Berberine alleviates chlorpyrifos-induced nephrotoxicity in rats via modulation of Nrf2/HO-1 axis

Chlorpyrifos (CPS), an organophosphorus insecticide, is widely used for agricultural and non-agricultural purposes with hazardous health effects. Berberine (BBR) is a traditional Chinese medicine and a phytochemical with anti-inflammatory and anti-oxidative properties. The present study evaluated the effects of BBR against kidney damage induced by CPS and the underlying mechanisms. An initial study indicated that BBR 50 mg/kg was optimal under our experimental conditions. Then, 24 rats (6/group) were randomized into: control, BBR (50 mg/kg/day), CPS (10 mg/kg/day), and CPS + BBR. BBR was administration 1 h prior to CPS. Each treatment was delivered daily for a period of 28 consecutive days using a gastric gavage tube. Compared to CPS-alone treated rats, BBR effectively improved renal function by preventing the rise in serum urea, creatinine, and uric levels. The reno-protective effects of BBR were confirmed through a histological examination of kidney tissues. BBR restored oxidant-antioxidant balance in renal tissues mediated by Keap1/Nrf2/HO-1 axis modulation. In addition, BBR decreased nitric oxide (NO) and myeloperoxidase (MPO) activity. This was paralleled with the potent down-regulation of NF-κB. Furthermore, BBR exhibited anti-apoptotic activities supported by the upregulation of Bcl-2 and down-regulation of Bax and caspase-3 expression. In conclusion, our data suggest that BBR attenuates CPS-induced nephrotoxicity in rats by restoring oxidant-antioxidant balance and inhibiting inflammatory response and apoptosis in renal tissue. This is mediated, at least partly, by modulation of the Nrf2/HO-1 axis.

Effects of the CB1 receptor antagonists AM6545 and AM4113 on metabolic syndrome-induced prostatic hyperplasia in rats

Metabolic syndrome (MetS) is a combination of metabolic disorders that can predispose individuals to benign prostatic hyperplasia (BPH). The inhibition of the cannabinoid 1 (CB1) receptor has been used to treat metabolic disorders in animal models. This study reports the use of a peripherally restricted CB1 antagonist (AM6545) and a neutral CB1 antagonist (AM4113) to improve MetS-related BPH in rats. Animals were divided into three control groups to receive either a normal rodent diet, AM6545, or AM4113. MetS was induced in the fourth, fifth, and sixth groups using a concentrated fructose solution and high-salt diet delivered as food pellets for eight weeks. The fifth and sixth groups were further given AM6545 or AM4113 for additional four weeks. Body and prostate weights were measured and prostate sections were stained with hematoxylin eosin. Cyclin D1, markers of oxidative stress and inflammation, and levels of the endocannabinoids were recorded. BPH in rats with MetS was confirmed through increased prostate weight and index, as well as histopathology. Treatment with either AM6545 or AM4113 significantly decreased prostate weight, improved prostate histology, and reduced cyclin D1 expression compared with the MetS group. Groups treated with CB1 antagonists experienced reduced lipid peroxidation, recovered glutathione depletion, restored catalase activity, and had lower inflammatory markers interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α). MetS rats treated with either AM6545 or AM4113 showed reduced concentrations of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in the prostate compared with the MetS group. In conclusion, the CB1 antagonists AM6545 and AM4113 protect against MetS-induced BPH through their anti-proliferative, antioxidant, and anti-inflammatory effects.

Protective Effects of 2-Methoxyestradiol on Acute Isoproterenol-Induced Cardiac Injury in Rats

Myocardial injury (MI) is an important pathological driver of mortality worldwide., and arises as a result of imbalances between myocardial oxygen demand and supply. In MI, oxidative stress often leads to inflammatory changes and apoptosis. Current therapies for MI are known to cause various adverse effects. Consequently, the development of new therapeutic agents with a reduced adverse event profile is necessary. In this regard, 2-methoxyestradiol (2ME), the metabolic end-product of oestradiol, possesses anti-inflammatory and antioxidant properties. The aim of this research is to assess the impact of 2ME on cardiac injury caused by isoproterenol (ISO) in rats. Animals were separated into six groups; controls, and those receiving 2ME (1 mg/kg), ISO (85 mg/kg), ISO + 2ME (0.25 mg/kg), ISO + 2ME (0.5 mg/kg), and ISO + 2ME (1 mg/kg). 2ME significantly attenuated ISO-induced changes in electrocardiographic changes and the cardiac histological pattern. This compound also decreased lactate dehydrogenase activity, creatine kinase myocardial band and troponin levels. The ability of 2ME to act as an antioxidant was shown by a decrease in malondialdehyde concentration, and the restoration of glutathione levels and superoxide dismutase activity. Additionally, 2ME antagonized inflammation and cardiac cell apoptosis, a process determined to be mediated, at least partially, by suppression of Gal-3/TLR4/MyD88/NF-κB signaling pathway. 2ME offers protection against acute ISO-induced MI in rats and offers a novel therapeutic management option.

Allele frequency and genotype distribution of the opioid receptor μ-1 (OPRM1) A118G polymorphism in the Western Saudi population

The single nucleotide polymorphism (SNP) A118G (rs1799971) in the Mu Opioid Receptor 1 (OPRM1) gene is associated with significant variations in analgesic doses and adverse effects of opioids. The A118G OPRM1 allele distributions vary significantly between different populations worldwide. The study aimed to assess the allele frequency and genotype distribution of OPRM1 A118G SNP in Saudis. This cross-sectional study included 124 healthy Saudis (62 males and 62 females) visiting the King Abdulaziz University Hospital in Jeddah, Saudi Arabia. The Oragene®-DISCOVER (OGR-600) kits were used to collect saliva samples from the participants. Polymerase chain reaction-restriction fragment length polymorphism was utilized to assess the SNP. Among the tested population, 79.03% (95% C.I. 70.81-85.82) were homozygous wild-type A118A, 16.13% (95% C.I. 10.14-23.80) were heterozygous A118G, and 4.84% (95% C.I. 1.80-10.23) were homozygous mutant G118G. OPRM1 A118G polymorphism allele frequencies were 87% (95% C.I. 79.89-92.44) and 13% (95% C.I. 7.56-20.11) for the 118A and 118G alleles, respectively. A higher frequency of the OPRM1 118G allele was present in females, 21% (95% C.I. 11.66-33.17) compared to males, 5% (95% C.I. 1.01-13.50). Relative to other Asian countries, the Saudi population showed a low prevalence of the OPRM1 A118G polymorphism, with a higher frequency of the 118G allele in females. Our research will contribute to the existing knowledge on the prevalence of OPRM1 A118G polymorphism, which could be considered for the personalized prescribing of opioid analgesics.

