Biology subjects

Reznikov, L.

Publications and source records attributed to Reznikov, L..

5 recordsLinked to original sources

bioRxiv2026

AB-Free Kava and its Kavalactones Suppress Cigarette Smoke- and Lipopolysaccharide-Induced Lung Inflammation: Efficacy and Mechanisms

Cigarette smoke-induced lung inflammation is a central driver of pulmonary diseases. The limited efficacy of current anti-inflammatory agents underscores the need for structurally novel therapeutics with distinct mechanisms. We recently demonstrated that AB-free kava, a flavokavains A/B-depleted formulation from Piper methysticum containing six major kavalactones, effectively suppresses cigarette smoke-induced lung inflammation in mice. This study aims to identify the bioactive constituent(s) and elucidate underlying mechanisms. These kavalactones revealed a clear structure-activity relationship in suppressing lipopolysaccharide (LPS)-stimulated prostaglandin E2 (PGE2) production in macrophages with desmethoxyyangonin (DMY) as the most potent kavalactone whereas dihydrokavain (DHK, a structurally similar analog) with minimal activity. DMY also effectively reduced LPS-induced interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-) production while DHK was ineffective. Mechanistically, DMY, but not DHK, attenuated COX-2 induction and reduced phosphorylation of cAMP response element-binding protein (CREB). Pharmacological inhibition of protein kinase A (PKA) similarly reduced p-CREB, COX-2 and PGE2, supporting a PKA-dependent CREB/COX-2 signaling in mediating PGE2 suppression while these effects were independent of nuclear factor kappa B (NF-{kappa}B) and activator protein 1 (AP-1) signaling. Similar results were observed for DMY and DHK in attenuating cigarette smoke condensate-induced proinflammatory pathways and PGE2 production. Consistently, DMY demonstrated significant in vivo efficacy in suppressing cigarette smoke-induced lung inflammation while DHK was not effective. Interestingly, dihydromethysticin (DHM) demonstrated the greatest in vivo anti-inflammatory efficacy, although it only exhibited moderate in vitro potency, likely due to its superior bioavailability over DMY. Concordantly, cigarette smoke exposure elevated p-CREB and COX-2 expressions in mouse lungs, which were attenuated by AB-free kava and its bioactive kavalactones with the extent of suppression correlating with their in vivo anti-inflammatory efficacy. DHM effectively suppressed LPS-induced neutrophil accumulation in mouse lungs as well. Collectively, these studies identify bioactive kavalactones in AB-free kava that suppress cigarette smoke- and LPS-induced lung inflammation through the modulation of the PKA/CREB/COX-2 signaling axis, providing a foundation for developing structurally distinct anti-inflammatory agents, particularly targeting smoke-induced inflammation and associated pulmonary diseases.

immunology↗

bioRxiv2025

AB-Free Kava Suppresses Tobacco Smoke-Induced CREB Phosphorylation in the Mouse Cerebellum

IntroductionOur recent studies revealed the potential of AB-free kava as a novel therapeutic candidate against tobacco use disorder while the underlying mechanism remains to be elucidated. The cerebellum region in the brain has recently been reported to be involved in tobacco smoke withdrawal. The cAMP response element-binding protein (CREB) activation via phosphorylation has also been reported to contribute to substance abuse, including tobacco use disorder. Our early pre-clinical work revealed the potential of AB-free kava to suppress tobacco smoke-induced CREB activation in lung tissues. MethodsIn this study, we investigated the impact of tobacco smoke exposure on the levels of phosphorylated CREB (p-CREB) in the mouse cerebellum and evaluated the effects of AB-free kava. ResultsFour different regimens of tobacco smoke exposure consistently increased the levels of p-CREB in the cerebellum. Importantly, AB-free kava effectively suppressed tobacco smoke-induced increase in p-CREB to levels comparable to mice without tobacco smoke exposure. ConclusionsCREB activation in the cerebellum is a potential mechanism involved in tobacco use disorder, and our data provide preliminary evidence for the protective potential of AB-free kava.

molecular biology↗

bioRxiv2024

Brain-body circuit by which midbrain dopamine neuronal activity modulates splenic immunity

