Cannabinoid-2 receptor limits inflammation, oxidative/nitrosative stress, and cell death in nephropathy

Δ9-tetrahydrocannabinol induces blood-brain barrier disruption: Involving the activation of CB1R and oxidative stress

Cannabis abuse has increased with the continuous relaxation of cannabis policies. However, the mechanism by which Δ9-tetrahydrocannabinol (THC) negatively affects the central nervous system, especially the blood-brain barrier (BBB), remains unclear. THC exposure models were established in vivo and in vitro. The BBB properties were examined using Western blotting (WB), immunofluorescence staining (IF), transendothelial electrical resistance (TEER), and flux of sodium fluorescein (SF). The oxidative stress regulators were examined using IF and assay kits. The activation of cannabinoid receptor 1 (CB1R) was examined using WB and IF. The THC exposure caused barrier integrity damage and endothelial dysfunction in murine and hCMEC/D3 cells, conclude albumin leakage, increased SF permeability and reduced TEER value. The expression of tight junction proteins, including claudin 5, occludin, and junctional adhesion molecules, was decreased. Additionally, key oxidative stress regulators, including reactive oxygen species, hydrogen peroxide, malonaldehyde levels, and antioxidant enzyme activities, including catalase, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase, and heme oxygenase 1, were increased. Activation of CB1R has been detected in brain microvascular endothelial cells in vivo and in vitro. Furthermore, inhibition of oxidative stress and CB1R could mitigate the aforementioned conditions and BBB damage after THC exposure. The effect of THC on murine and human brain microvascular endothelial cells revealed that THC-induced BBB damage was partly mediated by CB1R activation, triggering the oxidative stress response. This study provides new theoretical insights into the mechanisms of THC-induced BBB damage and offers novel scientific evidence for the potential neurotoxicity and adverse reactions induced by THC.

The Role of Endocannabinoids in Physiological Processes and Disease Pathology: A Comprehensive Review

The endocannabinoid system is a complex communication system involved in maintaining homeostasis in various physiological processes, including metabolism, immune response, pain modulation, and neuroprotection. Endocannabinoids, mainly anandamide and 2-arachidonoylglycerol, are natural ligands of the cannabinoid receptors CB1 and CB2, which are widely distributed throughout the central nervous system and peripheral tissues. Their biosynthesis, degradation, and interaction with other signaling pathways play crucial roles in both health and disease. This article provides a comprehensive overview of the physiological and pathological roles of endocannabinoids, discusses their potential as therapeutic targets, and highlights recent advances in endocannabinoid-based treatments.

Effect of cannabinoids on the efficacy and side effects of anticancer therapeutic strategies - Current status of preclinical and clinical research

Cannabinoids have attracted increasing attention in cancer research in recent decades. A major focus of current preclinical and clinical studies is on the interactions and potential risks when combined with chemotherapeutic agents, targeted therapies and other anticancer strategies. Given the extensive preclinical data on additive, synergistic and, in some cases, antagonistic tumor cell killing effects of chemotherapeutic agents and cannabinoids when co-administered, a critical analysis of these data seems essential. The available data mainly relate to combination treatments for glioblastoma, hematological malignancies and breast cancer, but also for other cancer types. Such an analysis also appears necessary because cannabinoids are used as an option to treat nausea and vomiting caused by chemotherapy, as well as tumor-related pain, and cancer patients sometimes take cannabinoids without a medical prescription. In addition, numerous recent preclinical studies also suggest cannabinoid-mediated relief of other chemotherapy-related side effects such as peripheral neuropathy, nephrotoxicity, cardiotoxicity, cystitis, bladder complications and mucositis. To summarize, the data available to date raise the prospect that cannabinoids may increase the efficacy of chemotherapeutic agents while reducing their side effects. However, preclinical studies on anticancer interactions are mostly limited to cytotoxicity analyses. An equally thorough investigation of the effects of such combinations on the immune system and on the tumorigenic levels of angiogenesis, invasion and metastasis is still pending. On this basis, a comprehensive understanding for the evaluation of a targeted additional treatment of various cancers with cannabinoids could be established.

Cannabinoid-2 Receptor Activation Attenuates Sulfur Mustard Analog 2-Chloroethyl-Ethyl-Sulfide-Induced Acute Lung Injury in Mice

Background: Exposure to sulfur mustard (SM; 2,2'-dichlorodiethyl sulfide) causes toxicity in the human body, particularly the lungs. The molecular mechanisms of SM-induced lung damage are elusive, and no effective treatments exist. This study explores the anti-inflammatory potential of cannabinoid receptor 2 (CB2R) activation in mitigating acute lung injury (ALI) and inflammation induced by 2-chloroethyl ethyl sulfide (CEES), a structural analog of SM. Methods: C57BL/6J mice were exposed to CEES via intratracheal administration to model ALI. CB2R activation was achieved through the intraperitoneal administration of HU308, a selective synthetic agonist. ALI and inflammation were evaluated at 48 h post-exposure to CEES. Bronchoalveolar lavage fluid (BALF) was collected to measure total cells, protein, and cytokines. Lung injury, inflammatory signaling in alveolar macrophages (AMs), and matrix metalloproteinase-9 (MMP-9) activity were assessed via histological analysis, immunoblotting, and gelatin zymography, respectively. Results: CEES exposure led to an increase in immune cell infiltration, pro-inflammatory cytokines (IL-6 and TNF-α), and pro-MMP9 levels in the BALF, which were significantly decreased by HU308 treatment. The activation of CB2R attenuated CEES-induced NF-κB activation and reduced pro-inflammatory M1 markers (iNOS, and Cox-2) but did not alter the increase in the M2 marker arginase-1. CB2R activation mitigated CEES-induced oxidative stress, as evidenced by lower levels of heme oxygenase-1 (HO-1) and reactive oxygen species (ROS) in mouse AMs. Additionally, 4-hydroxynonenal (4-HNE) levels were reduced in the lungs of HU308-treated mice but were elevated after CEES exposure. Conclusions: These findings suggest that CB2R activation alleviates CEES-induced ALI and inflammation in mice, supporting its potential as a therapeutic approach for vesicant-induced pulmonary injury.

Mitigation of cisplatin-induced acute kidney injury through oral administration of fatty acid amide hydrolase inhibitor PF-04457845

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.

Chemical Probes for Investigating the Endocannabinoid System

Cannabis sativa has been used therapeutically since early civilizations, with key cannabinoids Δ9-tetrahydrocannabinol (THC) 3.1 and cannabidiol characterized in the 1960s, leading to the discovery of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R) and the endocannabinoid system (ECS) in the 1990s. The ECS, involving endogenous ligands like 2-arachidonoylglycerol (2-AG) 1.1, anandamide (N-arachidonoylethanolamine (AEA)) 1.2, and various proteins, regulates vital processes such as sleep, appetite, and memory, and holds significant therapeutic potential, especially for neurological disorders. Small molecule-derived pharmacological tools, or chemical probes, target key components of the ECS and are crucial for target validation, mechanistic studies, pathway elucidation, phenotypic screening, and drug discovery. These probes selectively interact with specific proteins or pathways, enabling researchers to modulate target activity and observe biological effects. When they carry an additional reporter group, they are referred to as labeled chemical probes. Developed through medicinal chemistry, structural biology, and high-throughput screening, effective chemical probes must be selective, potent, and depending on their purpose meet additional criteria such as cell permeability and metabolic stability.This chapter describes high-quality labeled and unlabeled chemical probes targeting ECS constituents that have been successfully applied for various research purposes. CB1R and CB2R, class A G protein-coupled receptors, are activated by 2-AG 1.1, AEA 1.2, and THC 3.1, with numerous ligands developed for these receptors. Imaging techniques like single-photon emission computed tomography, positron emission tomography, and fluorescently labeled CB1R and CB2R probes have enhanced CB receptor studies. CB2R activation generally results in immunosuppressive effects, limiting tissue injury. AEA 1.2 is mainly degraded by fatty acid amide hydrolase (FAAH) or N-acylethanolamine acid amidase (NAAA) into ethanolamine and arachidonic acid (AA) 1.3. FAAH inhibitors increase endogenous fatty acid amides, providing analgesic effects without adverse effects. NAAA inhibitors reduce inflammation and pain in animal models. Diacylglycerol lipase (DAGL) is essential for 2-AG 1.1 biosynthesis, while monoacylglycerol lipase (MAGL) degrades 2-AG 1.1 into AA 1.3, thus regulating cannabinoid signaling. Multiple inhibitors targeting FAAH and MAGL have been generated, though NAAA and DAGL probe development lags behind. Similarly, advancements in inhibitors targeting endocannabinoid (eCB) cellular uptake or trafficking proteins like fatty acid-binding proteins have been slower. The endocannabinoidome (eCBome) includes the ECS and related molecules and receptors, offering therapeutic opportunities from non-THC cannabinoids and eCBome mediators. Ongoing research aims to refine chemical tools for ECS and eCBome study, addressing unmet medical needs in central nervous system disorders and beyond.

In vivo assessment of the nephrotoxic effects of the synthetic cannabinoid AB-FUBINACA

BACKGROUND

The widespread misuse of synthetic cannabinoids (SCs) has led to a notable increase in reported adverse effects, raising significant health concerns. SCs use has been particularly associated with acute kidney injury (AKI). However, the pathogenesis of SCs-induced AKI is not well-understood.