Association of CYP2C9∗3 and CYP2C8∗3 Non-Functional Alleles with Ibuprofen-Induced Upper Gastrointestinal Toxicity in a Saudi Patient

Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID) widely used to alleviate pain and inflammation. Although it is generally considered safe, common adverse drug reactions of ibuprofen include stomach pain, nausea, and heartburn. It can also cause gastrointestinal (GI) bleeding, especially in individuals with a history of GI ulcers or bleeding disorders. Ibuprofen is predominantly metabolized by the cytochrome P450 (CYP) enzymes CYP2C9 and CYP2C8. Individuals carrying the CYP2C9∗3 or CYP2C8∗3 non-functional alleles have reduced enzyme activities resulting in elevated ibuprofen plasma concentrations and half-life. We presented a case of a 31-year-old Saudi female patient with a history of rheumatoid arthritis (RA) who had taken ibuprofen at 600 mg twice daily for eight weeks. The patient presented to the emergency department with symptoms including nausea, vomiting, severe abdominal pain, and black tarry stools. An emergency esophagogastroduodenoscopy was performed on the patient, which revealed a deep bleeding ulcer measuring 1 × 1 cm in the antrum of the stomach. Laboratory investigations indicated anemia (hemoglobin: 7.21 g/dL and hematocrit: 22.40 g/dl). The patient received intravenous proton pump inhibitors and a packed red blood cell transfusion. Genetic analysis revealed that the patient was a carrier of CYP2C9∗3 and CYP2C8∗3 variant alleles, indicating that the patient is a poor metabolizer for both enzymes. The patient's symptoms improved over the subsequent days, and she was discharged with instructions to avoid NSAIDs. This is the first reported Saudi patient homozygous for CYP2C9∗3 and CYP2C8∗3 variant alleles, which led to ibuprofen-induced upper GI toxicity. This case demonstrates the importance of contemplating CYP2C9 and CYP2C8 genetic variations when administrating NSAIDs like ibuprofen. Careful assessment of the risks and benefits of NSAID therapy in each patient and consideration of alternative pain management strategies must be conducted when appropriate.

The effect of virtual reality distraction on anxiety level during dental treatment among anxious pediatric patients: a randomized clinical trial

This study evaluated the effect of Virtual Reality Distraction (VRD) on dental anxiety among anxious children undergoing prophylactic dental treatment by utilizing both subjective (Venham Anxiety and Behavioral Rating Scale (VABRS)) and objective (heart rate (HR) and salivary cortisol level (SCL)) measures. This randomized controlled study included 36 (6- to 14-year-old) healthy and anxious children who needed prophylactic dental treatment and had a history of previous dental treatment. The eligible children's anxiety level was evaluated using a modified version of the Abeer Dental Anxiety Scale-Arabic version (M-ACDAS) and those who scored at least 14 or more out of 21 were included. Participants were randomly distributed to either the VRD or control group. In the VRD group, participants wore the VRD eyeglasses during prophylactic dental treatment. In the control group, subjects received their treatment while watching a video cartoon on a regular screen. The participants were videotaped during the treatment, and their HR was recorded at four time points. Also, a sample from each participant's saliva was collected twice, at the baseline and after the procedure. The mean M-ACDAS score at baseline in the VRD and the control groups was not statistically significant (p = 0.424). At the end of the treatment, the SCL was significantly lower in the VRD group (p < 0.001). Neither the VABRS (p = 0.171) nor the HR significantly differed between the VRD and control groups. Virtual reality distraction is a non-invasive method that has the potential to significantly reduce anxiety during prophylactic dental treatment among anxious children.

Lycopene attenuates chlorpyrifos-induced hepatotoxicity in rats via activation of Nrf2/HO-1 axis

Chlorpyrifos (CPF), is an organophosphate pesticide that is widely used for agricultural purposes. However, it has well-documented hepatotoxicity. Lycopene (LCP) is a plant-derived carotenoid with antioxidant and anti-inflammatory activities. The present work was designed to evaluate the potential hepatoprotective actions of LCP against CPF-induced hepatotoxicity in rats. Animals were assigned into five groups namely: Group I (Control), Group II (LCP), Group III (CPF), Group IV (CPF + LCP 5 mg/kg), and Group V (CPF + LCP 10 mg/kg). LCP offered protection as evidenced by inhibiting the rise in serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) induced by CPF. This was confirmed histologically as LCP-treated animals showed liver tissues with less proliferation of bile ducts and periductal fibrosis. LCP significantly prevented the rise in hepatic content of malondialdehyde (MDA), depletion of reduced glutathione (GSH), and exhaustion of glutathione-s-transferase (GST) and superoxide dismutase (SOD). Further, LCP significantly prevented hepatocyte death as it ameliorated the increase in Bax and the decrease in Bcl-2 expression induced by CPF in liver tissues as determined immunohistochemically. The observed protective effects of LCP were further confirmed by a significant enhancement in heme oxygenase-1 (HO-1) and NF-E2-related factor 2 (Nrf2) expression. In conclusion, LCP possesses protective effects against CPF-induced hepatotoxicity. These include antioxidation and activation of the Nrf2/HO-1 axis.

Parthenolide Phytosomes Attenuated Gentamicin-Induced Nephrotoxicity in Rats via Activation of Sirt-1, Nrf2, OH-1, and NQO1 Axis

Nephrotoxicity is a serious complication that limits the clinical use of gentamicin (GEN). Parthenolide (PTL) is a sesquiterpene lactone derived from feverfew with various therapeutic benefits. However, PTL possesses low oral bioavailability. This study aimed to evaluate the therapeutic protective effects of PTL-phytosomes against GEN-induced nephrotoxicity in rats. The PTL was prepared as phytosomes to improve the pharmacological properties with a particle size of 407.4 nm, and surface morphology showed oval particles with multiple edges. Rats were divided into six groups: control, nano-formulation plain vehicle, PTL-phytosomes (10 mg/kg), GEN (100 mg/kg), GEN + PTL-phytosomes (5 mg/kg), and GEN + PTL-phytosomes (10 mg/kg). The administration of PTL-phytosomes alleviated GEN-induced impairment in kidney functions and histopathological damage, and decreased kidney injury molecule-1 (KIM-1). The anti-oxidative effect of PTL-phytosomes was demonstrated by the reduced malondialdehyde (MDA) concentration and increased superoxide dismutase (SOD) and catalase (CAT) activities. Furthermore, PTL-phytosomes treatment significantly enhanced sirtuin 1 (Sirt-1), nuclear factor erythroid-2-related factor-2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), and heme oxygenase-1 (HO-1). Additionally, PTL-phytosomes treatment exhibited anti-inflammatory and anti-apoptotic properties in the kidney tissue. These findings suggest that PTL-phytosomes attenuate renal dysfunction and structural damage by reducing oxidative stress, inflammation, and apoptosis in the kidney.

