Journal of Pharmacology and Experimental Therapeutics最新文献

Environmental cues that have been associated with drug-taking can evoke drug-craving and drug-seeking and drive relapse. Using the New Response Acquisition procedure, we evaluated the extent to which activation of delta opioid receptors (DORs) changes responding for cocaine-associated stimuli. We hypothesized that activation of DORs, either directly via agonists or indirectly via protected concentrations of endogenous enkephalin peptides, would increase the conditioned reinforcing effects of cues. First, animals undergo Pavlovian conditioning during which rats received 5 infusions of cocaine (0.32 mg/kg/inf) and either paired or unpaired presentations of a stimulus (light + tone) per day for 10 days. Next, nosepokes were added to the operant chamber and rats were allowed to respond for presentations of cocaine-associated stimuli (acquisition). Consistent with previous findings, animals assigned to paired Pavlovian conditioning emitted more responses for cue presentations than animals assigned to the unpaired control. Interestingly, acute administration of SNC80 (DOR agonist; 3.2 mg/kg s.c.) on acquisition session 4 led to robust increases in responding for the cocaine-paired cues in the paired, but also increased responding for cues in rats assigned to unpaired and saline control groups. Further, the enkephalinase inhibitor RB101 (10 mg/kg intravenous), which maintains extracellular concentrations of enkephalins, increased active responding in a DOR-dependent manner. These data suggest that activation at DORs influences behaviors maintained by cues and sheds light on the neurobiology underlying the conditioned reinforcing effects of drug-associated stimuli. SIGNIFICANCE STATEMENT: We used a more rigorous test of conditioned reinforcement to show that activation of delta opioid receptors increases the reinforcing effects of cocaine-paired cues, depending on conditioning history, which implicates the delta opioid receptor system as a target to reduce relapse.

Efficient delivery of small interfering RNA (siRNA) remains a major challenge in gene therapy, particularly due to poor cellular uptake, enzymatic degradation, and endosomal entrapment of the cargo. Cell penetrating peptides (CPPs) offer a promising strategy for intracellular delivery of nucleic acids; however, peptide-based gene delivery carriers possess limited nucleic acid condensation capability, demonstrating reduced transfection efficacies in mammalian cells. This study aimed to enhance siRNA delivery efficacies of CPP-based siRNA therapeutics by combining nucleic acid condensation efficacies of methylated protamine with the cell permeation capabilities of cyclic peptides to improve physiological stability, cellular uptake, and gene silencing efficacies in HER2⁺ breast cancer cells. Cyclic CPPs (cCPPs) of different cationic and amphipathic characters (namely, cTAT, cKALA, and cC105Y) were synthesized by solid phase peptide synthesis. Methylated protamine/siRNA complexes of net neutral nanoparticles (NNPs) obtained at nitrogen-to-phosphate ratio of 1 were functionalized with cCPPs at various cCPP/siRNA w/w ratios, and the sizes and net charges of the formulated nanoparticles were analyzed using dynamic light scattering and a zeta potential instrument, respectively. cCPP-functionalized NNPs demonstrated improved nucleic acid condensation efficacy and protection against enzymatic degradation compared with bare NNPs. cCPP-NNPs formulated using various types of peptides overall demonstrated superior siRNA transfection efficacies with ∼60% HER2 gene silencing efficacies in HER2⁺ breast cancer cells. cC105Y-NNPs particularly showed improved physiological stability and cellular uptake compared with the other cCPP-functionalized nanoparticles. Endosomal escape remained a limiting factor in the gene expression efficacies of cCPP-NNPs, and incorporation of an endosome-disrupting agent improved HER2 gene knockdown efficacies (∼80%) to levels that were comparable to the Lipofectamine control. Furthermore, the potential of cCPP-NNPs for simultaneous knockdown of HER2 and HER3 was demonstrated to improve the anticancer efficacies of the nanoparticle for HER2⁺ breast cancer treatment. SIGNIFICANCE STATEMENT: Cyclic cell penetrating peptide-functionalized nanoparticles with improved physiological stability and optimized nucleic acid condensation and release efficacies formulated by simple deposition of cationic peptides on protamine small interfering RNA complexes demonstrate superior gene knockdown and anticancer efficacies in breast cancer cells.