METHODS

We investigated the nephrotoxic effect of acute administration of N-[(1S)- 1-(aminocarbonyl)-2-methylpropyl]-1-[(4-fluorophenyl)methyl]-1H-indazole-3-carboxamide (AB-FUBINKA) (3 mg/kg for 5 days) in mice. Various parameters of oxidative stress, inflammation, and apoptosis have been quantified. The expressions of mitochondrial complexes (I-V) in renal tissues were also assessed.

RESULTS

Our findings showed that AB-FUBINACA induced substantial impairment in the renal function that is accompanied by elevated expression of renal tubular damage markers; KIM-1 and NGAL. Administration of AB-FUBINACA was found to be associated with a significant increase in the expression of oxidative stress markers (iNOS, NOX4, NOX2, NOS3) and the level of lipid peroxidation in the kidney. The expression of pro-inflammatory markers (IL-6, TNF-alpha, NF-kB) was also enhanced following exposure to AB-FUBINACA. These findings were also correlated with increased expression of major apoptosis regulatory markers (Bax, caspase-9, caspase-3) and reduced expression of mitochondrial complexes I, III, and IV.

CONCLUSION

These results indicate that AB-FUBINACA can trigger oxidative stress and inflammation, and activate caspase-dependent apoptosis in the kidney, with these processes being possibly linked to disruption of mitochondrial complexes and could be an underlying mechanism of SCs-induced nephrotoxicity.

Role of G protein coupled receptors in acute kidney injury

Acute kidney injury (AKI) is a clinical condition characterized by a rapid decline in kidney function, which is associated with local inflammation and programmed cell death in the kidney. The G protein-coupled receptors (GPCRs) represent the largest family of signaling transduction proteins in the body, and approximately 40% of drugs on the market target GPCRs. The expressions of various GPCRs, prostaglandin receptors and purinergic receptors, to name a few, are significantly altered in AKI models. And the role of GPCRs in AKI is catching the eyes of researchers due to their distinctive biological functions, such as regulation of hemodynamics, metabolic reprogramming, and inflammation. Therefore, in this review, we aim to discuss the role of GPCRs in the pathogenesis of AKI and summarize the relevant clinical trials involving GPCRs to assess the potential of GPCRs and their ligands as therapeutic targets in AKI and the transition to AKI-CKD.

Cannabinoid Receptor-2 agonist AM1241 Attenuates Myocardial Ischemia-Reperfusion-Induced Oxidative Stress in Rats via Nrf2/HO-1 Pathway

OBJECTIVE

The cannabinoid receptor-2 agonist AM1241 exhibits notable cardioprotective effects against myocardial infarction, positioning it as a promising therapeutic candidate for cardiovascular disease. This study explores AM1241's protective role in myocardial ischemia-reperfusion (IR) injury and its association with the Nrf2/HO-1 pathway.

METHODS

In an established Sprague-Dawley rat IR model, AM1241's impact on cardiac injury was assessed through echocardiography, 2,3,5-triphenyl tetrazolium chloride staining, and histological analysis. H9c2 cells underwent hypoxia-reoxygenation, with AM1241's influence on cell viability determined by the CCK-8 assay. Reactive oxygen species (ROS) production was measured using the DCFH-DA assay, and Nrf2 and HO-1 protein expressions were evaluated through immunofluorescence and Western blot.

RESULTS

Myocardial ischemia-reperfusion injury (MIRI) increased infarct size, inflammatory cell presence, oxidative and nitrosative stress, impaired cardiac function, and elevated apoptosis rates. AM1241 mitigated these effects, enhancing cell viability, reducing ROS production, and upregulating Nrf2 and HO-1 expression. The antioxidant effect of AM1241 was inhibited by ML385 intervention.

CONCLUSIONS

AM1241 attenuates oxidative stress, alleviates MIRI, and activates the Nrf2/HO-1 signaling pathway, underscoring its potential as a therapeutic strategy for MIRI.

A Highly Potent, Orally Bioavailable Pyrazole-Derived Cannabinoid CB2 Receptor- Selective Full Agonist for In Vivo Studies

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein-mediated efflux from the brain. 3H and 14C labeled RNB-61 showed apparent K d values of <4 nM toward human CB2R in both cell and tissue experiments. The 6,800-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.

Patent review of cannabinoid receptor type 2 (CB2R) modulators (2016-present)

INTRODUCTION

Cannabinoid receptor type 2 (CB2R), predominantly expressed in immune tissues, is believed to play a crucial role within the body's protective mechanisms. Its modulation holds immense therapeutic promise for addressing a wide spectrum of dysbiotic conditions, including cardiovascular, gastrointestinal, liver, kidney, neurodegenerative, psychiatric, bone, skin, and autoimmune diseases, as well as lung disorders, cancer, and pain management.

AREAS COVERED

This review is an account of patents from 2016 up to 2023 which describes novel CB2R ligands, therapeutic applications, synthesis, as well as formulations of CB2R modulators.

EXPERT OPINION

The patents cover a vast, structurally diverse chemical space. The focus of CB2R ligand development has shifted from unselective dual-cannabinoid receptor type 1 (CB1R) and 2 agonists toward agonists with high selectivity over CB1R, particularly for indications associated with inflammation and tissue injury. Currently, there are at least eight CB2R agonists and one antagonist in active clinical development. A better understanding of the endocannabinoid system (ECS) and in particular of CB2R pharmacology is required to unlock the receptor's full therapeutic potential.

Exploring the Possible Role of Cannabinoids in Managing Post-cardiac Surgery Complications: A Narrative Review of Preclinical Evidence and a Call for Future Research Directions

ABSTRACT

Open-heart surgery with cardiopulmonary bypass often leads to complications including pain, systemic inflammation, and organ damage. Traditionally managed with opioids, these pain relief methods bring potential long-term risks, prompting the exploration of alternative treatments. The legalization of cannabis in various regions has reignited interest in cannabinoids, such as cannabidiol, known for their anti-inflammatory, analgesic, and neuroprotective properties. Historical and ongoing research acknowledges the endocannabinoid system's crucial role in managing physiological processes, suggesting that cannabinoids could offer therapeutic benefits in postsurgical recovery. Specifically, cannabidiol has shown promise in managing pain, moderating immune responses, and mitigating ischemia/reperfusion injury, underscoring its potential in postoperative care. However, the translation of these findings into clinical practice faces challenges, highlighting the need for extensive research to establish effective, safe cannabinoid-based therapies for patients undergoing open-heart surgery. This narrative review advocates for a balanced approach, considering both the therapeutic potential of cannabinoids and the complexities of their integration into clinical settings.

A highly potent, orally bioavailable pyrazole-derived cannabinoid CB2 receptor-selective full agonist for in vivo studies

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein mediated efflux from the brain. 3H and 14C labelled RNB-61 showed apparent K d values < 4 nM towards human CB2R in both cell and tissue experiments. The >6000-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.

Cell Death in Acute Organ Injury and Fibrosis

Tissue fibrosis is characterized by the excessive accumulation of extracellular matrix in various organs, including the lungs, liver, skin, kidneys, pancreas, and heart, ultimately leading to organ failure [...].

A Retrospective Cohort Study That Examined the Impact of Cannabis Consumption on Long-Term Kidney Outcomes

Background: Cannabis consumption for recreational and medical use is increasing worldwide. However, the long-term effects on kidney health and disease are largely unknown. Materials and Methods: Post hoc analysis of cannabis use as a risk factor for kidney disease was performed using data from the Assessment, Serial Evaluation, and Subsequent Sequelae of Acute Kidney Injury (ASSESS-AKI) study that enrolled hospitalized adults with and without acute kidney injury from four U.S. centers during 2009-2015. Associations between self-reported cannabis consumption and the categorical and continuous outcomes were determined using multivariable Cox regression and linear mixed models, respectively. Results: Over a mean follow-up of 4.5±1.8 years, 94 participants without chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR] >60 mL/min/1.73 m2) who consumed cannabis had similar rates of annual eGFR decline versus 889 nonconsumers (mean difference=-0.02 mL/min/1.73 m2/year, p=0.9) and incident CKD (≥25% reduction in eGFR compared with the 3-month post-hospitalization measured eGFR and achieving CKD stage 3 or higher) (adjusted hazard ratio [aHR]=1.2; 95% confidence interval [CI]=0.7-2.0). Nineteen participants with CKD (eGFR <60 mL/min/1.73 m2) who consumed cannabis had more rapid eGFR decline versus 597 nonconsumers (mean difference=-1.3 mL/min/1.73 m2/year; p=0.02) that was not independently associated with an increased risk of CKD progression (≥50% reduction in eGFR compared with the 3-month post-hospitalization eGFR, reaching CKD stage 5, or receiving kidney replacement therapy) (aHR=1.6; 95% CI=0.7-3.5). Cannabis consumption was not associated with the rate of change in urine albumin to creatinine ratio (UACR) over time among those with (p=0.7) or without CKD (p=0.4). Conclusions: Cannabis consumption did not adversely affect the kidney function of participants without CKD but was associated with a faster annual eGFR decline among participants with CKD. Cannabis consumption was not associated with changes in UACR over time, incident CKD, or progressive CKD regardless of baseline kidney function. Additional research is needed to investigate the kidney endocannabinoid system and the impact of cannabis use on kidney disease outcomes.

The intervention of cannabinoid receptor in chronic and acute kidney disease animal models: a systematic review and meta-analysis

AIM

Cannabinoid receptors are components of the endocannabinoid system that affect various physiological functions. We aim to investigate the effect of cannabinoid receptor modulation on kidney disease.