Cannabinoid receptor 1 positive allosteric modulator (GAT229) attenuates cisplatin-induced neuropathic pain in mice

Chemotherapy-induced peripheral neuropathy (CIPN) is one of chemotherapies' most often documented side effects. Patients with CIPN experience spontaneous burning, numbness, tingling, and neuropathic pain in their feet and hands. Currently, there is no effective pharmacological treatment to prevent or treat CIPN. Activating the cannabinoid receptor type 1 (CB₁) by orthosteric agonists has shown promising results in alleviating the pain and neuroinflammation associated with CIPN. However, the use of CB₁ orthosteric agonists is linked to undesirable side effects. Unlike the CB₁ orthosteric agonists, CB₁ positive allosteric modulators (PAMs) don't produce any psychoactive effects, tolerance, or dependence. Previous studies have shown that CB₁ PAMs exhibit antinociceptive effects in inflammatory and neuropathic rodent models. This study aimed to investigate the potential benefits of the newly synthesized GAT229, a pure CB₁ PAM, in alleviating neuropathic pain and slowing the progression of CIPN. GAT229 was evaluated in a cisplatin-induced (CIS) mouse model of peripheral neuropathic pain (3 mg/kg/d, 28 d, i.p.). GAT229 attenuated and slowed the progression of thermal hyperalgesia and mechanical allodynia induced by CIS, as evaluated by the hotplate test and von Frey filament test. GAT229 reduced the expression of proinflammatory cytokines in the dorsal root ganglia (DRG) neurons. Furthermore, GAT229 attenuated nerve injuries by normalizing the brain-derived neurotrophic factor and the nerve growth factor mRNA expression levels in the DRG neurons. The CB₁ receptor antagonist/inverse agonist AM251 blocked GAT229-mediated beneficial effects. According to our data, we suggest that CB₁ PAMs might be beneficial in alleviating neuropathic pain and slowing the progression of CIPN.

Garcinone E Mitigates Oxidative Inflammatory Response and Protects against Experimental Autoimmune Hepatitis via Modulation of Nrf2/HO-1, NF-κB and TNF-α/JNK Axis

Garcinia mangostana L. (Clusiaceae), a popular tropical fruit for its juiciness and sweetness, is an opulent fountain of prenylated and oxygenated xanthones with a vast array of bio-activities. Garcinone E (GE), a xanthone derivative reported from G. mangostana, possesses cytotoxic and aromatase inhibitory activities. The present research endeavors to investigate the hepato-protection efficaciousness of GE on concanavalin-A (Con-A)-instigated hepatitis. Results showed that GE pretreating noticeably diminishes both the serum indices (transaminases, ALP, LDH, and γ-GT) and histopathological lesions of the liver. It counteracted neutrophil and CD4+ infiltration into the liver. GE furthered the Nrf2 genetic expression and its antioxidants' cascade, which resulted in amelioration of Con-A-caused oxidative stress (OS), lipid per-oxidative markers (4-HNE, MDA, PC) reduction, and intensified antioxidants (TAC, SOD, GSH) in the hepatic tissue. Additionally, GE prohibited NF-ĸB (nuclear factor kappa-B) activation and lessened the genetics and levels of downstream cytokines (IL1β and IL6). Moreover, the TNF-α/JNK axis was repressed in GE-treated mice, which was accompanied by attenuation of Con-A-induced apoptosis. These findings demonstrated the protective potential of GE in Con-A-induced hepatitis which may be associated with Nrf2/HO-1 signaling activation and OS suppression, as well as modulation of the NF-κB and TNF-α/JNK/apoptosis signaling pathway. These results suggest the potential use of GE as a novel hepato-protective agent against autoimmune hepatitis.

The Adverse Reactions of Pfizer BioNTech COVID-19 Vaccine Booster Dose are Mild and Similar to the Second Dose Responses: A Retrospective Cross-Sectional Study

Background

Like other vaccines, Pfizer BioNTech’s COVID-19 vaccine efficacy against SARS-CoV-2 virus infections begins to decline within a few months after the 2^nd dose. On August 12, 2021, the FDA allowed additional Pfizer BioNTch’s COVID-19 vaccine dose (3^rd or booster dose) for individuals with weakened immunity. This study aimed to evaluate the short-term adverse reactions (ADRs) of the 2^nd and the 3^rd doses of the Pfizer BioNTech COVID-19 vaccine.

Methods

Information for this study was collected by Google Form questionnaire (online survey). The results included responses from 442 people, the majority from Saudi Arabia.

Results

The most common local ADRs following the 3^rd dose were injection site pain, injection site hypersensitivity, and axillary lymph node swelling. The most common systemic ADRs were fatigue, muscle pain, bone pain, headache, and fever less than 38ºC. Less common systemic ADRs were shivering, fever more than 38ºC, nasal congestion and rhinorrhea, arrhythmia, cough, abdominal pain, chest tightness, nausea, diarrhea, vomiting, and tachypnea. Rare systemic ADRs were constipation, dizziness and vertigo, lack of concentration, sore throat, excessive hair loss, dysmenorrhea and heavy menstruation, and Bell’s palsy. Severe allergic reactions were reported by 2.6% of participants after the 2^nd dose, compared with none after the 3^rd dose. Nasal congestion and runny nose are more frequent after the 3^rd dose. The ADRs of the 2^nd and 3^rd doses were significantly more prevalent in females. 12% of participants reported ADRs lasting more than one week after the 3^rd dose compared to 5% after the 2^nd dose. People ≤ 60 years were more affected by the vaccine ADRs.

Conclusion

Most of the ADRs reported after the 3^rd vaccine dose were consistent with the Pfizer vaccine information sheet and similar to the 2^nd dose ADRs.

Assessment of commitment to healthy daily habits and diets, preventive measures, and beliefs about natural products utilization during COVID-19 pandemic in certain population in Egypt and Saudi Arabia

Objective

The purpose of this research is to assess the commitment of participants in Saudi Arabia and Egypt towards healthy daily habits, preventive measures, healthy food habits, and beliefs about natural products as an immunostimulants during COVID-19 pandemic.

Method

A cross-sectional questionnaire-based study was conducted in Saudi Arabia (mainly Riyadh and Jeddah) and Egypt (mainly Cairo). The questionnaire instrument was created based on an extensive literature review on the COVID-19 pandemic, including its spreading and transmission methods, preventive measures, healthy lifestyle, and diets that increase human immunity against viral infections and the use of natural products and drinks. The questionnaire was created by Microsoft 365® office forms, participants were invited through emails and other social media. The questionnaire includes a demographic section (gender, nationality, residency country, city, age, marital status, educational level, employment status, chronic disease history, under anxiety or stress, have a temper or irritable person, were infected/currently infected and in contact to COVID-19 patient) and (23) questions arranged under five domains; Domain I daily habits (4), Domain II keeping preventive measures (4), Domain III healthy eating habits (9), Domain IV for participants currently or previously infected, or in contact with a patient (4) Domain V for assessment of participants' beliefs towards the use of natural products to elevate immunity during COVID-19 pandemic (2), beside 4 choice questions (stimulant drinks, natural drinks, natural products, and zinc-rich food). SPSS® was used to analyze the results using Student' t-test, ANOVA, and Tukey's HSD tests.

