Molecular Pharmacology最新文献

Histone deacetylase (HDAC)6 is a broadly expressed class IIb HDAC that regulates cytoskeletal dynamics and some nuclear processes. Previously research has shown that HDAC6 enzymatic inhibition has analgesic properties in models of chemotherapy-induced peripheral neuropathy. Here, we evaluated the effects of genetic and pharmacologic inhibition of HDAC6 on the development of sensory hypersensitivity in mouse models of peripheral nerve injury and peripheral inflammation. Daily administration of the peripherally restricted HDAC6 inhibitor, ACY1215 (Regenacy Pharmaceuticals, Inc), attenuated mechanical allodynia in the von Frey assay within 2 days of treatment initiation, with no signs of analgesic tolerance after 21 days of administration. We observed a similar antiallodynic effect across the implemented injury models after conditionally knocking down Hdac6 in the adult dorsal root ganglia (DRGs). Bioinformatic analysis of whole-transcriptome RNA-sequencing data predicted that ACY1215 treatment predominantly attenuated proinflammatory mechanisms, such as the suppression of immune cell infiltration into the DRG after injury. Accordingly, we demonstrated a reduction in the expression of various immune cell markers in the DRG after pharmacologic and genetic HDAC6 inhibition in both neuropathic and inflammatory pain models. We identified a direct relationship between Ccl5/Ccr5 and Hdac6 downregulation, as well as reduced hypersensitivity after hind paw CCL5 administration upon Hdac6 knockdown in the DRG. Our findings highlight that peripheral inhibition of HDAC6 ameliorates sensory hypersensitivity in models of postoperative inflammatory and neuropathic pain through mechanisms beyond reduction of tubulin deacetylation. SIGNIFICANCE STATEMENT: Recent studies highlight the role of histone deacetylase (HDAC)6 in chemotherapy-induced peripheral neuropathy, through mechanisms of action including tubulin acetylation and mitochondrial trafficking. In this study, various murine models of acute and chronic pain are applied to show that inhibition of HDAC6 activity in the periphery, using the clinically tested ACY1215 compound, and genetic inactivation of the Hdac6 gene in the dorsal root ganglia, alleviated mechanical hypersensitivity in male and in female mice through mechanisms that include targeting injury-induced inflammation.

Various types of drugs can affect serum urate levels as side effects. Although these drugs are used to treat different diseases, they might share a structural component that acts on a common target to affect urate levels. Human urate transporter 1 (URAT1) plays an essential role in urate reabsorption at the renal proximal tubule and thus might be a common target for drugs that can affect serum urate levels. Our aim was to elucidate the structural requirements for a compound to show activity toward URAT1 and to identify clinically used drugs that can affect URAT1 activity. Our search was based on structural similarities in the compounds. [¹⁴C]Urate uptake by URAT1-expressing human embryonic kidney 293 (HEK-hURAT1) cells in the presence of an analog of a small molecule with known URAT1 activity suggested that structural moieties of salicylic acid can increase URAT1 cis-inhibitory activity. Therefore, we searched a database for drugs with substructures similar to salicylic acid. We were able to predict some types of loop diuretics, statins, and angiotensin receptor blockers as drug candidates that might affect URAT1. In addition, we found that glinides inhibit urate uptake by HEK-hURAT1 cells. Three glinides (nateglinide, mitiglinide, and repaglinide) all inhibited urate uptake by HEK-hURAT1 cells concentration-dependently (IC₅₀: nateglinide, 39 μM; mitiglinide, 63 μM; repaglinide, 3.9 μM). Furthermore, glinides also showed trans-inhibition activity in URAT1-expressing Xenopus oocytes pretreated with the glinides. These findings suggest that glinides sharing a salicylic acid-like substructure might affect serum urate level by acting on URAT1. SIGNIFICANCE STATEMENT: Some types of loop diuretics, statins, angiotensin receptor blockers, and glinides were predicted to affect URAT1, based on their chemical structural similarity to salicylic acid, the structure of which allows it to interact with URAT1. Glinides in particular showed cis- and trans-inhibitory activity toward URAT1.