METHODS

PubMed, Web of Science databases, and EMBASE were searched. Articles selection, data extraction and quality assessment were independently performed by two investigators. The SYRCLE's RoB tool was used to assess the risk of study bias, and pooled SMD using a random-effect model and 95% CIs were calculated. Subgroup analyses were conducted in preselected subgroups, and publication bias was evaluated. We compared the effects of CB1 and CB2 antagonists and/or knockout and agonists and/or genetic regulation on renal function, blood glucose levels, body weight, and pathological damage-related indicators in different models of chronic and acute kidney injury.

RESULTS

The blockade or knockout of CB1 could significantly reduce blood urea nitrogen [SMD,- 1.67 (95% CI - 2.27 to - 1.07)], serum creatinine [SMD, - 1.88 (95% CI - 2.91 to - 0.85)], and albuminuria [SMD, - 1.60 (95% CI - 2.16 to - 1.04)] in renal dysfunction animals compared with the control group. The activation of CB2 group could significantly reduce serum creatinine [SMD, - 0.97 (95% CI - 1.83 to - 0.11)] and albuminuria [SMD, - 2.43 (95% CI - 4.63 to - 0.23)] in renal dysfunction animals compared with the control group.

CONCLUSIONS

The results suggest that targeting cannabinoid receptors, particularly CB1 antagonists and CB2 agonists, can improve kidney function and reduce inflammatory responses, exerting a renal protective effect and maintaining therapeutic potential in various types of kidney disease.

Artesunate-Nanoliposome-TPP, a Novel Drug Delivery System That Targets the Mitochondria, Attenuates Cisplatin-Induced Acute Kidney Injury by Suppressing Oxidative Stress and Inflammatory Effects

Background

Acute kidney injury (AKI) is a syndrome, posing a substantial healthcare burden. The pathological basis of AKI is associated with inflammation and oxidative stress which cause additional damage to mitochondria. Artesunate (ATS) is a derivative of artemisinin isolated from Artemisia annua L. that is an effective treatment for malaria and favored for the prevention and treatment of kidney diseases. However, there are still challenges related to its efficacy, including poor water solubility, limited oral bioavailability and short half-life. Liposome-based nanoparticles are used for drug delivery due to their ideal biocompatibility and their ability to improve the bioavailability of specific drugs and enhance drug efficacy.

Methods

In this study, a novel TPP-based natural ATS-nanoliposome, namely T-A-Ls, was applied for the treatment of AKI. ATS was encapsulated with or without triphenylphosphonium (TPP)-modified nanoliposomes. AKI was induced by cisplatin in C57BL/6J mice and a cisplatin-induced injury model was generated in HK-2 cells in vitro. Blood urea nitrogen (BUN), serum creatinine (Scr) measurements and section staining were utilized to assess renal protective effect of T-A-Ls. Inflammatory-related factors and proteins were quantified via Elisa, Immunofluorescence and Western Blot (WB). The anti-mitochondrial oxidative stress effect of T-A-Ls was determined by ROS, JC-1 and oxygen consumption rate (OCR) kits. Immunohistochemistry and WB were conducted to measure associated protein expressions. In vivo biodistribution and the concentration of T-A-Ls in kidney were also explored.

Results

T-A-Ls exhibited good oxidative resistance, preferential renal uptake, mitochondrial targeting, and it ameliorated kidney injury in cisplatin-induced AKI mice. Mitochondrial dysfunction, ATP production and respiratory capacity were improved in damaged HK-2 cells; ROS content decreased while mitochondrial membrane potential recovered. T-A-Ls exerted renal protection by inhibiting inflammation and reducing oxidative stress; these effects were mediated by a downregulation in the expression of RAGE and iNOS and an upregulation in both Nrf2 and HO-1.

Conclusion

T-A-Ls could improve the delivery of ATS to the kidney, offering a promising avenue to treat AKI.

CB2 Cannabinoid Receptor as a Potential Target in Myocardial Infarction: Exploration of Molecular Pathogenesis and Therapeutic Strategies

The lipid endocannabinoid system has recently emerged as a novel therapeutic target for several inflammatory and tissue-damaging diseases, including those affecting the cardiovascular system. The primary targets of cannabinoids are cannabinoid type 1 (CB1) and 2 (CB2) receptors. The CB2 receptor is expressed in the cardiomyocytes. While the pathological changes in the myocardium upregulate the CB2 receptor, genetic deletion of the receptor aggravates the changes. The CB2 receptor plays a crucial role in attenuating the advancement of myocardial infarction (MI)-associated pathological changes in the myocardium. Activation of CB2 receptors exerts cardioprotection in MI via numerous molecular pathways. For instance, delta-9-tetrahydrocannabinol attenuated the progression of MI via modulation of the CB2 receptor-dependent anti-inflammatory mechanisms, including suppression of pro-inflammatory cytokines like IL-6, TNF-α, and IL-1β. Through similar mechanisms, natural and synthetic CB2 receptor ligands repair myocardial tissue damage. This review aims to offer an in-depth discussion on the ameliorative potential of CB2 receptors in myocardial injuries induced by a variety of pathogenic mechanisms. Further, the modulation of autophagy, TGF-β/Smad3 signaling, MPTP opening, and ROS production are discussed. The molecular correlation of CB2 receptors with cardiac injury markers, such as troponin I, LDH1, and CK-MB, is explored. Special attention has been paid to novel insights into the potential therapeutic implications of CB2 receptor activation in MI.

Aerobic exercise training reduces deep-frying oil-induced apoptosis of hippocampal tissue by reducing oxidative stress in male rats

Deep-frying oil (DFO) contains high amounts of free radicals, and consuming foods prepared with this method causes damage to nervous tissue due to oxidative stress (OS). Since moderate-intensity aerobic exercise training (AT) reduces OS, the current search investigated the effects of AT on OS, apoptosis, and neurogenesis markers in the hippocampal tissue of DFO-fed rats. Eighteen Wistar male rats (200-280 gr) were randomly allocated to a control group fed with normal food (Con-ND), a control group receiving DFO (Con-DFO), and a group receiving DFO-aerobic exercise (EX-DFO) (n = 6 in each). DFO was gavaged for four weeks, five days a week, with a dose of 2 ml. AT included running on a treadmill for four weeks and five sessions per week (40 min per session). The expression of genes B-cell lymphoma 2 (BCL-2), Protein X associated with Bcl-2 (BAX), Caspase-3 (Casp-3), and Caspase-9 (Casp-9) was measured by PCR method. The ELISA method was used to calculate levels of Superoxide dismutase (SOD) and Catalase (CAT) activity, malondialdehyde (MDA), and Brain-Derived Neurotrophic Factor (BDNF). Also, the expression of the proteins Cannabinoid receptor type 1(CB1), Cannabinoid receptor type2 (CB2), Glial fibrillary acidic protein (GFAP), Neuronal nuclei (NeuN), and DNA fragmentation was evaluated by Immunohistochemical and TUNEL staining. DFO feeding led to a significant increase in apoptotic markers, such as BAX, Casp-3, and Casp-9 gene expression, and DNA fragmentation (p ≤ 0.05) while decreasing BDNF concentration SOD activity (p ≤ 0.05). AT significantly reduced the BAX, Casp-3, Casp-9, MDA, CB1, GFAP, and DNA fragmentation (p ≤ 0.05). In conclusion, AT can reduce the harmful effects of feeding with DFO on the hippocampal tissue.

Goods and Bads of the Endocannabinoid System as a Therapeutic Target: Lessons Learned after 30 Years

The cannabis derivative marijuana is the most widely used recreational drug in the Western world and is consumed by an estimated 83 million individuals (∼3% of the world population). In recent years, there has been a marked transformation in society regarding the risk perception of cannabis, driven by its legalization and medical use in many states in the United States and worldwide. Compelling research evidence and the Food and Drug Administration cannabis-derived cannabidiol approval for severe childhood epilepsy have confirmed the large therapeutic potential of cannabidiol itself, Δ9-tetrahydrocannabinol and other plant-derived cannabinoids (phytocannabinoids). Of note, our body has a complex endocannabinoid system (ECS)-made of receptors, metabolic enzymes, and transporters-that is also regulated by phytocannabinoids. The first endocannabinoid to be discovered 30 years ago was anandamide (N-arachidonoyl-ethanolamine); since then, distinct elements of the ECS have been the target of drug design programs aimed at curing (or at least slowing down) a number of human diseases, both in the central nervous system and at the periphery. Here a critical review of our knowledge of the goods and bads of the ECS as a therapeutic target is presented to define the benefits of ECS-active phytocannabinoids and ECS-oriented synthetic drugs for human health. SIGNIFICANCE STATEMENT: The endocannabinoid system plays important roles virtually everywhere in our body and is either involved in mediating key processes of central and peripheral diseases or represents a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of the components of this complex system, and in particular of key receptors (like cannabinoid receptors 1 and 2) and metabolic enzymes (like fatty acid amide hydrolase and monoacylglycerol lipase), will advance our understanding of endocannabinoid signaling and activity at molecular, cellular, and system levels, providing new opportunities to treat patients.