Result

510 individuals with various demographic characteristics participated in the study. This study revealed that the participants belief in healthy foods, natural drinks (mainly ginger, lemon, and cinnamon), natural products (mainly honey, olive oil, and black seed), healthy habits, and preventive measures as sanitizers, social distance, and exercise. Only 13% of all participants were infected with COVID-19, although 31% of them were in contact with COVID -19 patients, about 93% were under stress, and 22% were with chronic diseases. Participants who are married, not in contact with patients and not previously infected by COVID-19 are more adhered to preventive measures while those previously or currently infected are more committed to healthy lifestyle and diet habits. Qualification level seems to make no significant difference in any domain. 78.6% of the participants beliefs in the benefits of utilizing natural products in preventing infection with corona virus or reducing the period of treatment in case of infection. About 95.7% of the infected persons had no need of hospitalization and about 50% are cured within two weeks of infection. The questionnaire revealed that Nescafe and black tea were the most used stimulant drinks among the participants, particularly the students and who were always under stress. Most of the participants agreed with the utilization of Zn-rich food, particularly Egyptians, which may help in boosting their immunity.

Conclusion

Natural products selected in the present study can be used in combination with the existing clinical standards of care that have the potential to serve as prophylactic agents in populations that are at risk to develop COVID-19 infection.

Piceatannol SNEDDS Attenuates Estradiol-Induced Endometrial Hyperplasia in Rats by Modulation of NF-κB and Nrf2/HO-1 Axes

Endometrial hyperplasia (EH) is the most common risk factor for endometrial malignancy in females. The pathogenesis of EH has been directly linked to uterine inflammation, which can result in abnormal cell division and decreased apoptosis. Piceatannol (PIC), a natural polyphenolic stilbene, is known to exert anti-inflammatory, antioxidant and anti-proliferative activities. The aim of the present study was to examine the potential preventive role of PIC in estradiol benzoate (EB)-induced EH in rats. A self-nanoemulsifying drug delivery system (SNEDDS) was prepared to improve the solubility of the PIC. Therefore, thirty female Wistar rats were divided into five groups: (1) control, (2) PIC SNEDDS (10 mg/kg), (3) EB (0.6 mg/kg), (4) EB + PIC SNEDDS (5 mg/kg) and (5) EB + PIC SNEDDS (10 mg/kg). The administration of PIC SNEDDS prevented EB-induced increases in uterine weights and histopathological changes. Additionally, it displayed pro-apoptotic and antioxidant activity in the endometrium. Immunohistochemical staining of uterine sections co-treated with PIC SNEDDS showed significantly decreased expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nuclear transcription factor-kappa B (NF-κB). This anti-inflammatory effect was further confirmed by a significant increase in Nrf2 and heme oxygenase-1 (HO-1) expression. These results indicate that SNEDDS nanoformulation of PIC possesses protective effects against experimentally induced EH.

Genetic polymorphism of the drug-metabolizing enzyme Cytochrome P4502E1 (CYP2E1) in a healthy Saudi population

Objectives

Cytochrome P450 2E1 (CYP2E1) is one of the major enzymes involved in the metabolism and detoxification of various drugs and xenobiotics. Polymorphisms in the CYP2E1 gene exhibit high inter-individual variations associated with alterations in CYP2E1 gene expression and enzyme function. This study aimed to determine the genotype distributions and allele frequencies of CYP2E1*1B, *5B, and *6 polymorphisms among Saudis in western Saudi Arabia.

Methods

In total, 140 healthy Saudis attending King Abdulaziz University Hospital between February and April 2021 were included in the study. CYP2E1 gene polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

The genotype frequencies of CYP2E1*1B A2A2, A2A1, and A1A1 were 54.29%, 40%, and 8%, respectively. The frequencies of CYP2E1*5B c1c1 and c1c2 genotypes were approximately 99.93% and 0.07%, respectively. The frequencies of the CYP2E1*6 DD, DC, and CC genotypes were 91.43%, 7.85%, and 0.72%, respectively. The genotype distributions for these polymorphisms were consistent with the expected distribution based on Hardy-Weinberg equilibrium. The allele frequencies were 74.29% A2 and 25.71% A1 for CYP2E1*1B, 99.64% c1 and 0.36% c2 for CYP2E1*5B, and 95.36% D and 4.65% C for CYP2E1*6.

Conclusion

The genotype distribution of CYP2E1*1B polymorphism was higher in the western Saudi population, whereas the CYP2E1*5B and *6 polymorphisms were lower than the global average. Knowledge of the prevalence of CYP2E1 polymorphisms among our population will provide a better understanding of whether individual patients might benefit from their medication or whether they might develop adverse effects.

Clinical and radiographic evaluation of triple antibiotic paste pulp therapy compared to Vitapex pulpectomy in non-vital primary molars

Objectives

This study compared and evaluated the clinical and radiographic efficacy of non‐instrumentation triple antibiotic paste pulp therapy and Vitapex pulpectomy in non‐vital primary molars.

Material and Methods

Healthy, 5–9 years old children with at least one non‐vital primary molar were included in the study. Molars were divided into two groups based on the subject's cooperation level. In the first group, molars received triple antibiotic paste, and a second group received Vitapex pulpectomy followed by a stainless‐steel crown. Triple antibiotic paste was freshly prepared and proportioned in equal parts by volume (metronidazole, minocycline, and ciprofloxacin = 1:1:1) before the scheduled treatment. A clinical and radiographic examination was performed by two trained and calibrated pediatric dentists at the pre‐operative baseline and the 6‐ and 12‐month follow‐up visits.

Results

A total of 28 molars received triple antibiotic paste pulp therapy and 20 received Vitapex pulpectomy. At the 6‐month follow‐up, the success rate among the molars in the triple antibiotic paste group was clinically (92.85%) and radiographically (85.71%) higher compared to the Vitapex group (91.67%, 62.50% respectively) with p = 0.89 and 0.55 respectively. At the 12‐month follow‐up, the molars in the triple antibiotic paste group showed lower clinical (95.45%) but higher radiographic success rate (72.73%) compared to the Vitapex group (100% and 62.50%) with (p = 0.85 and 0.47) respectively. None of the differences were statistically significant.

