Journal of Pharmacology and Experimental Therapeutics最新文献

Interorgan crosstalk contributes to the pathogenesis of various disorders, and drug development based on interorgan crosstalk is attracting attention. The roles of nitric oxide (NO) derived from the NO synthases system (NOSs) in interorgan crosstalk remain unclear. We have investigated this issue by using our mice deficient in all 3 NOSs (triple n/i/eNOSs^-/- mice). We reported that 2/3 nephrectomized triple n/i/eNOSs^-/- mice die suddenly because of the early onset of myocardial infarction, suggesting the protective role of NO derived from NOSs in the crosstalk between the kidney and the heart. We studied the role of NO derived from NOSs expressed in the bone marrow in vascular lesion formation. Constrictive arterial remodeling and neointimal formation following unilateral carotid artery ligation were prominently aggravated in wild-type mice transplanted with triple n/i/eNOSs^-/- bone marrow cells as compared with those with wild-type bone marrow cells, suggesting the protective role of NO derived from NOSs in the crosstalk between the bone marrow and the blood vessel. We further investigated the role of NO derived from NOSs expressed in the bone marrow in pulmonary hypertension. The extent of pulmonary hypertension after chronic hypoxic exposure was markedly exacerbated in wild-type mice that underwent triple n/i/eNOSs^-/- bone marrow transplantation as compared with those that underwent wild-type bone marrow transplantation, suggesting the protective role of NO derived from NOSs in the crosstalk between the bone marrow and the lung. These lines of evidence demonstrate that systemic and myelocytic NOSs could be novel therapeutic targets for myocardial infarction, vascular disease, and pulmonary hypertension. SIGNIFICANCE STATEMENT: This study demonstrated partial nephrectomy accelerates the occurrence of myocardial infarction induced by systemic NOSs deficiency in triple n/i/eNOSs^-/- mice, that myelocytic NOSs deficiency aggravates vascular lesion formation after unilateral carotid artery ligation, and that myelocytic NOSs deficiency exacerbates chronic hypoxia-induced pulmonary hypertension. These results suggest that NO derived from NOSs plays a protective role in cardiovascular interorgan crosstalk, indicating that systemic and myelocytic NOSs could be important therapeutic targets for myocardial infarction, vascular disease, and pulmonary hypertension.

Chronic intestinal inflammation significantly contributes to the development of colorectal cancer and remains a pertinent clinical challenge, necessitating novel therapeutic approaches. Indole-based microbial metabolite mimics Felix Kopp Kortagere 6 (FKK6), which is a ligand and agonist of the pregnane X receptor (PXR), was recently demonstrated to have PXR-dependent anti-inflammatory and protective effects in a mouse model of dextran sodium sulfate (DSS)-induced acute colitis. Here, we examined the therapeutic potential of FKK6 in a mouse model (C57BL/6 FVB humanized PXR mice) of colitis-associated colon cancer (CAC) induced by azoxymethane and DSS. FKK6 (2 mg/kg) displayed substantial antitumor activity, as revealed by reduced size and number of colon tumors, improved colon histopathology, and decreased expression of tumor markers (c-MYC, β-catenin, Ki-67, and cyclin D) in the colon. In addition, we carried out a chronic toxicity (30 days) assessment of FKK6 (1 mg/kg and 2 mg/kg) in C57BL/6 mice. Histological examination of tissues, biochemical blood analyses, and immunohistochemical staining for Ki-67 and γ-H2AX showed no difference between FKK6-treated and control mice. Comparative metabolomic analyses in mice exposed for 5 days to DSS and administered with FKK6 (0.4 mg/kg) revealed no significant effects on several classes of metabolites in the mouse fecal metabolome. Ames and micronucleus tests showed no genotoxic and mutagenic potential of FKK6 in vitro. In conclusion, anticancer effects of FKK6 in azoxymethane/DSS-induced CAC, together with FKK6 safety data from in vitro tests and in vivo chronic toxicity study, and comparative metabolomic study, are supportive of the potential therapeutic use of FKK6 in the treatment of CAC. SIGNIFICANCE STATEMENT: Microbial metabolite mimicry proposes that chemical mimics of microbial metabolites that serve to protect hosts against aberrant inflammation in the gut could serve as a new paradigm for the development of drugs targeting inflammatory bowel disease if, like the parent metabolite, is devoid of toxicity but more potent against the microbial metabolite receptor. We identified a chemical mimic of Felix Kopp Kortagere 6, and we propose that Felix Kopp Kortagere 6 is devoid of toxicity yet significantly reduces tumor formation in an azoxymethane-dextran sodium sulfate model of murine colitis-induced colon cancer.