β-Caryophyllene, a Dietary Phytocannabinoid, Alleviates Diabetic Cardiomyopathy in Mice by Inhibiting Oxidative Stress and Inflammation Activating Cannabinoid Type-2 Receptors

Diabetes mellitus (DM) and its associated complications are considered one of the major health risks globally. Among numerous complications, diabetic cardiomyopathy (DCM) is characterized by increased accumulation of lipids and reduced glucose utilization following abnormal lipid metabolism in the myocardium along with oxidative stress, myocardial fibrosis, and inflammation that eventually result in cardiac dysfunction. The abnormal metabolism of lipids plays a fundamental role in cardiac lipotoxicity following the occurrence and development of DCM. Recently, it has been revealed that cannabinoid type-2 (CB2) receptors, an essential component of the endocannabinoid system, play a crucial role in the pathogenesis of obesity, hyperlipidemia, and DM. Provided the role of CB2R in regulating the glucolipid metabolic dysfunction and its antioxidant as well as anti-inflammatory activities, we carried out the current study to investigate the protective effects of a selective CB2R agonist, β-caryophyllene (BCP), a natural dietary cannabinoid in the murine model of DCM and elucidated the underlying pharmacological and molecular mechanisms. Mice were fed a high-fat diet for 4 weeks followed by a single intraperitoneal injection of streptozotocin (100 mg/kg) to induce the model of DCM. BCP (50 mg/kg body weight) was given orally for 12 weeks. AM630, a CB2R antagonist, was given 30 min before BCP treatment to demonstrate the CB2R-dependent mechanism of BCP. DCM mice exhibited hyperglycemia, increased serum lactate dehydrogenase, impaired cardiac function, and hypertrophy. In addition, DCM mice showed alternations in serum lipids and increased oxidative stress concomitant to reduced antioxidant defenses and enhanced cardiac lipid accumulation in the diabetic heart. DCM mice also exhibited activation of TLR4/NF-κB/MAPK signaling and triggered the production of inflammatory cytokines and inflammatory enzyme mediators. However, treatment with BCP exerted remarkable protective effects by favorable modulation of the biochemical and molecular parameters, which were altered in DCM mice. Interestingly, pretreatment with AM630 abrogated the protective effects of BCP in DCM mice. Taken together, the findings of the present study demonstrate that BCP possesses the capability to mitigate the progression of DCM by inhibition of lipotoxicity-mediated cardiac oxidative stress and inflammation and favorable modulation of TLR4/NF-κB/MAPK signaling pathways mediating the CB2R-dependent mechanism.

Anandamide modulates WNT-5A/BCL-2, IP3/NFATc1, and HMGB1/NF-κB trajectories to protect against mercuric chloride-induced acute kidney injury

Endocannabinoid anandamide (AEA) has a physiological role in regulating renal blood flow, whereas its analogs ameliorated renal ischemia/reperfusion injury. Nonetheless, the role of AEA against mercuric chloride (HgCl₂)-induced renal toxicity has not been unraveled. Rats were allocated into control, HgCl₂, and HgCl₂/AEA treated groups. The administration of AEA quelled the HgCl₂-mediated increase in inositol trisphosphate (IP3) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). The endocannabinoid also signified its anti-inflammatory potential by turning off the inflammatory cascade evidenced by the suppression of high mobility group box protein-1 (HMGB1), receptor of glycated end products (RAGE), nuclear factor-κB p65 (NF-κB), and unexpectedly PPAR-γ. Additionally, the aptitude of AEA to inhibit malondialdehyde and boost glutathione points to its antioxidant capacity. Moreover, AEA by enhancing the depleted renal WNT-5A and reducing cystatin-C and KIM-1 (two kidney function parameters) partly verified its anti-apoptotic capacity, confirmed by inhibiting caspase-3 and increasing B-cell lymphoma-2 (BCL-2). The beneficial effect of AEA was mirrored by the improved architecture and kidney function evidenced by the reduction in cystatin-C, KIM-1, creatinine, BUN, and caspase1-induced activated IL-18. In conclusion, our results verify the reno-protective potential of AEA against HgCl₂-induced kidney injury by its anti-inflammatory, antioxidant, and anti-apoptotic capacities by modulating WNT-5A/BCL-2, IP3/NFATC1, HMGB-1/RAGE/NF-κB, caspase-1/IL-18, and caspase-3/BCL-2 cues.

Cannabinoid Signaling in Kidney Disease

Endocannabinoid signaling plays crucial roles in human physiology in the function of multiple systems. The two cannabinoid receptors, CB1 and CB2, are cell membrane proteins that interact with both exogenous and endogenous bioactive lipid ligands, or endocannabinoids. Recent evidence has established that endocannabinoid signaling operates within the human kidney, as well as suggests the important role it plays in multiple renal pathologies. CB1, specifically, has been identified as the more prominent ECS receptor within the kidney, allowing us to place emphasis on this receptor. The activity of CB1 has been repeatedly shown to contribute to both diabetic and non-diabetic chronic kidney disease (CKD). Interestingly, recent reports of acute kidney injury (AKI) have been attributed to synthetic cannabinoid use. Therefore, the exploration of the ECS, its receptors, and its ligands can help provide better insight into new methods of treatment for a range of renal diseases. This review explores the endocannabinoid system, with a focus on its impacts within the healthy and diseased kidney.

CBGA ameliorates inflammation and fibrosis in nephropathy

Cannabidiol (CBD) is thought to have multiple biological effects, including the ability to attenuate inflammatory processes. Cannabigerols (CBGA and its decarboxylated CBG molecule) have pharmacological profiles similar to CBD. The endocannabinoid system has recently emerged to contribute to kidney disease, however, the therapeutic properties of cannabinoids in kidney disease remain largely unknown. In this study, we determined whether CBD and CBGA can attenuate kidney damage in an acute kidney disease model induced by the chemotherapeutic cisplatin. In addition, we evaluated the anti-fibrosis effects of these cannabinoids in a chronic kidney disease model induced by unilateral ureteral obstruction (UUO). We find that CBGA, but not CBD, protects the kidney from cisplatin-induced nephrotoxicity. CBGA also strongly suppressed mRNA of inflammatory cytokines in cisplatin-induced nephropathy, whereas CBD treatment was only partially effective. Furthermore, both CBGA and CBD treatment significantly reduced apoptosis through inhibition of caspase-3 activity. In UUO kidneys, both CBGA and CBD strongly reduced renal fibrosis. Finally, we find that CBGA, but not CBD, has a potent inhibitory effect on the channel-kinase TRPM7. We conclude that CBGA and CBD possess reno-protective properties, with CBGA having a higher efficacy, likely due to its dual anti-inflammatory and anti-fibrotic effects paired with TRPM7 inhibition.

Structural basis of selective cannabinoid CB2 receptor activation

Cannabinoid CB2 receptor (CB2R) agonists are investigated as therapeutic agents in the clinic. However, their molecular mode-of-action is not fully understood. Here, we report the discovery of LEI-102, a CB2R agonist, used in conjunction with three other CBR ligands (APD371, HU308, and CP55,940) to investigate the selective CB2R activation by binding kinetics, site-directed mutagenesis, and cryo-EM studies. We identify key residues for CB2R activation. Highly lipophilic HU308 and the endocannabinoids, but not the more polar LEI-102, APD371, and CP55,940, reach the binding pocket through a membrane channel in TM1-TM7. Favorable physico-chemical properties of LEI-102 enable oral efficacy in a chemotherapy-induced nephropathy model. This study delineates the molecular mechanism of CB2R activation by selective agonists and highlights the role of lipophilicity in CB2R engagement. This may have implications for GPCR drug design and sheds light on their activation by endogenous ligands.

Cannabis Use and Risk of Acute Kidney Injury in Patients with Advanced Chronic Kidney Disease Transitioning to Dialysis

Background: The current social and legal landscape is likely to foster the medicinal and recreational use of cannabis. Synthetic cannabinoid use is associated with acute kidney injury (AKI) in case reports; however, the association between natural cannabis use and AKI risk in patients with advanced chronic kidney disease (CKD) is unknown. Materials and Methods: From a nationally representative cohort of 102,477 U.S. veterans transitioning to dialysis between 2007 and 2015, we identified 2215 patients with advanced CKD who had undergone urine toxicology (UTOX) tests within a year before dialysis initiation and had inpatient serial serum creatinine levels measured within 7 days after their UTOX test. The exposure of interest was cannabis use compared with no use as ascertained by the UTOX test. We examined the association of this exposure with AKI using logistic regression and inverse probability of treatment weighting with extensive adjustment for potential confounders. Results: The mean age of the overall cohort was 61 years; 97% were males, 51% were African Americans, 97% had hypertension, 76% had hyperlipidemia, and 75% were diabetic. AKI occurred in 56% of the cohort, and in multivariable-adjusted analysis, cannabis use (when compared with no substance use) was not associated with significantly higher odds of AKI (odds ratio 0.85, 95% confidence interval 0.38-1.87; p=0.7). These results were robust to various sensitivity analyses. Conclusions: In this observational study examining patients with advanced CKD, cannabis use was not associated with AKI risk. Additional studies are needed to characterize the impact of cannabis use on risk of kidney disease and injury.

Cannabinoids in the Modulation of Oxidative Signaling

Cannabis sativa-derived compounds, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), and components of the endocannabinoids system, such as N-arachidonoylethanolamide (anandamide, AEA) and 2-arachidonoylglycerol (2-AG), are extensively studied to investigate their numerous biological effects, including powerful antioxidant effects. Indeed, a series of recent studies have indicated that many disorders are characterized by alterations in the intracellular antioxidant system, which lead to biological macromolecule damage. These pathological conditions are characterized by an unbalanced, and most often increased, reactive oxygen species (ROS) production. For this study, it was of interest to investigate and recapitulate the antioxidant properties of these natural compounds, for the most part CBD and THC, on the production of ROS and the modulation of the intracellular redox state, with an emphasis on their use in various pathological conditions in which the reduction of ROS can be clinically useful, such as neurodegenerative disorders, inflammatory conditions, autoimmunity, and cancers. The further development of ROS-based fundamental research focused on cannabis sativa-derived compounds could be beneficial for future clinical applications.