Conclusions

Both triple antibiotic paste and Vitapex can be clinically and radiographically effective in treating non‐vital primary molars.

Minor to Moderate Side Effects of Pfizer-BioNTech COVID-19 Vaccine Among Saudi Residents: A Retrospective Cross-Sectional Study

Background

The Pfizer-BioNTech COVID-19 vaccine has recently received emergency approval from the US FDA. The mRNA technology was used to manufacture the Pfizer vaccine; however, as a pioneering technology that has never been used in the manufacture of vaccines, many people have concerns about the vaccine’s side effects. Thus, the current study aimed to track the short-term side effects of the vaccine.

Methods

The information in this study was gathered by a Google Form-questionnaire (online survey). The results included the responses of 455 individuals, all of whom are Saudi Arabia inhabitants. Adverse effects of the vaccine were reported after the first and the second doses.

Results

The most common symptoms were injection site pain, headaches, flu-like symptoms, fever, and tiredness. Less common side effects were a fast heartbeat, whole body aches, difficulty breathing, joint pain, chills, and drowsiness. Rare side effects include Bell’s palsy and lymph nodes swelling and tenderness. Flu-like symptoms were more common among those under 60 years of age, while injection site pain was more frequent among recipients who were 60 years and older. The study revealed a significant increase in the number of females who suffered from the vaccine side effects compared to males. Difficulty of breathing was more reported among recipients who had been previously infected with the coronavirus compared to those who had not been previously infected.

Conclusion

Most of the side effects reported in this study were consistent with Pfizer’s fact sheet for recipients and caregivers. Further studies are required to determine the long-term side effects.

Activation of Sirtuin 1 by Ellagic Acid Ameliorates Cisplatin-Induced Apoptosis, Oxidative Stress and Nephrotoxicity

Background: Cisplatin (Cis) is a chemotherapeutic agent commonly applied in treating different cancers. However, acute renal injury remains a major side effect of Cis that limits its clinical use. Oxidative stress in renal tissues play a key role in Cis-induced toxicity. This research aimed to investigate the impact of ellagic acid (Ella) on Cis-induced apoptotic renal injury and the possible involvement of sirtuin 1 (SIRT1) and oxidative stress as a possible protective mechanism. Methods: Twenty-four Sprague Dawley rats were divided into four groups (n=6) and treated as follows. The control (Cont) group (0.9% saline), Ella group (10 mg/kg), Cis group (7.5 mg/kg), Ella + Cis group (10 mg/kg + 7.5 mg/kg). Ella was administered 7 days prior to Cis injection. Seventy-two hours later, the rats were sacrificed, and blood and kidney samples were collected.  Biochemical analyses were performed on serum and kidney homogenate. The histopathological and immunohistochemical analyses were performed on the formalin preserved kidneys. Results: Ella significantly decreased serum creatinine and urea levels compared to the Cis group. Furthermore, Ella protects the kidney cortex and medulla against most Cis-induced histopathological changes. Ella significantly decreased kidney contents of malondialdehyde (MDA). Moreover, Ella reversed the Cis-induced reduction of kidney antioxidants, including glutathione peroxidase, superoxide dismutase, and catalase. Ella decreased kidney protein expression of both cyclooxygenase-2 (COX-2) and Bax proteins while increased SIRT1 and Bcl2 expression. Conclusion: The results revealed a reduction in SIRT1 protein expression in rat renal medullary and cortical tissues following Cis treatment. However, Ella significantly enhanced SIRT1 expression, antioxidants levels, and reduced Cis-induced apoptosis, inflammation, and oxidative stress by increasing the ratio of Bax/Bcl-2 and reducing the expression of COX-2 and MDA, respectively. These findings provide additional evidence of the antioxidant and antiapoptotic effect of Ella in Cis-induced renal toxicity.

Knowledge, perception, and confidence of hospital pharmacists toward pharmacogenetics in Jeddah, Kingdom of Saudi Arabia

Background

Integrating pharmacogenetics (PGx) testing into clinical practice leads to personalized medicine, which improves treatments’ efficacy and safety. Successful implementation of such a service requires sufficient knowledge, perception, and self-confidence among healthcare providers, especially pharmacists.

Objectives

To evaluate governmental hospital pharmacists’ knowledge, perception, and self-confidence toward PGx testing in Jeddah, Kingdom of Saudi Arabia.

Method

This cross-sectional study was conducted using previously validated questionnaire. Pharmacists working in five randomly selected general governmental hospitals in Jeddah between August and October 2019 were interviewed. Comparative and descriptive analyses were used to analyze the data, and the significance level was at P-value < 0.05.

Results

A total of 119 pharmacists with a mean (±SD) age of 31.2 (±5.05) years were included with a response rate of 79.3%. The average total mean (±SD) score for PGx knowledge-based questions was low (2.4 ± 1.09 out of 5). Most of the participants, with a total mean score of (10.1 ± 1.6 out of 12), revealed a positive perception toward PGx testing and its implications. A moderate self-confidence score for utilizing PGx testing (4.3 ± 2.3 out of 8) was observed among the participants. Pharmacists who had completed postgraduate studies had a statistically higher mean knowledge score (P = 0.006) compared with pharmacists with undergraduate degrees.

Conclusion

Governmental hospital pharmacists have limited knowledge and understanding about PGx testing; however, the majority expressed a high level of awareness and agreed that PGx testing is a valuable tool for enhancing drug efficacy and safety. The study also highlighted the importance of improving pharmacists’ knowledge about PGx testing, which will help them in implementing such a valuable service into their clinical practice in Saudi hospitals.

Endothelin B receptor dysfunction mediates elevated myogenic tone in cerebral arteries from aged male Fischer 344 rats

The human brain requires adequate cerebral blood flow to meet the high demand for nutrients and to clear waste products. With age, there is a chronic reduction in cerebral blood flow in small resistance arteries that can eventually limit proper brain function. The endothelin system is a key mediator in the regulation of cerebral blood flow, but the contributions of its constituent receptors in the endothelial and vascular smooth muscle layers of cerebral arteries have not been well defined in the context of aging. We isolated posterior cerebral arteries from young and aged Fischer 344 rats, as well as ET_B receptor knock-out rats and mounted the vessels in plexiglass pressure myograph chambers to measure myogenic tone in response to increasing pressure and targeted pharmacological treatments. We used an ET_A receptor antagonist (BQ-123), an ET_B receptor antagonist (BQ-788), endothelin-1, an endothelin-1 synthesis inhibitor (phosphoramidon), and vessel denudation to dissect the roles of each receptor in aging vasculature. Aged rats exhibited a higher myogenic tone than young rats, and the tone was sensitive to the ET_A antagonist, BQ-123, but insensitive to the ET_B antagonist, BQ-788. By contrast, the tone in the vessels from young rats was raised by BQ-788 but unaffected by BQ-123. When the endothelial layer that is normally enriched with ET_B1 receptors was removed from young vessels, myogenic tone increased. However, denudation of the endothelial layer did not influence vessels from aged animals. This indicated that endothelial ET_B1 receptors were not functional in the vessels from aged rats. There was also an increase in ET_A receptor expression with age, whereas ET_B receptor expression remained constant between young and aged animals. These results demonstrate that in young vessels, ET_B1 receptors maintain a lower myogenic tone, but in aged vessels, a loss of ET_B receptor activity allows ET_A receptors in vascular smooth muscle cells to raise myogenic tone. Our findings have potentially important clinical implications for treatments to improve cerebral perfusion in older adults with diseases characterized by reduced cerebral blood flow.