The clinical effectiveness of peptide and protein therapeutics is often limited by their short circulating half-life, necessitating frequent injections. Therefore, half-life extension strategies have emerged as centerpieces in biopharmaceutical development to enhance therapeutic efficacy, reduce dosing frequency, and improve patient outcomes. A variety of approaches have been being investigated and used to prolong systemic exposure of protein drugs. Increasing hydrodynamic volume and enabling neonatal Fc receptor recycling are 2 mechanisms that are being applied to extend the half-life of many therapeutic proteins. In this review, we discuss elimination mechanisms of protein therapeutics, underlying mechanisms and strategies for their half-life extension, impact of half-life extension on primary pharmacokinetic parameters, and critical factors to be considered to choose effective half-life extension strategy. Despite these advances, challenges remain in balancing half-life extension with biological activity, stability, and manufacturability. Ongoing research aims to optimize these technologies to meet the growing demand for long-acting biologics in chronic disease management. As half-life extension continues to evolve, it holds promise not only in improving therapeutic performance but also in expanding the applicability of protein drugs across a broader range of clinical indications. SIGNIFICANCE STATEMENT: The clinical utility of many protein and peptide therapeutics is limited by insufficient circulation time. Half-life extension strategies such as PEGylation, albumin fusion, and Fc fusion have demonstrated benefits clinically and permit extended dosing windows.

Adiponectin receptor (AdipoR) agonists protect against glomerular inflammation and injury in obesity-related glomerulopathy (ORG), but their molecular mechanisms remain unclear. Given the implication of the ceramide signaling pathway in the pathogenesis of ORG, the present study tested whether AdipoR agonists target acid ceramidase (AC) to inhibit NLRP3 inflammasome activation in podocytes, thereby blocking glomerular inflammation and injury during obesity. Confocal microscopy showed that adiponectin attenuated visfatin-induced NLRP3 inflammasome activation and IL-1β-containing multivesicular body (MVB) formation in podocytes. Nanoparticle tracking analysis revealed that adiponectin suppressed visfatin-induced extracellular vesicle release, an effect dependent on AC activity. Structured illumination microscopy demonstrated that visfatin reduced lysosome-MVB interaction in podocytes, which was restored by adiponectin via enhancement of TRPML1 channel-mediated Ca²⁺ release. The rescue of lysosome-MVB interaction and TRPML1 channel activity by adiponectin was mimicked by the AC enhancer but interfered with by the AC inhibitor. In vivo, high-fat diet (HFD) treatment induced NLRP3 inflammasome activation and T cell infiltration in glomeruli and increased urinary extracellular vesicle excretion in mice, which were exaggerated by podocyte-specific Smpd1 gene (gene code of acid sphingomyelinase) overexpression in Smpd1^trg/Podo^cre mice compared with WT/WT mice. AdipoRon, a synthetic AdipoR agonist, reduced HFD-induced glomerular inflammation in both WT/WT and Smpd1^trg/Podo^cre mice, but its effect was blocked by AC inhibition. Moreover, podocyte-specific Smpd1 gene overexpression aggravated HFD-induced podocyte injury, proteinuria, and glomerular sclerosis, which were mitigated by AdipoRon in an AC-dependent manner. Additionally, we found that the protective actions of AdipoRon may be mainly attributed to the activation of AdipoR1, but not AdipoR2. Taken together, our findings suggest that AC activation mediates the protective effects of AdipoR agonists against glomerular inflammation and injury in ORG, highlighting AC as a potential therapeutic target. SIGNIFICANCE STATEMENT: This study identifies acid ceramidase as a key mediator of adiponectin receptor agonist action in podocytes, linking its activation to suppression of NLRP3 inflammasome and extracellular vesicle release, and highlighting a novel therapeutic target in obesity-related kidney disease.