Selective CB2 Receptor Agonist, HU-308, Reduces Systemic Inflammation in Endotoxin Model of Pneumonia-Induced Acute Lung Injury

Acute respiratory distress syndrome (ARDS) and sepsis are risk factors contributing to mortality in patients with pneumonia. In ARDS, also termed acute lung injury (ALI), pulmonary immune responses lead to excessive pro-inflammatory cytokine release and aberrant alveolar neutrophil infiltration. Systemic spread of cytokines is associated with systemic complications including sepsis, multi-organ failure, and death. Thus, dampening pro-inflammatory cytokine release is a viable strategy to improve outcome. Activation of cannabinoid type II receptor (CB₂) has been shown to reduce cytokine release in various in vivo and in vitro studies. Herein, we investigated the effect of HU-308, a specific CB₂ agonist, on systemic and pulmonary inflammation in a model of pneumonia-induced ALI. C57Bl/6 mice received intranasal endotoxin or saline, followed by intravenous HU-308, dexamethasone, or vehicle. ALI was scored by histology and plasma levels of select inflammatory mediators were assessed by Luminex assay. Intravital microscopy (IVM) was performed to assess leukocyte adhesion and capillary perfusion in intestinal and pulmonary microcirculation. HU-308 and dexamethasone attenuated LPS-induced cytokine release and intestinal microcirculatory impairment. HU-308 modestly reduced ALI score, while dexamethasone abolished it. These results suggest administration of HU-308 can reduce systemic inflammation without suppressing pulmonary immune response in pneumonia-induced ALI and systemic inflammation.

Pharmacological Aspects and Biological Effects of Cannabigerol and Its Synthetic Derivatives

Cannabigerol (CBG) is a cannabinoid from the plant Cannabis sativa that lacks psychotomimetic effects. Its precursor is the acidic form, cannabigerolic acid (CBGA), which is, in turn, a biosynthetic precursor of the compounds cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). CBGA decarboxylation leads to the formation of neutral cannabinoid CBG, through a chemical reaction catalyzed by heat. On the basis of the growing interest in CBG and with the aim of highlighting scientific information on this phytocannabinoid, we focused the content of this article on its pharmacokinetic and pharmacodynamic characteristics and on its principal pharmacological effects. CBG is metabolized in the liver by the enzyme CYP2J2 to produce hydroxyl and di-oxygenated products. CBG is considered a partial agonist at the CB1 receptor (R) and CB2R, as well as a regulator of endocannabinoid signaling. Potential pharmacological targets for CBG include transient receptor potential (TRP) channels, cyclooxygenase (COX-1 and COX-2) enzymes, cannabinoid, 5-HT1A, and alpha-2 receptors. Pre-clinical findings show that CBG reduces intraocular pressure, possesses antioxidant, anti-inflammatory, and anti-tumoral activities, and has anti-anxiety, neuroprotective, dermatological, and appetite-stimulating effects. Several findings suggest that research on CBG deserves to be deepened, as it could be used, alone or in association, for novel therapeutic approaches for several disorders.

The Cannabinoid-2 receptor agonist, 1-phenylisatin, protects against cisplatin-induced nephrotoxicity in mice

AIM

The present study investigated the potential protective effect of a selective Cannabinoid-2 (CB2) receptor agonist, 1-phenylisatin, in acute nephrotoxicity induced by cisplatin.

MATERIALS AND METHODS

Animals were arranged into 5 groups. Group I; normal saline, group II; 1-phenylisatin for 7 days, group III: received a single injection of cisplatin (20 mg/kg, i.p.) on day 5, group IV: 1-phenylisatin for 7 days and cisplatin on day 5 and group V: AM630, CB2 antagonist, 15 min before 1-phenylisatin for 7 days and a single injection of cisplatin on day 5. Mice were sacrificed 72 h after cisplatin injection. Kidneys were isolated for histopathological and biochemical analyses. Nephrotoxicity parameters including serum creatinine and urea were assessed as well as histopathological examination was done. Also, Oxidative stress markers; MDA and GSH, inflammatory markers; TNF-α, NF-κB (p65), MCP-1, MIP-2, and ICAM-1, along with apoptotic markers, Bax, Bcl2, and caspase-3 were studied. Further, CB2 receptor expression was investigated.

KEY FINDINGS

Cisplatin injection increased serum creatinine and urea levels, and increased lipid peroxidation, decreased glutathione level and increased the renal expression of pro-inflammatory markers, TNF-α, NF-κB, MCP-1, MIP-2, and ICAM-1, along with increased apoptotic markers and significantly reduced the expression of the anti-apoptotic Bcl2. Pretreatment with 1-phenylisatin significantly counteracted these effects. The CB2 receptor antagonist; AM630, increased the renal expression of caspase-3 and Bax whereas Bcl2 expression decreased.

SIGNIFICANCE

1-Phenylisatin protected against cisplatin-induced nephrotoxicity owing to its anti-apoptotic, anti-inflammatory, and antioxidant effects. These actions were mostly mediated through CB2 receptor.

The evaluation of citral effects on experimental unilateral testicular ischemia/reperfusion injury

This investigation aimed to evaluate the defensive impacts of citral on ischemia/reperfusion (I/R) injury induced by testicular torsion/detorsion (T/D) in rats in an experimental model. The grouping of subjects was as follows: (1) sham, (2) T/D, (3) and (4) T/D plus citral 150 and 300 mg/kg, respectively, and (5) intact (citral 300 mg/kg). T/D was performed by testicular 720° turning for 2 h and then detorsion for 24 h. Blood serum was obtained to assess testosterone and oxidative stress markers, epididymal sperms were collected for sperm staining and sperm analysis, and testicular tissues were examined for histopathology. T/D damage was associated with a remarkable decline in sperm total count, viability, and some velocity parameters in comparison to the sham group (p < 0.05), which could be reversed significantly by citral (p < 0.05). Histopathologically, T/D damage caused severe oedema, haemorrhage, inflammation, and seminiferous tubules disruption, while citral improved significantly the mean seminiferous tubular diameter, Cosentino's score, and Johnsen's score (p < 0.05). I/R injury was associated with significant increased malondialdehyde and oxidative stress index, and also significant reduced total antioxidant capacity and testosterone versus the sham group (p < 0.05), which all were prevented significantly by citral administration (p < 0.05). The outcomes greatly proved that testicular I/R injury could be significantly prevented by citral.

Mechanisms of podocyte injury and implications for diabetic nephropathy

Albuminuria is the hallmark of both primary and secondary proteinuric glomerulopathies, including focal segmental glomerulosclerosis (FSGS), obesity-related nephropathy, and diabetic nephropathy (DN). Moreover, albuminuria is an important feature of all chronic kidney diseases (CKDs). Podocytes play a key role in maintaining the permselectivity of the glomerular filtration barrier (GFB) and injury of the podocyte, leading to foot process (FP) effacement and podocyte loss, the unifying underlying mechanism of proteinuric glomerulopathies. The metabolic insult of hyperglycemia is of paramount importance in the pathogenesis of DN, while insults leading to podocyte damage are poorly defined in other proteinuric glomerulopathies. However, shared mechanisms of podocyte damage have been identified. Herein, we will review the role of haemodynamic and oxidative stress, inflammation, lipotoxicity, endocannabinoid (EC) hypertone, and both mitochondrial and autophagic dysfunction in the pathogenesis of the podocyte damage, focussing particularly on their role in the pathogenesis of DN. Gaining a better insight into the mechanisms of podocyte injury may provide novel targets for treatment. Moreover, novel strategies for boosting podocyte repair may open the way to podocyte regenerative medicine.

Acute and long-term effects of cannabinoids on hypertension and kidney injury

Cannabinoids and their endogenous and synthetic analogs impact blood pressure and contribute to the incidence of hypertension. It was previously reported that the endocannabinoid system plays an important role in developing hypertension; however, it was also shown that cannabinoids elicit profound hypotension associated with hemorrhagic, cardiogenic, and endotoxic shock. This study aimed to test acute and chronic effects of an endogenous ligand of cannabinoid receptor anandamide (AEA) on blood pressure and kidney injury in vivo in conscious Dahl salt-sensitive (SS) rats. We demonstrated that acute i.v. bolus administration of a low or a high doses (0.05 or 3 mg/kg) of AEA did not affect blood pressure for 2 h after the injection in Dahl SS rats fed a normal salt diet (0.4% NaCl). Neither low nor high doses of AEA had any beneficial effects on blood pressure or kidney function. Furthermore, hypertensive rats fed a HS diet (8% NaCl) and chronically treated with 3 mg/kg of AEA exhibited a significant increase in blood pressure accompanied by increased renal interstitial fibrosis and glomerular damage at the late stage of hypertension. Western blot analyses revealed increased expression of Smad3 protein levels in the kidney cortex in response to chronic treatment with a high AEA dose. Therefore, TGF-β1/Smad3 signaling pathway may play a crucial role in kidney injury in SS hypertension during chronic treatment with AEA. Collectively, these data indicate that prolonged stimulation of cannabinoid receptors may result in aggravation of hypertension and kidney damage.