CXCR4 is an important therapeutic target for hematopoietic stem cell mobilization, which enhances the success of autologous stem cell transplantation for treating blood cancers such as lymphomas and myeloma. As CXCR4 has been shown to be involved in various inflammatory diseases, cancer progression, and cell entry by the human immunodeficiency virus, understanding the molecular mechanism of CXCR4 inhibitors has potential implications in a wide area of diseases. Here, we present an exploratory study which involves the molecular pharmacological characterization of TG-0054 (burixafor, GPC-100), a clinical candidate for hematopoietic stem cell mobilization. TG-0054 inhibited CXCL12 binding at CXCR4, and antagonized both Gα_i and β-arrestin2 recruitment as well as the downstream Gα_i-attenuation of cAMP signaling pathway, with pIC₅₀ of 7.7, 8.0, and 7.9, respectively. Compared with the clinically used antagonist AMD3100 and the prototypical inverse agonist Isothiourea-1t (IT1t), TG-0054 displayed a unique pharmacological profile. Like IT1t, TG-0054 inhibited the constitutive Gα_i signaling of CXCR4. However, in contrast to IT1t and other reported inverse agonists, TG-0054 was not able to induce monomerization of CXCR4 oligomeric complexes. Considering the unique properties of TG-0054 on CXCR4, TG-0054 is an interesting tool compound for studying the relevance of inverse agonism as well as CXCR4 monomerization in various pathologies. SIGNIFICANCE STATEMENT: CXCR4-targeted therapeutics hold important potential for the treatment of blood cancers. TG-0054 has inverse agonistic properties and is a non-CXCR4-monomerizing small molecule antagonist, unlike other well studied CXCR4 small molecule antagonists.

Multiple sclerosis (MS) is growing in prevalence; yet, treatments that can reverse the progression of the disease are still needed. One strategy that has shown promise for reversing MS is remyelination by inhibiting the M1 receptor, a member of the muscarinic acetylcholine receptor (mAChR) family. Antagonizing the M1 mAChR is believed to be the mechanism by which clemastine, a developing drug that has been observed to enhance myelination in animal studies and phase II clinical trials, elicits its myelination-promoting effects. Recent studies have indicated that blocking M1 mAChR may promote oligodendrocyte differentiation via the extracellular signal-regulated kinase pathway, modulating Ca²⁺ concentration oscillations, and cross-talking with N-methyl-d-aspartate and Notch-1 receptors. However, clemastine has recently been found to accelerate disability in patients with MS, discouraging further progress in its clinical trials. Nevertheless, the underlying mechanisms following M1 mAChR antagonism by clemastine may still be targeted using alternative antimuscarinic drugs. This review consolidates recent advancements in our understanding of the mechanisms by which antagonizing M1 mAChR promotes remyelination and summarizes alternative antimuscarinic drugs that could be leveraged to treat MS in the future. SIGNIFICANCE STATEMENT: Current treatments for multiple sclerosis are limited to disease management, and there is a need for restorative treatments that can reverse progressive forms of the disease. This review aims to summarize the potential mechanisms by which antagonizing the M1 muscarinic acetylcholine receptor could promote remyelination and elaborate on a collection of promising antimuscarinic drugs, consolidating the knowledge needed to target these mechanisms and develop therapeutics that could reverse the progress of demyelinating diseases like multiple sclerosis.

CC chemokine receptor (CCR) 5 promotes inflammatory responses by driving cell migration and scavenging chemokine. A CCR5 inhibitor Maraviroc has been approved for blocking HIV entry; however, inhibitors for the treatment of other diseases have had limited success, likely because of the complexity of CCR5 pharmacology and biology. CCR5 is activated by natural and engineered chemokines that elicit distinct signaling and trafficking responses, including receptor sequestration inside the cell. Intracellular sequestration may be therapeutically exploitable as a strategy for receptor inhibition, but the mechanisms by which different ligands promote receptor intracellular retention versus presence on the cell membrane are poorly understood. In this study, we systematically compared the time-dependent trafficking behavior of CCR5 following stimulation with its endogenous agonist, CCL5, and 2 CCL5 variants that promote CCR5 intracellular retention. Using a broad panel of pharmacologic assays, fluorescence microscopy, and live cell ascorbic acid peroxidase proximity labeling proteomics, we identified distinct ligand-dependent CCR5 trafficking patterns with temporal and spatial resolution. All 3 chemokines internalize CCR5 via β-arrestin-dependent, clathrin-mediated endocytosis but to different extents, with different kinetics and varying dependencies on G protein-coupled receptor kinase subtypes. The agonists differ in their ability to target the receptor to lysosomes for degradation, as well as to the Golgi compartment and the trans-Golgi network, and these trafficking patterns translate into distinct levels of ligand scavenging. The results provide insight into the cellular mechanisms behind CCR5 intracellular sequestration and suggest how trafficking can be exploited for the development of functional antagonists of CCR5. SIGNIFICANCE STATEMENT: CC chemokine receptor (CCR) 5 plays a crucial role in the immune system and is important in numerous physiological and pathological processes such as inflammation, cancer, and transmission of HIV. It responds to different ligands with distinct signaling and trafficking behaviors; notably, some ligands induce retention of the receptor inside the cell. This study reveals the cellular basis for receptor sequestration that can be exploited as a therapeutic strategy for inhibiting CCR5 function.