Prevalence of methylenetetrahydrofolate reductase gene polymorphisms (C677T, and A1298C) among Saudi children receiving dental treatment

BACKGROUND

Methylenetetrahydrofolate reductase, the encoded by the MTHFR gene, plays a crucial role in converting the amino acid homocysteine to methionine. Two polymorphisms of the MTHFR gene, C677T and A1298C, reportedly reduce enzyme activity, resulting in hyperhomocysteinemia. Patients with C677T and A1298C polymorphisms may be at higher risk for developing abnormal hyperhomocysteinemia, which has been linked to catastrophic neurological including fatal outcomes.

OBJECTIVE

Determine the prevalence of the MTHFR gene variants C677T and A1298C among pediatric dental patients treated at King Abdulaziz University Hospital.

DESIGN

Cross-sectional.

SETTING

Clinics of pediatric dentistry department.

SUBJECTS AND METHODS

Healthy Saudi children 6-12 years old with no known allergies were screened for eligibility between May and December 2019. A single investigator collected saliva samples. The MTHFR C677T and A1298C polymorphisms were analyzed using polymerase chain reaction and restriction fragment length polymorphism.

MAIN OUTCOME MEASURE

The prevalence of MTHFR gene variants (C677T and A1298C) among the subjects.

SAMPLE SIZE

138.

RESULTS

MTHFR C677T polymorphism was present in 36.2% of the sample and 90.0% of children carrying this allele were heterozygotes. MTHFR A1298C polymorphism was present in 91.3% of the sample and 77.0% of the children carrying this allele were heterozygotes. No linkage disequilibrium between MTHFR C677T and MTHFR A1298C was observed within this sample.

CONCLUSIONS

Our study found a high frequency of the MTHFR A1298C genotype, which was substantially more abundant than expected based on a Hardy-Weinberg distribution. Therefore, caution is advised in using N2O in Saudi children as the increased prevalence of this MTHFR allele may increase the incidence of serious adverse effects among these children.

LIMITATIONS

Further studies are recommended with a larger sample size from randomly selected hospitals from different regions of Saudi Arabia.

CONFLICT OF INTEREST

None.

Heteromer formation between cannabinoid type 1 and dopamine type 2 receptors is altered by combination cannabinoid and antipsychotic treatments

The cannabinoid type 1 (CB₁ ) receptor and the dopamine type 2 (D₂ ) receptor are co-localized on medium spiny neuron terminals in the globus pallidus where they modulate neural circuits involved in voluntary movement. Physical interactions between the two receptors have been shown to alter receptor signaling in cell culture. The objectives of the current study were to identify the presence of CB₁ /D₂ heteromers in the globus pallidus of C57BL/6J male mice, define how CB₁ /D₂ heteromer levels are altered following treatment with cannabinoids and/or antipsychotics, and determine if fluctuating levels of CB₁ /D₂ heteromers have functional consequences. Using in situ proximity ligation assays, we observed CB₁ /D₂ heteromers in the globus pallidus of C57BL/6J mice. The abundance of the heteromers increased following treatment with the nonselective cannabinoid receptor agonist, CP55,940. In contrast, treatment with the typical antipsychotic haloperidol reduced the number of CB₁ /D₂ heteromers, whereas the atypical antipsychotic olanzapine treatment had no effect. Co-treatment with CP55,940 and haloperidol had similar effects to haloperidol alone, whereas co-treatment with CP55,940 and olanzapine had similar effects to CP55,940. The observed changes were found to have functional consequences as the differential effects of haloperidol and olanzapine also applied to γ-aminobutyric acid release in STHdh^Q7/Q7 cells and motor function in C57BL/6J male mice. This work highlights the clinical relevance of co-exposure to cannabinoids and different antipsychotics over acute and prolonged time periods.

Endothelin receptor heteromerization inhibits β-arrestin function in HEK293 cells

The endothelin receptor A (ETA) and endothelin receptor B (ETB) are G protein-coupled receptors that are co-expressed in vascular smooth muscle cells. Endothelin-1 (ET-1) activates endothelin receptors to cause microvascular vasoconstriction. Previous studies have shown that heteromerization between ETA and ETB prolongs Ca²⁺ transients, leading to prolongation of Gα_q-dependent signaling and sustained vasoconstriction. We hypothesized that these effects are in part mediated by the resistance of ETA/ETB heteromers to β-arrestin recruitment and subsequent desensitization. Using bioluminescence resonance energy transfer 2 (BRET²), we found that ETB has a relatively equal affinity to form either homomers or heteromers with ETA when co-expressed in the human embryonic kidney 293 (HEK293) cells. When co-expressed, activation of ETA and ETB by ET-1 caused a heteromer-specific reduction and delay in β-arrestin-2 recruitment with a corresponding reduction and delay in ET-1-induced ETA/ETB co-internalization. Furthermore, the co-expression of ETA and ETB inhibited ET-1-induced β-arrestin-1-dependent extracellular signal-regulated kinase (ERK) phosphorylation while prolonging ET-1-induced Gα_q-dependent ERK phosphorylation. ETA/ETB heteromerization mediates the long-lasting vasoconstrictor response to ET-1 by the prolongation of Gα_q-dependent signaling and inhibition of β-arrestin function.

Neurodevelopmental and genetic determinants of exposure to adversity among youth at risk for mental illness

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and lower cognitive ability have been linked with increased likelihood of exposure to adversity. We hypothesized that these associations may be partly due to genetic factors.

METHODS

We calculated polygenic scores for ADHD and intelligence and assessed psychopathology and general cognitive ability in a sample of 297 youth aged 5-27 years enriched for offspring of parents with mood and psychotic disorders. We calculated an adversity score as a mean of 10 indicators, including socio-economic disadvantage, childhood maltreatment and bullying. We tested the effects of polygenic scores, externalizing symptoms and IQ on adversity scores using mixed-effects linear regression.