Midbrain dopamine neurons are well-known to shape central nervous system function, yet there is growing evidence for their influence on the peripheral immune system. Here we demonstrate that midbrain dopamine neurons form a circuit to the spleen via a multi-synaptic pathway from the dorsal vagal complex (DVC) through the celiac ganglion. Midbrain dopamine neurons modulate the activity of D1- and D2-like dopamine receptor-expressing DVC neurons. In vivo activation of midbrain dopamine neurons induced dopamine release in the DVC and increased immediate early gene expression in both the DVC and celiac ganglion. Activation of this midbrain-to-spleen circuit reduced spleen weight and decreased naive CD4+ T-cell populations without affecting total T-cell numbers. These findings unveil a functional midbrain- DVC-celiac ganglion-spleen pathway, through which midbrain dopamine neurons modulate splenic immunity. These novel insights into the neural regulation of the immune system have important implications for diseases involving altered dopamine neurotransmission and highlight potential targets for immunotherapeutic interventions.

neuroscience↗

bioRxiv2024

AB-free kava enhances resilience against the adverse health effects of tobacco smoke in mice

Tobacco smoke remains a serious global issue, resulting in serious health complications, contributing to the onsets of numerous preventive diseases, and imposing significant financial burdens. Despite regulatory policies and cessation measures aimed at curbing its usage, novel interventions are urgently needed for effective damage reduction. Our preclinical and pilot clinical studies showed that AB-free kava has the potential to reduce tobacco smoke-induced lung cancer risk, mitigate tobacco dependence, and reduce tobacco use. To understand the scope of its benefits in damage reduction and potential limitations, this study evaluated the effects of AB-free kava on a panel of health indicators in mice exposed to 2 - 4 weeks of daily tobacco smoke exposure. Our comprehensive assessments included global transcriptional profiling of the lung and liver tissues, analysis of lung inflammation, evaluation of lung function, exploration of tobacco nicotine withdrawal, and characterization of the causal PKA signaling pathway. As expected, Tobacco smoke exposure perturbed a wide range of biological processes and compromised multiple functions in mice. Remarkably, AB-free kava demonstrated the ability to globally mitigate tobacco smoke-induced deficits at the molecular and functional levels with promising safety profiles, offering a unique promise to mitigate tobacco smoke-related health damages. Further pre-clinical evaluation and clinical translation are warranted to fully harness the potential of AB-free kava in combating tobacco smoke-related harms. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/599576v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1f6ee4corg.highwire.dtl.DTLVardef@96e062org.highwire.dtl.DTLVardef@16579a0org.highwire.dtl.DTLVardef@1140a8e_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2020

Modulation of Transient receptor potential melastatin 3 by protons through its intracellular binding sites

Transient receptor potential melastatin 3 channel (TRPM3) is a calcium-permeable nonselective cation channel that plays an important role in modulating glucose homeostasis in the pancreatic beta cells. However, how TRPM3 is regulated under physiological and pathological conditions is poorly understood. In this study, we found that both intracellular and extracellular protons block TRPM3 through its intracellular binding sites. We demonstrated that external protons indirectly block TRPM3, whereas internal protons inhibit TRPM3 directly with an inhibitory pH50 of 6.9 {+/-} 0.11. We identified three titratable residues, D1059, D1062, and D1073, at the inner vestibule of the channel pore that contribute to pH sensitivity. The mutation of D1073Q reduces TRPM3 current intensity and pH sensitivity; Replacement of Asp 1073 by Gln 1073 changes the reduction of TRPM3 outward current by low external pH 5.5, from 62 {+/-} 3 % in WT to 25 {+/-} 6.0 % in D1073Q. These results indicate that D1073 is not only essential for intracellular pH sensitivity, but it is also crucial for TRPM3 channel gating. In addition, a single mutation of D1059 or D1062 enhances pH sensitivity. In summary, our findings provide a novel molecular determinant for pH regulation of TRPM3. The inhibition of TRPM3 by protons may indicate an endogenous mechanism governing TRPM3 gating and its physiological/ pathological functions.

pharmacology and toxicology↗