Intertwined associations between oxidative and nitrosative stress and endocannabinoid system pathways: Relevance for neuropsychiatric disorders

The endocannabinoid system (ECS) appears to regulate metabolic, cardiovascular, immune, gastrointestinal, lung, and reproductive system functions, as well as the central nervous system. There is also evidence that neuropsychiatric disorders are associated with ECS abnormalities as well as oxidative and nitrosative stress pathways. The goal of this mechanistic review is to investigate the mechanisms underlying the ECS's regulation of redox signalling, as well as the mechanisms by which activated oxidative and nitrosative stress pathways may impair ECS-mediated signalling. Cannabinoid receptor (CB)1 activation and upregulation of brain CB2 receptors reduce oxidative stress in the brain, resulting in less tissue damage and less neuroinflammation. Chronically high levels of oxidative stress may impair CB1 and CB2 receptor activity. CB1 activation in peripheral cells increases nitrosative stress and inducible nitric oxide (iNOS) activity, reducing mitochondrial activity. Upregulation of CB2 in the peripheral and central nervous systems may reduce iNOS, nitrosative stress, and neuroinflammation. Nitrosative stress may have an impact on CB1 and CB2-mediated signalling. Peripheral immune activation, which frequently occurs in response to nitro-oxidative stress, may result in increased expression of CB2 receptors on T and B lymphocytes, dendritic cells, and macrophages, reducing the production of inflammatory products and limiting the duration and intensity of the immune and oxidative stress response. In conclusion, high levels of oxidative and nitrosative stress may compromise or even abolish ECS-mediated redox pathway regulation. Future research in neuropsychiatric disorders like mood disorders and deficit schizophrenia should explore abnormalities in these intertwined signalling pathways.

The protective impacts of Spirulina platensis against cisplatin-induced renal injury through the regulation of oxidative stress, pro-inflammatory cytokines and Bax/Bcl2

One of the main antineoplastic chemotherapy medications is cisplatin, of which nephropathy is a major side effect. In this current study, we aim to investigate the molecular protective effect of Spirulina platensis (SP) on cisplatin-induced nephrotoxicity. In total, 48 healthy male albino rats were allocated into 4 groups. Group 1 received saline intraperitoneally (IP) twice per week (normal rats). Group 2 received SP (100 mg/kg BW orally). Group 3 were injected with cisplatin (1.5 mg/kg IP) twice per week. Group 4 received SP and on the 4th day received cisplatin (1.5 mg/kg IP) for 21 days. After 3 weeks of experiment, blood and renal tissues were taken for serum analysis, gene expression using qRT-polymerase chain reaction, and renal histopathology. As per our findings, it was found that SP significantly ameliorated the alterations in body weight, relative kidney weight, and the disturbance in examined renal markers. Furthermore, SP recovered and restored cisplatin-induced oxidative stress biomarkers (MDA and NO) and antioxidant activity (SOD and GSH) and cisplatin-induced upregulation in the gene expression of TNF-α, inducible nitric oxide synthase, TGF1-β, IL-1β, and IL-6. Interestingly, these gene expressions were ameliorated by the SP pre-administration. Furthermore, cisplatin upregulated pro-apoptotic gene Bax, whereas it downregulated anti-apoptotic gene Bcl2. Interestingly, SP mitigated this alteration in apoptosis and anti-apoptotic associated genes. Renal histopathology revealed the protective impacts of SP against cisplatin-induced severe glomerular congestion, hemorrhage, inflammatory cell infiltration, degeneration, and severe necrosis in renal glomeruli and tubules. In conclusion, SP has a protective effect against cisplatin-induced renal damage through modulating oxidative stress and anti-inflammatory, anti-necrotic, and anti-apoptotic-associated genes.

Activation of cannabinoid-2 receptor protects against Pseudomonas aeruginosa induced acute lung injury and inflammation

BACKGROUND

Bacterial pneumonia is a major risk factor for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Pseudomonas aeruginosa (PA), an opportunistic pathogen with an increasing resistance acquired against multiple drugs, is one of the main causative agents of ALI and ARDS in diverse clinical settings. Given the anti-inflammatory role of the cannabinoid-2 receptor (CB2R), the effect of CB2R activation in the regulation of PA-induced ALI and inflammation was tested in a mouse model as an alternative to conventional antibiotic therapy.

METHODS

In order to activate CB2R, a selective synthetic agonist, JWH133, was administered intraperitoneally (i.p.) to C57BL/6J mice. Furthermore, SR144528 (a selective CB2R antagonist) was administered in combination with JWH133 to test the specificity of the CB2R-mediated effect. PA was administered intratracheally (i.t.) for induction of pneumonia in mice. At 24 h after PA exposure, lung mechanics were measured using the FlexiVent system. The total cell number, protein content, and neutrophil population in the bronchoalveolar lavage fluid (BALF) were determined. The bacterial load in the whole lung was also measured. Lung injury was evaluated by histological examination and PA-induced inflammation was assessed by measuring the levels of BALF cytokines and chemokines. Neutrophil activation (examined by immunofluorescence and immunoblot) and PA-induced inflammatory signaling (analyzed by immunoblot) were also studied.

RESULTS

CB2R activation by JWH133 was found to significantly reduce PA-induced ALI and the bacterial burden. CB2R activation also suppressed the PA-induced increase in immune cell infiltration, neutrophil population, and inflammatory cytokines. These effects were abrogated by a CB2R antagonist, SR144528, further confirming the specificity of the CB2R-mediated effects. CB2R-knock out (CB2RKO) mice had a significantly higher level of PA-induced inflammation as compared to that in WT mice. CB2R activation diminished the excess activation of neutrophils, whereas mice lacking CB2R had elevated neutrophil activation. Pharmacological activation of CB2R significantly reduced the PA-induced NF-κB and NLRP3 inflammasome activation, whereas CB2KO mice had elevated NLRP3 inflammasome.

CONCLUSION

Our findings indicate that CB2R activation ameliorates PA-induced lung injury and inflammation, thus paving the path for new therapeutic avenues against PA pneumonia.

Cannabinoid Drugs-Related Neuroprotection as a Potential Therapeutic Tool Against Chemotherapy-Induced Cognitive Impairment

In recent years, and particularly associated with the increase of cancer patients’ life expectancy, the occurrence of cancer treatment sequelae, including cognitive impairments, has received considerable attention. Chemotherapy-induced cognitive impairments (CICI) can be observed not only during pharmacological treatment of the disease but also long after cessation of this therapy. The lack of effective tools for its diagnosis together with the limited treatments currently available for alleviation of the side-effects induced by chemotherapeutic agents, demonstrates the need of a better understanding of the mechanisms underlying the pathology. This review focuses on the comprehensive appraisal of two main processes associated with the development of CICI: neuroinflammation and oxidative stress, and proposes the endogenous cannabinoid system (ECS) as a new therapeutic target against CICI. The neuroprotective role of the ECS, well described in other cognitive-related neuropathologies, seems to be able to reduce the activation of pro-inflammatory cytokines involved in the neuroinflammatory supraspinal processes underlying CICI. This review also provides evidence supporting the role of cannabinoid-based drugs in the modulation of oxidative stress processes that underpin cognitive impairments, and warrant the investigation of endocannabinoid components, still unknown, that may mediate the molecular mechanism behind this neuroprotective activity. Finally, this review points forward the urgent need of research focused on the understanding of CICI and the investigation of new therapeutic targets.

Endothelial peroxynitrite causes disturbance of neuronal oscillations by targeting caspase-1 in the arcuate nucleus

Severe anorexia limits the clinical application of cisplatin, and even leads to the discontinuation of treatment. However, the mechanisms underlying cisplatin-induced anorexia are unknown. Herein, we demonstrated that cisplatin could affect neuronal gamma oscillations and induce abnormal neuronal theta-gamma phase-amplitude coupling in the arcuate nucleus (Arc) of the hypothalamus, and these findings were associated with significantly decreased food intake and weight loss in mice. Chemogenetic activation of AgRP neurons in the Arc reversed the cisplatin-induced food intake reduction in mice. We further demonstrated that endothelial peroxynitrite (ONOO⁻) formation in the Arc induced nitrosative stress following cisplatin treatment via a previously uncharacterized pathway involving neuronal caspase-1 activation. Strikingly, treatment with the ONOO⁻ scavenger uric acid (UA) reversed the reduced action potential (AP) frequency of AgRP neurons and increased the AP frequency of POMC neurons induced by SIN1, a donor of ONOO⁻, in the Arc, as determined by whole-cell patch-clamp electrophysiological recording. Consistent with these findings, UA treatment effectively alleviated cisplatin-induced dysfunction of neuronal oscillations and neuronal theta-gamma phase-amplitude coupling in the Arc of mice. Taken together, these results suggest, for the first time, that targeting the overproduction of endothelial ONOO⁻ can regulate cisplatin-induced neurotoxicity through neuronal caspase-1, and thereby serve as a potential therapeutic approach to alleviate chemotherapy-induced anorexia and weight loss.

•

Endothelial ONOO^– induced the abnormal neuronal oscillations following cisplatin treatment through caspase-1 in the Arc.

•

ONOO^– scavenger UA could attenuate cisplatin-induced neurotoxicity and caspase-1 activation in the Arc.

•

Targeting endothelial ONOO^– provided a promising approach to alleviate chemotherapy-induced anorexia and weight loss.

Cannabinoid Receptor 2 Agonism is Capable of Preventing Lipopolysaccharide Induced Decreases of Cochlear Microcirculation - A Potential Approach for Inner Ear Pathologies

HYPOTHESIS

The ability of JWH-133, an agonist at the cannabinoid receptor 2, to abrogate the effects of lipopolysaccharide on cochlear microcirculation was investigated.

BACKGROUND

Cochlear inflammation and subsequent impairment of microcirculation is part of numerous pathologies affecting inner ear function, including suppurative labyrinthitis, noise trauma, and sudden sensorineural hearing loss. One way of causing cochlear inflammation is exposing the cochlea to lipopolysaccharide, a bacterial endotoxin.

