit of delayed activation of the Adenosine A2B Receptor (A2BAR) in attenuating APAP-induced hepatotoxicity and this study focuses on its effects on liver recovery after injury. Fasted male C57BL/6J mice were treated with 300 mg/kg APAP, followed by activation of A2BAR 6 or 9 h later and sacrifice 24, 48 or 72 h post-APAP with evaluation of liver injury, the innate immune response and liver regeneration. Delayed activation of A2BAR significantly enhanced liver recovery, with accelerated repopulation of the liver by Kupffer cells, increased macrophage migration to the necrotic areas and their faster resolution. A2BAR activation also upregulated lipid metabolism related genes in non-parenchymal cells and cell proliferation and metabolism genes in hepatocytes. Remarkably, genes such as Cidec and Plin2, crucial for lipid droplet formation, were upregulated, indicating that A2ABR activation enhances lipid metabolism which plays a key role in providing energy for liver regeneration. Overall, these findings highlight the potential of A2BAR activation not only in protecting against liver injury, but also in promoting and accelerating liver regeneration by modulating the innate immune responses and metabolic pathways.