Human aging is driven by several interconnected hallmarks, including genomic instability, mitochondrial dysfunction, and cellular senescence, which collectively underlie pathologies such as neurodegeneration and metabolic decline. Despite advances in identifying senescence-associated biomarkers and pathways, conventional antiaging compounds such as resveratrol and fisetin, lack regulatory approval owing to insufficient evidence from large-scale trials. Drug repurposing provides a cost-efficient strategy to target aging pathways by leveraging existing pharmacologic safety profiles. Erythropoietin (EPO) exemplifies this approach, demonstrating pleiotropic antiaging effects through modulation of cell survival pathways and tissue-protective mechanisms. Recent advancements in nonhematopoietic EPO derivatives, such as carbamylated EPO, further unlock its development potential by decoupling therapeutic benefits from erythropoietic activity. This review analyzes EPO molecular antiaging mechanisms and clinical applications in age-related diseases (2015-2025), focusing on multiorgan systemic effects and derivative development beyond anemia. SIGNIFICANCE STATEMENT: This review highlights erythropoietin (EPO) as a promising repurposed drug for combating aging, targeting hallmarks such as oxidative stress and cellular senescence. Crucially, nonhematopoietic EPO derivatives circumvent traditional safety risks while retaining multipathway protective effects in brain, cardiovascular, and metabolic tissues. By leveraging established pharmacology, EPO offers a cost-efficient strategy to advance aging interventions, addressing age-related pathologies beyond anemia.

Ocular drug delivery faces significant challenges because of the eye's complexity and anatomical barriers, such as the cornea, conjunctiva, and blood-retinal barrier, which limit drug penetration and bioavailability. Recent advances in nanotechnology-based drug delivery have led to the development of innovative delivery platforms, enabling targeted, sustained, and minimally invasive delivery for ocular diseases and injuries. This review outlines the recent advances in nanosystems-based ocular drug delivery and highlights the latest progress in targeting technologies based mainly on preclinical studies and selected clinical trial data. It covers a variety of nanosystems, including organic nanoparticles (NPs) such as liposomes, nanomicelles, nanosuspensions, nanoemulsions, dendrimers, and nanofibers. Additionally, it addresses inorganic NPs, which include gold NPs, silver NPs, silica NPs, and carbon nanotubes. Besides, we summarize the clinical challenges and regulatory aspects in nanotechnology-based ocular drug delivery. Finally, inspired by current advances and therapeutic strategies, we provide an insight into clinical applications and future research directions on nanosystems-based drug delivery. We highlight the need to overcome the challenges of using nanosystems in ocular drug delivery and fill the knowledge gap on their nanotoxicity and future development. SIGNIFICANCE STATEMENT: This review highlights recent advances in nanosystem applications for ocular drug delivery, summarizes up-to-date clinical trials utilizing nanosystems for ocular drug delivery, and discusses clinical challenges and directions for future development.

Disordered energy regulation within the kidney represents an important therapeutic target to reduce the severity of acute kidney injury and subsequent fibrosis. AMP-activated protein kinase (AMPK) is stimulated in situations of cellular energy deprivation to act as a key regulator of cellular and systemic energy metabolism. AMPK activation has been shown to be protective against renal injury and fibrosis in numerous experimental studies using metformin and aminoimidazole-4-carboxamide ribonucleotide. However, studies with these traditional AMPK activators are limited by these agents being indirect activators of AMPK, with unwanted off-target effects that may limit their use. Novel AMPK activators represent a promising new therapy in kidney protection, as well as in a range of other chronic diseases. AMPK phosphorylates multiple targets to regulate numerous pathways, thereby enabling multiple mechanisms to reduce kidney injury. This review outlines important mechanisms of renal injury and fibrosis as well as the current landscape of novel AMPK activators. It outlines experimental evidence for mechanisms of novel AMPK activators and how these relate to injury and fibrosis within the kidney. Finally, it discusses the potential of these agents, as well as current challenges in their development. SIGNIFICANCE STATEMENT: Multiple studies have identified dysregulated energy metabolism as a treatment target for kidney disease, revealing novel AMP-activated protein kinase (AMPK) activators as a promising new therapy to address this opportunity for protection against kidney injury and fibrosis. Despite this promise, novel AMPK activators are yet to find a clinical role for kidney disease or other conditions. Barriers to be considered in future studies include concerns about cardiac hypertrophy and oncogenesis as well as elucidation of precise pharmacokinetic properties. Nonetheless, the large volume of beneficial preclinical data for kidney health provides motivation for future studies to address these needs.