METHODS

Twenty Dunkin-hartley guinea pigs were divided into four groups of five animals each. Two groups received topic treatment with JWH-133 and two received treatment with placebo. One group that had been treated with JWH-133 and one with placebo were then exposed to lipopolysaccharide or placebo, respectively. Cochlear microcirculation was quantified before, in between and after treatments by in vivo fluorescence microscopy.

RESULTS

Significantly different changes in cochlear blood flow were only seen in the group that was treated with placebo and subsequently lipopolysaccharide. Every other group showed no significant change in cochlear blood flow.

CONCLUSION

JWH-133 is capable of abrogating the effects of lipopolysaccharide on cochlear microcirculation. It may therefore be clinical interest in treating numerous inflammation associated cochlear pathologies.

Mechanism Prediction of Astragalus membranaceus against Cisplatin-Induced Kidney Damage by Network Pharmacology and Molecular Docking

Background

Cisplatin is a frequently used and effective chemotherapy drug in clinical practice, but severe side effects limit its use, among which nephrotoxicity is considered the most serious and prolonged damage to the body. Astragalus membranaceus (AM) is a well-known herbal medicine, and modern pharmacological studies have confirmed its antioxidant, immunomodulatory, and antiapoptotic effects. Clinical studies have shown that AM and its active components can attenuate cisplatin-induced kidney damage, but the molecular mechanism has not been fully expounded.

Materials and Methods

First, the components and targets information of AM were collected from the TCMSP, and the relevant targets of cisplatin-induced kidney damage were accessed from the GeneCards and OMIM databases. Then, the core targets were selected by the Venn diagram and network topology analysis, which was followed by GO and KEGG pathway enrichment analysis. Finally, we construct a component-target-pathway network. Furthermore, molecular docking was carried out to identify the binding activity between active components and key targets.

Results

A total of 20 active components and 200 targets of AM and 646 targets related to cisplatin-induced kidney damage were obtained. 91 intersection targets were found between AM and cisplatin-induced kidney damage. Then, 16 core targets were identified, such as MAPK1, TNF-α, and p53. Furthermore, GO and KEGG pathway enrichment analysis suggested that MAPK, Toll-like receptor, and PI3K-Akt signaling pathways may be of significance in the treatment of cisplatin-induced kidney damage by AM. Molecular docking indicated that quercetin and kaempferol had high binding affinities with many core targets.

Conclusion

In summary, the active components, key targets, and signaling pathways of AM in the treatment of cisplatin-induced kidney damage were predicted in this study, which contributed to the development and application of AM.

Marijuana Use and In-Hospital Outcomes After Percutaneous Coronary Intervention in Michigan, United States

OBJECTIVES

The aim of this study was to evaluate the association between reported marijuana use and post-percutaneous coronary intervention (PCI) in-hospital outcomes.

BACKGROUND

Marijuana use is increasing as more states in the United States legalize its use for recreational and medicinal purposes. Little is known about the frequency of use and relative safety of marijuana among patients presenting for PCI.

METHODS

The authors analyzed Blue Cross Blue Shield of Michigan Cardiovascular Consortium PCI registry data between January 1, 2013, and September 30, 2016. One-to-one propensity matching and multivariable logistic regression were used to adjust for differences between patients with or without reported marijuana use, and rates of post-PCI complications were compared.

RESULTS

Among 113,477 patients, 3,970 reported marijuana use. Compared with those without reported marijuana use, patients with reported marijuana use were likely to be younger (53.9 years vs 65.8 years), to use tobacco (73.0% vs 26.8%), to present with ST-segment elevation myocardial infarction (27.3% vs 15.9%), and to have fewer cardiovascular comorbidities. After matching, compared with patients without reported marijuana use, those with reported marijuana use experienced significantly higher risks for bleeding (adjusted odds ratio [aOR]: 1.54; 95% confidence interval [CI]: 1.20-1.97; P < 0.001) and cerebrovascular accident (aOR: 11.01; 95% CI: 1.32-91.67; P = 0.026) and a lower risk for acute kidney injury (aOR: 0.61; 95% CI: 0.42-0.87; P = 0.007). There were no significant differences in risks for transfusion and death.

CONCLUSIONS

A modest fraction of patients undergoing PCI used marijuana. Reported marijuana use was associated with higher risks for cerebrovascular accident and bleeding and a lower risk for acute kidney injury after PCI. Clinicians and patients should be aware of the higher risk for post-PCI complications in these patients.

CB2-mediated attenuation of nucleus pulposus degeneration via the amelioration of inflammation and oxidative stress in vivo and in vitro

Background

Nucleus pulposus cell (NPC) degeneration is widely accepted as one of the major causes of intervertebral disc (IVD) degeneration (IVDD). The pathogenesis of IVDD is complex and consists of inflammation, oxidative stress, and the loss of extracellular matrix (ECM). Cannabinoid type 2 receptor (CB2) has been shown to be involved in the pathological mechanism of a variety of diseases due to its anti-inflammatory effects and antioxidative stress capacity.

Method

In Vitro, H₂O₂ was used to induce degeneration of nucleus pulposus cells, mRNA and protein expression level was determined by RT-PCR and Western Blot, and Immunocytochemical staining were used to detect expression of collagen II, aggrecan, MMP3/13, superoxide dismutase 2 (SOD2) and inducible nitric oxide synthase (iNOS). In vivo, the potential therapeutic effect of CB2 was detected in the rat acupuncture model.

Result

In vitro, we found that the CB2 agonist (JWH133) treatment reduced the oxidative stress level in NPCs induced by hydrogen peroxide (H₂O₂) treatment. Furthermore, the expression of inflammatory cytokines was also decreased by JWH133 treatment. We found that collagen II and aggrecan expression was preserved, whereas matrix metalloproteinase levels were reduced. In vivo, we established a rat model by needle puncture. Imaging assessment revealed that the disc height index (DHI) and morphology of IVD were significantly improved, and the disc degeneration process was delayed by treatment of JWH133. Furthermore, immunohistochemical (IHC) staining revealed that JWH133 could inhibit the degradation of collagen II and decrease the expression of MMP3.

Conclusions

The experiment indicates the oxidative stress and inflammatory response of rat NPCs induced by H₂O₂ could be inhibited by activating CB2. This study reveals that CB2 activation can effectively delay the development of IVDD, providing an effective therapeutic target for IVDD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00351-x.

The Critical Role of Cannabinoid Receptor 2 in URB602-Induced Protective Effects Against Renal Ischemia-Reperfusion Injury in the Rat

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) and even induces remote organ damage. Accumulating proofs demonstrates that the endocannabinoid system may provide a promising access for treatment strategy of renal IRI associated AKI. In the current study, using the established renal IRI model of rat, we tested the hypothesis that pretreatment of URB602, 30 min before renal IRI, alleviates kidney injury and relevant distant organ damage via limiting oxidative stress and inflammation. Using Western blot analysis and LC-MS/MS, renal IRI showed to increase the levels of 2-arachidonoylglycerol (2-AG) in kidneys as well as COX-2, PGE2, TXA2, and decrease N-arachidonoylethanolamine (anandamide, AEA); the expressions of renal cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) were unchanged. The URB602 pretreatment in renal IRI, further enhanced renal 2-AG which is high affinity to both CB1 and CB2, and reduced renal COX-2 which is involved in the regulation of renal perfusion and inflammation. AM630 (CB2 antagonist) almost blocked all the antioxidant, anti-inflammatory and nephroprotective effects of URB602, whereas AM251 (CB1 antagonist) showed limited influence, and parecoxib (COX-2 inhibitor) slightly ameliorated renal function at the dose of 10 mg/kg. Taken together, our data indicate that URB602 acts as a reactive oxygen species scavenger and anti-inflammatory media in renal IRI mainly depending on the activation of CB2.

Protective Effect of Calcium Dobesilate on Induced AKI in Severely Burned Mice

BACKGROUND

Early acute kidney injury (AKI) predicts a high mortality rate in severely burned patients. However, the pathophysiology of early AKI induced by severe burn has not been well-defined. This study was designed to examine the protective effects of calcium dobesilate (CaD) against severe burn-induced early AKI in mice and explore the mechanism.

METHODS

The shaved backs of mice were immersed in 100°C water for 10 s to make severe burn (40% of the total body surface area). CD-57 male mice were randomly divided into sham, burn, burn + vehicle, and burn + CaD groups. Renal function, reactive oxygen species generation, tubular necrosis, and phosphorylation of mitogen-activated protein kinase, protein kinase B (Akt), and nuclear factor (NF)-κB were measured at 24 and 48 h after the burn. Renal histology, ELISA, qRT-PCR, and Western blotting were performed on the renal tissue of mice to examine the effects and mechanisms at 24 and 48 h after the burn.

RESULTS

Tubular damage, cast formation, and elevations of serum creatinine, BUN, and renal tissue kidney injury molecule 1 levels were all observed in the burned mice, and these were all alleviated in the mice with CaD treatment. In addition, the levels of oxidation-reduction potential and malondialdehyde were decreased, while the activities of the endogenous antioxidative enzymes were increased in the kidney tissues from the mice after CaD treatment. Furthermore, the activities of Akt, p38, extracellular sign-regulated kinase, Jun N-terminal kinase, and NF-κB signaling were increased in the kidney of burned mice and normalized after CaD treatment.

CONCLUSION

This study has established, for the first time, the protective effect of CaD against early AKI in severely burned mice. CaD may exert its protective effect through alleviating oxidative stress, apoptosis, and inflammation, as well as modulating some signaling pathways in the kidney.