With the current pressure to reduce opioid usage in the clinical setting, there is a call for the development of adjunct therapies. Although opioids remain the primary analgesic used in the treatment of moderate to severe pain, these drugs come with negative side effects, such as increased potential for abuse. The overlap in expression of opioid and GABA receptors suggests that the 2 systems may interact. Therefore, to investigate this interaction, our study used the GABA_B receptor agonist, baclofen, because it has previously been used as a treatment for spasticity and addiction and has demonstrated weak analgesic properties. Our study focused on the interaction between baclofen and opioid analgesics regarding analgesic efficacy and abuse potential. Analgesia was assessed through hot plate testing and reward was assessed through conditioned place preference testing in outbred CD1 mice. These interactions were examined with morphine, methadone, oxycodone, and fentanyl using isobolographic analyses. All opioids tested with baclofen demonstrate synergism in analgesia and no consistent significant interactions in place preference conditioning. Together these data support the use of baclofen coupled with opioids to enhance the analgesia, with no concomitant increase in abuse liability and associated common side effects of opioid drugs. SIGNIFICANCE STATEMENT: The combination of the commonly prescribed drug, baclofen, and a variety of opioids exhibits a synergistic analgesic effect allowing for lower doses of opioids to be used for equivalent analgesic effect. Synergistic analgesia was seen without concomitant enhanced tolerance, constipation, or reward, and across species, suggesting a beneficial interaction for pain relief.

Cisplatin causes permanent hearing loss or cisplatin-induced ototoxicity in over 50% of treated patients with cancer, leading to significant social and functional limitations. Interindividual variability in developing hearing loss suggests the role of genetic predispositions to cisplatin-induced hearing loss. We investigated genetic associations between cisplatin-induced ototoxicity and toll-like receptor 4 (TLR4), an immune receptor known to mediate inflammatory responses to cisplatin. Using a case-control candidate gene approach, we identified 20 single nucleotide polymorphisms at the TLR4 locus with significant protection against ototoxicity in a cohort of 213 adult patients, followed by an independent pediatric patient cohort (n = 357). Combined cohort analysis demonstrated a significant association between cisplatin-induced ototoxicity protection and a single variant in the TLR4 promoter, rs10759932. We showed that rs10759932 downregulated TLR4 expression that is normally induced by cisplatin. This work provides pharmacogenetic and functional evidence to implicate TLR4 with cisplatin-induced hearing loss in patients. SIGNIFICANCE STATEMENT: Adult and pediatric patients carrying toll-like receptor 4 (TLR4) genetic variants were protected against developing cisplatin-induced hearing loss following cisplatin treatment. Important variants in the TLR4 promoter disrupted a drug-gene interaction between cisplatin and TLR4, mirroring the protective effect conferred by genetic inhibition of TLR4. These variants have the potential to improve the prediction of cisplatin toxicity, allowing for more precise chemotherapy treatment.

Fatty acid amide hydrolase (FAAH) serves as the primary enzyme responsible for degrading the endocannabinoid anandamide. Inhibition of FAAH, either through pharmacological means or genetic manipulation, can effectively reduce inflammation in various organs, including the brain, colon, heart, and kidneys. Infusion of a FAAH inhibitor into the kidney medulla induces diuretic and natriuretic effects. Moreover, FAAH knockout mice show protection against both post renal ischemia/reperfusion injury and cisplatin-induced acute kidney injury (AKI), although through distinct mechanisms. This study tested the hypothesis that pharmacological inhibition of FAAH activity mitigates cisplatin-induced AKI, thus, exploring potential renoprotective mechanism. Male wild-type C57BL/6J were administered an oral gavage of a FAAH inhibitor (PF-04457845, 5 mg/kg) or vehicle (10% PEG200+5% Tween 80+normal saline) at 72, 48, 24, and 2 hours before and 24 and 48 hours after a single intraperitoneal injection of cisplatin (25 mg/kg). Mice were euthanized 72 hours after cisplatin treatment. Compared with vehicle-treated mice, PF-04457845-treated mice showed a decrease of cisplatin-induced plasma creatinine, blood urea nitrogen levels, kidney injury biomarkers (neutrophil gelatinase-associated lipocalin and kidney injury molecule-1) and renal tubular damage. The renal protection from oral gavage of PF-04457845 against cisplatin-induced nephrotoxicity was associated with an enhanced endocannabinoid anandamide tone and reduced levels of DNA damage response biomarkers p53 and p21. Our work demonstrated that PF-04457845 effectively alleviates cisplatin-induced nephrotoxicity in mice, underscoring the potential of oral administration of a FAAH inhibitor as a novel strategy to prevent cisplatin nephrotoxicity. SIGNIFICANCE STATEMENT: Oral administration of the fatty acid amide hydrolase (FAAH) inhibitor, PF-04457845, reduced cisplatin-induced DNA damage response, tubular damage, and kidney dysfunction. Inhibition of FAAH represents a promising approach to prevent cisplatin-induced nephrotoxicity.