S100A4, a member of the S100 family of calcium-binding proteins, acts as a damage-associated molecular pattern with a central role in modulating inflammatory and fibrotic responses. Upon extracellular release, S100A4 engages receptors such as toll-like receptor 4, triggering signaling cascades that amplify proinflammatory cytokine production and promote fibrotic tissue remodeling, positioning it as a promising therapeutic target. This study describes the development and characterization of CAL101, a humanized IgG4 monoclonal antibody, which binds with high affinity to the S100A4 target-binding interface. CAL101 exhibits strong cross-species reactivity, effectively binding S100A4 from human, cynomolgus monkey, mouse, and rat. Functional assays demonstrate that CAL101 inhibits toll-like receptor 4 and transforming growth factor β pathway activation in reporter cell lines and decreases cytokine release in human monocytes and whole blood cell cultures. These findings support continued development of CAL101 as a therapeutic candidate for fibrotic and chronic inflammatory diseases. A recently completed phase I trial (ClinicalTrials.gov ID NCT05965089) established the safety, pharmacokinetic, and immunogenicity profile of CAL101. A phase II trial in patients with idiopathic pulmonary fibrosis has been initiated (ClinicalTrials.gov ID NCT06736990). SIGNIFICANT STATEMENT: This article presents the development and characterization of CAL101, a first-in-class humanized IgG4 antibody that neutralizes S100A4 by blocking its receptor interactions. CAL101 suppresses inflammatory and fibrotic signaling and is currently in phase II trial for idiopathic pulmonary fibrosis.

Severe asthma is characterized by persistent airway inflammation and structural remodeling, including mucus accumulation, epithelial thickening, and subepithelial fibrosis, which are often refractory to conventional therapies. Group 2 innate lymphoid cells (ILC2s) contribute to these pathological changes by producing large amounts of interleukin-5, interleukin-13, and amphiregulin. Although cell cycle regulators have been implicated in immune cell proliferation, their role in ILC2-driven asthma pathogenesis remains unexplored. Here, we identified the cyclin-dependent kinase (CDK) 4/6-ILC2 axis as a previously unrecognized driver of airway remodeling in severe asthma. Using an ovalbumin (OVA)-induced mouse model of severe asthma, we demonstrated that (1) CDK4⁺ and CDK6⁺ cells were elevated by 4.0- and 4.5-fold, respectively, in the lungs; (2) treatment with the CDK4/6 inhibitor palbociclib reduced fibrosis and ILC2 expansion by 77% and 87%, respectively; (3) increased ILC2s in the lungs showed high gene expression levels of CDK4, CDK6, and profibrotic factors, including fibroblast growth factor 2, fibroblast growth factor 23, collagen (COL) 4A2, COL10A1, and COL18A1; (4) thymic stromal lymphopoietin stimulation enhanced CDK4/6 protein expression in ILC2s, leading to their proliferation; and (5) palbociclib significantly inhibited the proliferation of ILC2s, at least in part by suppressing retinoblastoma phosphorylation. These findings establish CDK4/6 as a novel molecular pathway regulating ILC2-mediated airway remodeling and highlight its inhibition as a promising therapeutic approach for severe asthma. SIGNIFICANCE STATEMENT: Although cell cycle regulators have been implicated in immune cell proliferation, their role in group 2 innate lymphoid cell-driven asthma pathogenesis remains unexplored. Here, we identified the cyclin-dependent kinase 4/6-group 2 innate lymphoid cell axis as a previously unrecognized driver of airway remodeling in severe asthma.