Activation of 5-HT6 Receptors in the Ventrolateral Orbital Cortex Produces Anti-Anxiodepressive Effects in a Rat Model of Neuropathic Pain.

The comorbidity of anxiety and depression frequently occurs in patients with neuropathic pain. The ventrolateral orbital cortex (VLO) plays a critical role in mediating neuropathic pain and anxiodepression in rodents. Previous studies suggested that 5-HT6 receptors in the VLO are involved in neuropathic pain. Strong evidence supports a close link between 5-HT6 receptors and affective disorders such as depression and anxiety disorders. However, it remains unclear whether the 5-HT6 receptors in the VLO are involved in neuropathic pain-induced anxiodepression. Using a rat neuropathic pain model of spared nerve injury (SNI), we demonstrated that rats exhibited significant anxiodepression-like behaviors and the expression of VLO 5-HT6 receptors obviously decreased four weeks after SNI surgery. Microinjection of the 5-HT6 receptor agonist EMD-386088 into the VLO or overexpression of VLO 5-HT6 receptors alleviated anxiodepression-like behaviors. These effects were blocked by pre-microinjection of a selective 5-HT6 receptor antagonist (SB-258585) or inhibitors of AC (SQ-22536), PKA (H89), and MEK1/2 (U0126) respectively. Meanwhile, the expression of p-ERK, p-CREB, and BDNF in the VLO decreased four weeks after SNI surgery. Furthermore, administration of EMD-386088 upregulated the expression of BDNF, p-ERK, and p-CREB in the VLO of SNI rats, which were reversed by pre-injection of SB-258585. These findings suggest that activating 5-HT6 receptors in the VLO has anti-anxiodepressive effects in rats with neuropathic pain via activating AC-cAMP-PKA-MERK-CREB-BDNF signaling pathway. Accordingly, 5-HT6 receptor in the VLO could be a potential target for the treatment of the comorbidity of neuropathic pain and anxiodepression.

Activation of 5-HT5A receptor in the ventrolateral orbital cortex produces antinociceptive effects in rat models of neuropathic and inflammatory pain.

The ventrolateral orbital cortex (VLO) is identified as an integral component of the endogenous analgesic system comprising a spinal cord - thalamic nucleus submedius - VLO - periaqueductal gray (PAG) - spinal cord loop. The present study investigates the effects of 5-HT5A receptor activation in the VLO on allodynia induced by spared nerve injury and formalin-evoked flinching behavior and spinal c-Fos expression in male SD rats, and further examines whether GABAergic modulation is involved in the effects evoked by VLO 5-HT5A receptor activation. We found an upregulation of 5-HT5A receptor expression in the VLO during neuropathic and inflammatory pain states. Microinjection of the non-selective 5-HT5A receptor agonist 5-CT into the VLO dose dependently alleviated allodynia, and flinching behavior and spinal c-Fos expression, which were blocked by the selective 5-HT5A receptor antagonist SB-699551. Moreover, application of the GABAA receptor antagonist bicuculline in the VLO augmented the analgesic effects induced by 5-CT in neuropathic and inflammatory pain states, whereas the GABAA receptor agonist muscimol attenuated these analgesic effects. Additionally, the 5-HT5A receptors were found to be colocalized with GABAergic neurons in the VLO. These results provide new evidence for the involvement of central 5-HT5A receptors in the VLO in modulation of neuropathic and inflammatory pain and support the hypothesis that activation of 5-HT5A receptors may inhibit the inhibitory effect of GABAergic interneurons on output neurons projecting to the PAG (GABAergic disinhibitory mechanisms), consequently activating the brainstem descending inhibitory system that depresses nociceptive transmission at the spinal cord level.

Attenuating effects of Azanza garckeana fractions on glycemo-impaired-associated dyslipidemia, hepatopathy, and nephropathy.