Nicotine App is a publicly accessible web-based simulator for the pharmacokinetics and pharmacodynamics of human smoking or vaping. The simulator exploits observations that nicotine has nearly equal concentrations in the plasma, cerebrospinal fluid, and endoplasmic reticulum, with time delays of just a few seconds. The simulations describe 2 nicotine-dependent processes. First, nicotine activates nicotinic acetylcholine receptor (nAChR) channels on the plasma membrane. Second, nicotine pharmacologically chaperones nAChRs, with an EC₅₀ much lower than that for channel activation. Beyond the scope of the stimulations, chaperoning leads to nAChR upregulation on the plasma membrane and to nicotine dependence. The simulated "Default Parameters" correspond to a moderate level of smoking: 14 cigarettes per day, 1 mg ingested per cigarette. The simulations explain how people who smoke and have slow nicotine metabolism consume fewer cigarettes per day, but they remain approximately as dependent on nicotine. With instructions from a user-supplied dose table, Nicotine App can also simulate an observed ad libitum pattern of smoking, variable puffing frequency, a transdermal nicotine patch, or other nicotine consumption. The simulations lead to the inference, from reports that nicotine dependence is minimal at nicotine levels <0.3 mg per cigarette, that these levels correspond to a chaperoned receptor fraction of 0.26. Nicotine App may be used for further research or for teaching about nicotine dependence. In the future, Nicotine App can also be used to support a wearable continuous nicotine monitor. SIGNIFICANCE STATEMENT: This study honors the memory of Bill Catterall by describing a web-based simulator of nicotine dependence. The simulator will find use along the spectrum ranging from public knowledge about nicotine dependence to further research on the topic.

Severe obesity is a complex chronic metabolic condition with a body mass index over 40 and can be caused, for example, by dysregulated G protein-coupled receptors (GPCRs) signaling. The orphan GPCR GPR61 had been linked to the regulation of metabolism and, here, we identify 34 mutations in the GPR61 gene which are present with much higher frequency in severe obesity samples from the UK10K obesity screen compared to the normal population. Furthermore, the cumulative sum of GPR61 mutations was found to be higher compared to the highly mutated and well-established target, melanocortin 4 receptor. Some GPR61 mutations presented an impact on ligand-independent GPR61-induced cAMP production. Specifically, R236C^5.66 compromised G_s protein activation and altered the pattern of cellular expression. Our data warrant further studies to assess the role of this orphan GPCR in metabolism in greater detail. SIGNIFICANCE STATEMENT: This study identified missense mutations, including previously unknown variants, of the GPR61 gene in severely obese patients. This occurrence was higher than for the well-established obesity target melanocortin 4 receptor. In the in vitro assays, 3 mutations of GPR61, in particular R236C^5.66, were loss of function because they reduced the constitutive activity of the receptor. The data support the notion that GPR61 can act as a promising target in obesity and its functions should be explored in future studies.

The Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII) mediates physiological long-term potentiation (LTP) of synaptic strength and pathological ischemic neuronal cell death. Both functions require CaMKII autophosphorylation at T286 (pT286) and binding to the NMDA-type glutamate receptor subunit GluN2B. The neuroprotection seen with 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) was thought to be mediated by impairing binding of the brain-specific CaMKIIα isozyme to GluN2B. However, we show that HOCPCA does not inhibit CaMKIIα enzymatic activity, pT286, cocondensation with GluN2B, or binding to GluN2B. Consistent with no effect on GluN2B binding in vitro or in HEK293 cells, HOCPCA also did not affect the CaMKIIα movement to excitatory synapses in hippocampal neurons in response to LTP stimuli. These findings leave the neuroprotective mechanism of HOCPCA unclear but explain why HOCPCA does not impair LTP. SIGNIFICANCE STATEMENT: This study found that the neuroprotective compound 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) does not directly interfere with Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII) activity or GluN2B binding. Although this leaves the neuroprotective mechanism of HOCPCA unclear, it explains why HOCPCA does not impair long-term potentiation. Overall, this limits the use of HOCPCA as a tool compound to study CaMKII functions, but not its clinical potential.