Copper (Cu) is an essential cofactor for metalloenzymes such as cytochrome c oxidase (CcO), the terminal enzyme of the mitochondrial electron transport chain. Mutations that directly or indirectly prevent Cu transport to mitochondria result in lethal pediatric diseases, such as Menkes disease. There is no clinically approved treatment for Menkes disease. We recently discovered that an investigational chemotherapy drug, elesclomol (ES), when complexed with Cu (ES-Cu), rescues mitochondrial Cu deficiency, activates CcO, and prevents perinatal lethality in a mouse model of Menkes disease. However, ES-Cu also has the potential to trigger cuproptosis, a type of Cu-dependent cell death. Therefore, to develop ES-Cu as a therapeutic agent for Menkes disease, it is critical to determine the therapeutic index of ES-Cu in Cu-deficient models. To this end, we used a Cu-deficient rat cardiomyocyte cell line and a mottled-brindled mouse model of severe Menkes disease to determine the toxicity and efficacy of ES-Cu. Our cell culture studies demonstrated that the EC₅₀ of ES-Cu is ∼50-fold lower than IC₅₀. Moreover, the biomarkers of Cu toxicity, including lipoylated proteins and a subset of iron-sulfur cluster-containing proteins of mitochondria, are activated only when ES-Cu is used at ∼10-fold to 25-fold higher than its EC₅₀. Importantly, none of these biomarkers are activated in mottled-brindled mice treated with therapeutic doses of ES-Cu. Our study shows that ES-Cu can deliver Cu to CcO both in vitro and in vivo without triggering cuproptosis, a finding that could facilitate its use in Cu deficiency disorders, such as Menkes disease. SIGNIFICANCE STATEMENT: Genetic copper (Cu) deficiency causes lethal pediatric diseases, such as Menkes disease, which lacks approved treatment. Recently, the therapeutic potential of elesclomol (ES), a Cu-transporting chemotherapeutic drug, in a mouse model of Menkes disease has been reported. Because of the potential risk of Cu-induced toxicity from ES-Cu, it is crucial to determine its therapeutic index. Here, the biomarkers of ES-Cu efficacy and toxicity in Cu-deficient disease models were measured to demonstrate that ES-Cu can restore cuproenzymes without triggering toxicity biomarkers.

Heart failure is rapidly increasing and is a growing burden on human health and the economy in the world. The functional role of mRNA regulation in the pathogenesis of heart failure remains to be elucidated. Carbon catabolite repression 4-negative on TATA-less complex is a multisubunit protein complex that deadenylates mRNA, a process of exonuclease-mediated degradation of mRNA poly(A) tail. Here we show the cardiac protective roles of deadenylase subunit CNOT6L against cardiac stress. After 2 weeks of transverse aortic constriction (TAC)-induced pressure overload, expression of CNOT6L deadenylase subunit was significantly upregulated in the mouse hearts. When CNOT6L gene was genetically deleted, the mice exhibited marked decline of left ventricular contractility and enhancement of fibrosis at 2 weeks after TAC. Transcriptome analyses elucidated that CNOT6L targets tenascin-C mRNA, which stimulates tissue fibrosis and inflammation. CNOT6L deletion markedly upregulated tenascin-C expression in cardiac fibroblasts. Poly(A) tail length and luciferase reporter analyses revealed that CNOT6L catalyzes deadenylation of tenascin-C mRNA likely through interaction with the cis-element in its 3'-untranslated region. Double knockout of tenascin-C and CNOT6L ameliorated cardiac fibrosis and dysfunction in single CNOT6 knockout mice under TAC or chronic infusion of angiotensin II. Thus, CNOT6L deadenylase prevents the progression of heart failure through downregulation of the expression of tenascin-C in cardiac fibroblasts, implicating a potential therapeutic strategy of targeting mRNA deadenylation. SIGNIFICANCE STATEMENT: To our knowledge, this study provides the first evidence that posttranscriptional regulation of tenascin-C expression in cardiac fibroblasts, including cell-type-specific roles of CNOT6L-mediated mRNA deadenylation, is crucial to maintain heart functions against pressure overload stress or angiotensin II-induced hypertension, implicating a potential therapeutic strategy of targeting mRNA deadenylation.