RESULTS

Externalizing symptoms and general cognitive ability showed expected positive and negative relationships with adversity, respectively. Polygenic scores for intelligence were unrelated to adversity, but polygenic scores for ADHD were associated with adversity (β = 0.23, 95% CI 0.13 to 0.34, p < .0001). ADHD polygenic scores uniquely explained 4.0% of variance in adversity score. The relationship between polygenic scores for ADHD and adversity was independently significant among individuals with (β = 0.49, 95% CI 0.25 to 0.75, p < .0001) and without (β = 0.14, 95% CI 0.02 to 0.26, p = .022) ADHD.

CONCLUSIONS

A genetic score indexing liability to ADHD was associated with exposure to adversity in early life. Previously observed associations between externalizing symptoms, lower cognitive ability and adversity may be partially attributed to genetic liability to ADHD.

Positive allosteric modulation of the type 1 cannabinoid receptor reduces the signs and symptoms of Huntington's disease in the R6/2 mouse model

Huntington's disease (HD) is an inherited progressive neurodegenerative disease characterized by motor, cognitive, and behavioural changes. One of the earliest changes to occur in HD is a reduction in cannabinoid 1 receptor (CB₁) levels in the striatum, which is strongly correlated with HD pathogenesis. CB₁ positive allosteric modulators (PAM) enhance receptor affinity for, and efficacy of activation by, orthosteric ligands, including the endocannabinoids anandamide and 2-arachidonoylglycerol. The goal of this study was to determine whether the recently characterized CB₁ allosteric modulators GAT211 (racemic), GAT228 (R-enantiomer), and GAT229 (S-enantiomer), affected the signs and symptoms of HD. GAT211, GAT228, and GAT229 were evaluated in normal and HD cell models, and in a transgenic mouse model of HD (7-week-old male R6/2 mice, 10 mg/kg/d, 21 d, i.p.). GAT229 was a CB₁ PAM that improved cell viability in HD cells and improved motor coordination, delayed symptom onset, and normalized gene expression in R6/2 HD mice. GAT228 was an allosteric agonist that did not enhance endocannabinoid signaling or change symptom progression in R6/2 mice. GAT211 displayed intermediate effects between its enantiomers. The compounds used here are not drugs, but probe compounds used to determine the potential utility of CB₁ PAMs in HD. Changes in gene expression, and not protein, were quantified in R6/2 HD mice because HD pathogenesis is associated with dysregulation of mRNA levels. The data presented here provide the first proof of principle for the use of CB₁ PAMs to treat the signs and symptoms of HD.

Combining SRET2 and BiFC to Study GPCR Heteromerization and Protein-Protein Interactions

G protein-coupled receptors (GPCRs) are the target for many drugs. Evidence continues to accumulate demonstrating that multiple receptors form homo- and heteromeric complexes, which in turn dynamically couple with G proteins, and other interacting proteins. Here, we describe a method to simultaneously determine the identity of up to four distinct constituents of GPCR complexes using a combination of sequential bioluminescence resonance energy transfer 2-fluorescence resonance energy transfer (SRET²) with bimolecular fluorescence complementation (BiFC). The method is amenable to moderate throughput screening of changes in response to ligands and time-course analysis of protein-protein oligomerization.

Methods to Quantify Cell Signaling and GPCR Receptor Ligand Bias: Characterization of Drugs that Target the Endocannabinoid Receptors in Huntington's Disease

G protein-coupled receptors (GPCRs) interact with multiple intracellular effector proteins such that different ligands may preferentially activate one signal pathway over others, a phenomenon known as signaling bias. Signaling bias can be quantified to optimize drug selection for preclinical research. Here, we describe moderate-throughput methods to quantify signaling bias of known and novel compounds. In the example provided, we describe a method to define cannabinoid-signaling bias in a cell culture model of Huntington's disease (HD). Decreasing type 1 cannabinoid receptor (CB₁) levels is correlated with chorea and cognitive deficits in HD. There is evidence that elevating CB₁ levels and/or signaling may be beneficial for HD patients while decreasing CB₁ levels and/or signaling may be detrimental. Recent studies have found that Gα_i/o-biased CB₁ agonists activate extracellular signal-regulated kinase (ERK), increase CB₁ protein levels, and improve viability of cells expressing mutant huntingtin. In contrast, CB₁ agonists that are β-arrestin1-biased were found to reduce CB₁ protein levels and cell viability. Measuring agonist bias of known and novel CB₁ agonists will provide important data that predict CB₁-specific agonists that might be beneficial in animal models of HD and, following animal testing, in HD patients. This method can also be applied to study signaling bias for other GPCRs.

Cannabinoid receptor ligand bias: implications in the central nervous system

The G protein-coupled cannabinoid receptors CB₁, CB₂, GPR18, and GPR55 regulate neurotransmission, pain, and inflammation and have been intensively investigated as potential drug targets. Each of these GPCRs is coupled to multiple effector proteins mediating divergent cellular signals. The ligand bias of cannabinoid-targeted compounds is only beginning to be quantified. Research into cannabinoid bias is now revealing correlations between bias in cell culture and functional outcomes in vivo. We present an example study of cannabinoid bias in the context of Huntington disease. In future, an understanding of cannabinoid receptor structure and quantification of ligand bias will optimize drug selection matched to patient population and disease.

Biased Type 1 Cannabinoid Receptor Signaling Influences Neuronal Viability in a Cell Culture Model of Huntington Disease

Huntington disease (HD) is an inherited, autosomal dominant, neurodegenerative disorder with limited treatment options. Prior to motor symptom onset or neuronal cell loss in HD, levels of the type 1 cannabinoid receptor (CB1) decrease in the basal ganglia. Decreasing CB1 levels are strongly correlated with chorea and cognitive deficit. CB1 agonists are functionally selective (biased) for divergent signaling pathways. In this study, six cannabinoids were tested for signaling bias in in vitro models of medium spiny projection neurons expressing wild-type (STHdh(Q7/Q7)) or mutant huntingtin protein (STHdh(Q111/Q111)). Signaling bias was assessed using the Black and Leff operational model. Relative activity [ΔlogR (τ/KA)] and system bias (ΔΔlogR) were calculated relative to the reference compound WIN55,212-2 for Gαi/o, Gαs, Gαq, Gβγ, and β-arrestin1 signaling following treatment with 2-arachidonoylglycerol (2-AG), anandamide (AEA), CP55,940, Δ(9)-tetrahydrocannabinol (THC), cannabidiol (CBD), and THC+CBD (1:1), and compared between wild-type and HD cells. The Emax of Gαi/o-dependent extracellular signal-regulated kinase (ERK) signaling was 50% lower in HD cells compared with wild-type cells. 2-AG and AEA displayed Gαi/o/Gβγ bias and normalized CB1 protein levels and improved cell viability, whereas CP55,940 and THC displayed β-arrestin1 bias and reduced CB1 protein levels and cell viability in HD cells. CBD was not a CB1 agonist but inhibited THC-dependent signaling (THC+CBD). Therefore, enhancing Gαi/o-biased endocannabinoid signaling may be therapeutically beneficial in HD. In contrast, cannabinoids that are β-arrestin-biased--such as THC found at high levels in modern varieties of marijuana--may be detrimental to CB1 signaling, particularly in HD where CB1 levels are already reduced.