OBJECTIVES: The use of medicinal plants for diabetes treatment is increasing owing to their effectiveness and safety compared to synthetic drugs. Thus, the ameliorative effects of Azanza garckeana (F. Hoffm.) fractions in diabetes-induced dyslipidemia, hepatopathy, and nephropathy in rats were evaluated in this study. METHODS: Rats with alloxan (120 mg/kg body weight (BW))-induced diabetes were randomized into different groups (n=5) and treated with the crude methanolic extract, and fractions (n-hexane, ethyl acetate, and aqueous fractions) of A. garckeana each at 100, 200, and 400 mg/kg BW. Glibenclamide (5 mg/kg BW) was used as a reference drug, and all treatments were administered orally daily for 6 weeks. RESULTS: Our data revealed that treatment with the crude extract caused a dose-dependent hypoglycemic effect of 61.32±3.45%, 76.05±3.05%, and 78.59±5.90% at 100, 200, and 400 mg/kg BW, respectively and improved the BW of the animals. The extract also ameliorated the elevated cholesterol, triglyceride, low-density lipoprotein cholesterol, and increased serum levels of high-density lipoprotein cholesterol compared with untreated control animals. The extract also reversed serum biochemical alterations in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine, total and direct bilirubin, urea, and uric acid that were observed in untreated diabetic rats. Interestingly, the A. garckeana fraction also exhibited significant protection against diabetes-induced dyslipidemia, hepatopathy, and nephropathy in rats, with the ethyl acetate fraction exhibiting a remarkable protective effect. The LC-MS characterisation of the active fraction identified the presence of various phenolic and flavonoid compounds that could be responsible for the bioactivity of the fraction. CONCLUSION: Collectively, this study suggests the potential application of A. garckeana for effective treatment of diabetic nephropathy, with the ethyl acetate fraction of this plant representing a reserve of potential candidates for developing new drugs.

Luteolin-Rich Extract of Thespesia garckeana F. Hoffm. (Snot Apple) Contains Potential Drug-Like Candidates and Modulates Glycemic and Oxidoinflammatory Aberrations in Experimental Animals.

The present study evaluated the polyphenolic contents and hypoglycemic, antioxidant, and anti-inflammatory effects of the diethyl ether fraction of Thespesia garckeana using various in vitro and in vivo models. Total phenol and flavonoid contents of the extract were 613.65 ± 2.38 and 152.83 ± 1.56 mg/100 g dry weight, respectively. The extract exhibited in vitro antioxidant activities against DPPH, FRAP, LPO, and ABTS with respective half-maximal inhibitory concentration (IC50) values of 30.91 ± 0.23, 16.81 ± 0.51, 41.29 ± 1.82, and 42.39 ± 2.24 µg/mL. In vitro anti-inflammatory studies using membrane stabilization, protein denaturation, and proteinase activities revealed the effectiveness of the extract with respective IC50 values of 54.45 ± 2.89, 93.62 ± 3.04, and 56.60 ± 2.34 µg/mL, while in vitro hypoglycemic analysis of the extract revealed inhibition of α-amylase (IC5064.59 ± 3.29 µg/mL) and enhancement of glucose uptake by yeast cells. Interestingly, the extract demonstrated in vivo hypoglycemic and anti-inflammatory effects in streptozotocin- (STZ-) induced diabetic and xylene-induced ear swelling models, respectively. In addition, the extract improved insulin secretion, attenuated pancreatic tissue distortion and oxidative stress, and increased the activities of superoxide dismutase (SOD), catalase, and reduced glutathione (GSH), while reducing the concentration of LPO in the diabetic rats. A high-performance liquid chromatography (HPLC) analysis identified the presence of catechin (6.81e - 1 ppm), rutin (8.46 e - 1 ppm), myricetin, apigenin (4.019 e - 1 ppm), and luteolin (15.09 ppm) with respective retention times (RTs) of 13.64, 24.269, 27.781, 29.58, and 32.23 min, and these were subjected to a pharmacoinformatics analysis, which revealed their drug-likeness and good pharmacokinetic properties. A docking analysis hinted at the potential of luteolin, the most abundant compound in the extract, for targeting glucose-metabolizing enzymes. Thus, the present study provides preclinical insights into the bioactive constituents of T. garckeana, its antioxidant and anti-inflammatory effects, and its potential for the treatment of diabetes.

Biochemical and tissue physiopathological evaluation of the preclinical efficacy of Solanum torvum Swartz leaves for treating oxidative impairment in rats administered a ß-cell-toxicant (STZ).