Comparative study on protective effect of different selenium sources against cadmium-induced nephrotoxicity via regulating the transcriptions of selenoproteome

Cadmium (Cd) is a ubiquitous environmental pollutant, which mainly input to the aquatic environment through discharge of industrial and agricultural waste, can be a threat to human and animal health. Selenium (Se) possesses a beneficial role in protecting animals and ameliorating the toxic effects of Cd. However, the comparative antagonistic effects of different Se sources such as inorganic, organic Se and nano-form Se on Cd toxicity are still under-investigated. Hence, the purpose of this study was to evaluate the comparative of Se sources antagonism on Cd-induced nephrotoxicity via oxidative stress and selenoproteome transcription. In the present study, Cd-diet disturbed in the system balance of 5 trace elements (Zinc (Zn), copper (Cu), Iron (Fe), Se, Cd) and impaired renal function. Se sources, including nano- Se (NS), Se- yeast (SY), sodium selenite (SS) and mixed selenium (MS) significantly recovered the balance of 4 trace elements (Zn, Cu, Cd, Se) and renal impaired indexes (blood urea nitrogen (BUN) and creatinine (CREA)). Histological appearance of Cd-treated kidney indicated renal tubular epithelial vacuoles, particle degeneration and enlarged capsular space. Ultrastructure observation results illustrated that Cd-induced mitochondrial cristae reduction, membrane disappearance, and nuclear deformation. Treatment with Se sources, NS appeared a better impact on improving kidney tissues against the pathological alterations resulting from Cd administration. Meanwhile, NS reflected a significant impact on relieving Cd-induced kidney oxidative damage, and significantly restored the antioxidant defense system of the body. Our findings also showed NS ameliorated the Cd-induced downtrends expression of selenoproteome and selenoprotein synthesis related transcription factors. Overall, NS was the most effective Se source in avoiding of Cd cumulative toxicity, improving antioxidant capacity and regulating of selenoproteome transcriptome and selenoprotein synthesis related transcription factors expression, which contributes to ameliorate Cd-induced nephrotoxicity in chickens. These results demonstrated diet supplement with NS may prove to be an effective approach for alleviating Cd toxicity and minimizing Cd -induced health risk.

Cannabinoid receptor type 2 ligands: an analysis of granted patents since 2010

The G-protein-coupled cannabinoid receptor type 2 (CB2R) is a key element of the endocannabinoid (EC) system. EC/CB2R signaling has significant therapeutic potential in major pathologies affecting humans such as allergies, neurodegenerative disorders, inflammation or ocular diseases. CB2R agonism exerts anti-inflammatory and tissue protective effects in preclinical animal models of cardiovascular, gastrointestinal, liver, kidney, lung and neurodegenerative disorders. Existing ligands can be subdivided into endocannabinoids, cannabinoid-like and synthetic CB2R ligands that possess various degrees of potency on and selectivity against the cannabinoid receptor type 1. This review is an account of granted CB2R ligand patents from 2010 up to the present, which were surveyed using Derwent Innovation®.

β-Caryophyllene, a natural bicyclic sesquiterpene attenuates β-adrenergic agonist-induced myocardial injury in a cannabinoid receptor-2 dependent and independent manner

The downregulation of cannabinoid type-2 receptors (CB2R) have been reported in numerous diseases including cardiovascular diseases (CVDs). The activation of CB2R has recently emerged as an important therapeutic target to mitigate myocardial injury. We examined whether CB2R activation can protect against isoproterenol (ISO)-induced myocardial injury (MI) in rats. In the present study, we investigated the cardioprotective effect of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid in rat model of MI. Rats were pre- and co-treated with BCP (50 mg/kg, orally) twice daily for 10 days along with subcutaneous injection of ISO (85 mg/kg) at an interval of 24 h for two days (9th and 10th days). AM630 (1 mg/kg), a CB2 receptor antagonist, was injected intraperitoneal as a pharmacological challenge prior to BCP treatment to reveal CB2R-mediated cardioprotective mechanisms of BCP. Desensitization of beta-adrenergic receptor (β-AR) signaling, receptor phosphorylation and recruitment of adapter β-arrestins were observed in ISO-induced MI in rats. ISO injections caused impaired cardiac function, elevated the levels of serum cardiac marker enzymes, and enhanced oxidative stress markers along with altered PI3K/Akt and NrF2/Keap1/HO-1 signaling pathways. ISO also promoted lysosomal dysfunction along with activation of NLRP3 inflammasomes and TLR4-NFκB/MAPK signaling and triggered rise in proinflammatory cytokines. There was a concomitant mitochondrial dysfunction followed by the activation of endoplasmic reticulum (ER) stress-mediated Hippo signaling and intrinsic pathway of apoptosis as well as altered autophagic flux/mTOR signaling in ISO-induced MI. Furthermore, ISO also triggered dyslipidemia evidenced by altered lipids, lipoproteins and lipid marker enzymes along with ionic homeostasis malfunction. However, treatment with BCP resulted in significant protective effects on all biochemical and molecular parameters analyzed. The cardioprotective effects were further strengthened by preservation of cardiomyocytes and cell organelles as observed in histopathological and ultrastructural studies. Interestingly, treatment with AM630, a CB2R antagonist was observed to abrogate the protective effects of BCP on the biochemical and molecular parameters except hyperlipidemia and ionic homeostasis in ISO-induced MI in rats. The present study findings demonstrate that BCP possess the potential to protect myocardium against ISO-induced MI in a CB2-dependent and independent manner.

An inherently kidney-targeting near-infrared fluorophore based probe for early detection of acute kidney injury

Acute kidney injury (AKI) is common in hospital patients. Delayed diagnosis and treatment of AKI due to the lack of efficient early diagnosis is an important cause of its high mortality. While fluorescence imaging seems promising to non-intrusively interrogate AKI-related biomarkers, the low kidney contrast of many fluorophores conferred by their relatively low abundance of distribution in the kidney limits their application for AKI detection. Herein, we discovered a near-infrared fluorophore with inherent kidney-targeting ability. Based on this fluorophore, a fluorogenic probe (KNP-1) was developed by targeting peroxynitrite (ONOO^-), which is upregulated at the early onset of AKI. KNP-1 exhibits desirable kidney distribution after intravenous administration and is fluorescent only after activation by ONOO^-. These properties lead to excellent kidney contrast imaging results. KNP-1 is capable of detecting both nephrotoxin-induced and ischemia-reperfusion injury-induced AKI in live mice. Temporally resolved imaging of AKI-disease model mice with KNP-1 suggests a gradual increase in renal ONOO^- levels with disease progression. Notably, the upregulation of ONOO^- can be observed at least 24 h earlier than the clinically popular sCr and BUN methods. Blocking ONOO^- generation also proves beneficial. These results highlight the applicability of this inherently tissue targeting-based strategy for designing probes with desirable imaging contrast; potentiate ONOO^- as a biomarker and target for AKI early diagnosis and medical intervention; and imply the clinical relevance of KNP-1 for AKI early detection.

Current advances in the nano-delivery of celastrol for treating inflammation-associated diseases

Inflammation is ubiquitous in the body, and uncontrolled inflammation often contributes to various diseases. Celastrol, a compound isolated from a Chinese medicinal herb, holds great potential in treating multiple inflammation-associated diseases. However, its further clinical use is limited by its poor solubility, bioavailability, and high organ toxicity. With the advancement of nanotechnology, the nano-delivery of celastrol can effectively improve its oral bioavailability, maximize its efficacy and minimize its side effects. Here, we summarize the roles of celastrol in the treatment of various inflammation-associated diseases, with a special emphasis on its role in modulating immune cell signaling or non-immune cell signaling within the inflammatory microenvironment, and we highlight the latest advances in nano-delivery strategies for celastrol to treat diseases associated with inflammation.

CB2R agonist JWH-133 attenuates chronic inflammation by restraining M1 macrophage polarization via Nrf2/HO-1 pathway in diet-induced obese mice

AIMS

Cannabinoid receptor 2 (CB2R) is an important regulator of immunoinflammatory responses. Interestingly, studies have demonstrated that CB2R was expressed in metabolically active tissue, so we speculated that CB2R might have a crucial impact on energy balance. We thus examined the anti-inflammatory activities of CB2R and a CB2R agonist, JWH-133, in diet-induced obese in mice as well as in cultured macrophages.

MATERIALS AND METHODS

We evaluated the in vivo effect of JWH-133 on diet-induced adipose tissue inflammation. We also assessed the in vitro effects of JWH-133 on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages, with a focus on the nuclear factor E2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signaling pathway.

KEY FINDINGS

We found that JWH-133 reduced body weight gain, relieved glucose tolerance, and enhanced insulin sensitivity in a mouse model. It also down-regulated the expression of M1 macrophage biomarkers (tumor necrosis factor-α, interleukin (IL)-6, inducible nitric oxide synthase (iNOS), IL-1β, CC motif chemokine ligand 2, and C-X-C motif chemokine 10) in vivo and in vitro, but up-regulated levels of M2 macrophage biomarkers (IL-10 and arginase-1) in both mice and cultured macrophages. Furthermore, the underlying mechanisms were studied in an LPS-treated RAW264.7 cell line. We found a role for JWH-133 in controlling M1 macrophage polarization by activating the Nrf2/HO-1 pathway, while the effect of JWH-133 was diminished by a HO-1 inhibitor, Sn(IV) protoporphyrin IX dichloride.

SIGNIFICANCE

JWH-133 showed anti-obesity effects that ameliorated pro-inflammatory M1 macrophage polarization through the Nrf2/HO-1 pathway. Therefore, our results provide a new proof for the potential use of the CB2R agonist, JWH-133, in the treatment of obesity.