Cannabidiol is a negative allosteric modulator of the cannabinoid CB1 receptor

BACKGROUND AND PURPOSE

Cannabidiol has been reported to act as an antagonist at cannabinoid CB1 receptors. We hypothesized that cannabidiol would inhibit cannabinoid agonist activity through negative allosteric modulation of CB1 receptors.

EXPERIMENTAL APPROACH

Internalization of CB1 receptors, arrestin2 recruitment, and PLCβ3 and ERK1/2 phosphorylation, were quantified in HEK 293A cells heterologously expressing CB1 receptors and in the STHdh(Q7/Q7) cell model of striatal neurons endogenously expressing CB1 receptors. Cells were treated with 2-arachidonylglycerol or Δ(9)-tetrahydrocannabinol alone and in combination with different concentrations of cannabidiol.

KEY RESULTS

Cannabidiol reduced the efficacy and potency of 2-arachidonylglycerol and Δ(9)-tetrahydrocannabinol on PLCβ3- and ERK1/2-dependent signalling in cells heterologously (HEK 293A) or endogenously (STHdh(Q7/Q7)) expressing CB1 receptors. By reducing arrestin2 recruitment to CB1 receptors, cannabidiol treatment prevented internalization of these receptors. The allosteric activity of cannabidiol depended upon polar residues being present at positions 98 and 107 in the extracellular amino terminus of the CB1 receptor.

CONCLUSIONS AND IMPLICATIONS

Cannabidiol behaved as a non-competitive negative allosteric modulator of CB1 receptors. Allosteric modulation, in conjunction with effects not mediated by CB1 receptors, may explain the in vivo effects of cannabidiol. Allosteric modulators of CB1 receptors have the potential to treat CNS and peripheral disorders while avoiding the adverse effects associated with orthosteric agonism or antagonism of these receptors.

Components of the endocannabinoid and dopamine systems are dysregulated in Huntington's disease: analysis of publicly available microarray datasets

The endocannabinoid system (ECS) and the dopaminergic system (DAS) are two major regulators of basal ganglia function. During Huntington's disease (HD) pathogenesis, the expression of genes in both the ECS and DAS is dysregulated. The purpose of this study was to determine the changes that were consistently observed in the ECS and DAS during HD progression in the central nervous system (CNS) and in the periphery in different models of HD and human HD tissue. To do this, we conducted a meta-analysis of differential gene expression in the ECS and DAS using publicly available microarray data. The consolidated data were summarized as observed changes in gene expression (OCGE) using a weighted sum for each gene. In addition, consolidated data were compared to previously published studies that were not available in the gene expression omnibus (GEO) database. The resulting data confirm gene expression changes observed using different approaches and provide novel insights into the consistency between changes observed in human tissue and various models, as well as disease stage- and tissue-specific transcriptional dysregulation in HD. The major implication of the systems-wide data presented here is that therapeutic strategies targeting the ECS or DAS must consider the dynamic changes in gene expression over time and in different body areas, which occur during HD progression and the interconnectedness of the two systems.

Type 1 cannabinoid receptor ligands display functional selectivity in a cell culture model of striatal medium spiny projection neurons

Modulation of type 1 cannabinoid receptor (CB1) activity has been touted as a potential means of treating addiction, anxiety, depression, and neurodegeneration. Different agonists of CB1 are known to evoke varied responses in vivo. Functional selectivity is the ligand-specific activation of certain signal transduction pathways at a receptor that can signal through multiple pathways. To understand cannabinoid-specific functional selectivity, different groups have examined the effect of individual cannabinoids on various signaling pathways in heterologous expression systems. In the current study, we compared the functional selectivity of six cannabinoids, including two endocannabinoids (2-arachidonyl glycerol (2-AG) and anandamide (AEA)), two synthetic cannabinoids (WIN55,212-2 and CP55,940), and two phytocannabinoids (cannabidiol (CBD) and Δ(9)-tetrahydrocannabinol (THC)) on arrestin2-, Gα(i/o)-, Gβγ-, Gα(s)-, and Gα(q)-mediated intracellular signaling in the mouse STHdh(Q7/Q7) cell culture model of striatal medium spiny projection neurons that endogenously express CB1. In this system, 2-AG, THC, and CP55,940 were more potent mediators of arrestin2 recruitment than other cannabinoids tested. 2-AG, AEA, and WIN55,212-2, enhanced Gα(i/o) and Gβγ signaling, with 2-AG and AEA treatment leading to increased total CB1 levels. 2-AG, AEA, THC, and WIN55,212-2 also activated Gα(q)-dependent pathways. CP55,940 and CBD both signaled through Gα(s). CP55,940, but not CBD, activated downstream Gα(s) pathways via CB1 targets. THC and CP55,940 promoted CB1 internalization and decreased CB1 protein levels over an 18-h period. These data demonstrate that individual cannabinoids display functional selectivity at CB1 leading to activation of distinct signaling pathways. To effectively match cannabinoids with therapeutic goals, these compounds must be screened for their signaling bias.

Co-expression of the human cannabinoid receptor coding region splice variants (hCB₁) affects the function of hCB₁ receptor complexes

The human type 1 cannabinoid (hCB1) receptor is expressed at high levels in the central nervous system. mRNA variants of the coding region of this receptor, human cannabinoid hCB1a and hCB1b receptors, have been identified, their biological function remains unclear. The present study demonstrated that the three human cannabinoid hCB1 coding region variants are expressed in the human and monkey (Macaca fascicularis) brain. Western blot analyses of homogenates from different regions of the monkey brain demonstrated that proteins with the expected molecular weights of the cannabinoid CB1, CB1a and CB1b receptors were co-expressed throughout the brain. Given the co-localization of these receptors, we hypothesized that physical interactions between the three splice variants may affect cannabinoid pharmacology. The human cannabinoid hCB1, hCB1a, and hCB1b receptors formed homodimers and heterodimers, as determined by BRET in transiently transfected HEK 293A cells. We found that the co-expression of the human cannabinoid hCB1 and each of the splice variants increased cell surface expression of the human cannabinoid hCB1 receptor and increased Gi/o-dependent ERK phosphorylation in response to cannabinoid agonists. Therefore, the human cannabinoid hCB1 coding region splice variants play an important physiological role in the activity of the endocannabinoid system.