The current study evaluated the protective role of Solanum torvum Swartz against diabetes-induced oxidative stress and tissue impairment in streptozotocin (STZ)-intoxicated rats. Rats with STZ (40 mg/kg intraperitoneally (i.p.))-induced diabetes were divided into five groups (n = 5) and treated with (i) normal saline, (ii) 150 mg/kg body weight (BW) of the ethanol extract of S. torvum leaf (EESTL), (ii) 300 mg/kg BW EESTL, (iv) 100 mg/kg BW metformin, and (v) 50 m/kg BW metformin + 100 mg/kg BW EESTL orally for 21 days. Our results revealed that the EESTL displayed dose-dependent ferric-reducing antioxidant power (FRAP) activity, scavenged DPPH radicals (IC50) = 13.52 ± 0.45 µg/mL), and inhibited lipid peroxidation in an in vitro models. In addition, the EESTL demonstrated dose-dependent inhibitory activity against α-amylase (IC50 =138.46 ± 3.97 µg/mL) and promoted glucose uptake across plasma membranes of yeast cells in a manner comparable to that of metformin. Interestingly, the extract demonstrated in vivo blood glucose normalization effects with concomitant increased activities of antioxidant parameters (superoxide dismutase (SOD), catalase, and reduced glutathione (GSH)) while decreasing malondialdehyde (MDA) levels when compared to untreated rats. Similarly, serum biochemical alterations, and tissues (liver, kidney, and pancreases) histopathological aberrations in untreated rats with STZ-induced diabetes were attenuated by treatment with the EESTL. Biometabolite characterization of the extract identified gallic acid (45.81 ppm), catechin (1.18 ppm), p-coumaric acid (1.43e-1 ppm), DL-proline 5-oxo-methyl ester (9.16 %, retention time (RT): 8.57 min), salicylic acid (3.26% and 7.61 min), and butylated hydroxytoluene (4.75%, RT: 10.18 min) as the major polyphenolic compounds in the plant extract. In conclusion, our study provides preclinical evidence of the antioxidant properties and oxidative stress-preventing role of S. torvum in STZ-dosed diabetic rats. Taken together, the EESTL represents a reserve of bioactive metabolites for managing diabetes and associated complications.

Preclinical anti-inflammatory and antioxidant effects of Azanza garckeana in STZ-induced glycemic-impaired rats, and pharmacoinformatics of it major phytoconstituents.

The quest for novel anti-diabetic medication from medicinal plants is very important since they contain bioactive phytochemicals that offer better activity and safety compared to conventional therapy. In the present study, in vitro, in vivo and in silico approaches were explored to evaluate the anti-inflammatory, antioxidants, and hypoglycemic activities of the crude methanol extract of Azanza garckeana pulp. Our in vitro analysis revealed that the extract contains total phenols (260.80 ±â€¯2.23 mg/100 g) and total flavonoids (10.28 ±â€¯1.29 mg/100 g) contents, and demonstrated dose-dependent in vitro antioxidants activities in; DPPH (IC50 =141.30 ±â€¯1.64 µg/mL), FRAP (IC50 =155.07 ±â€¯1.03 µg/mL), LPO (IC50 =184.96 ±â€¯2.01 µg/mL), and ABTS (IC50 =162.56 ±â€¯1.14 µg/mL) assays; anti-inflammatory activities in: membrane stabilization (IC50 =141.34 ±â€¯0.46 µg/mL), protein denaturation (IC50 =203.61 ±â€¯2.35 µg/mL) and proteinase activities (IC50=f 171.35 ±â€¯1.56 µg/mL) assays; and hypoglycemic activities in: α- amylase (IC50 277.85 ±â€¯2.51 µg/mL), and glucose uptake by yeast cells assays. In vivo analysis revealed that the extract exhibited dose-dependent anti-inflammatory, hypoglycemic activities and improved the weight gain in STZ-induced diabetic rats. In addition, the extract attenuated oxidative stress and increased the activities of SOD, catalase, GSH while depleting the level of LPO in STZ induced diabetic rats. Consequently, the liquid chromatography mass spectrometry (LC-MS) characterization of A. garckeana pulp, revealed the presence of 2-Hexadecen-1-ol,3,7,11,15-tetramethyl-,(2E,7 R,11 R)-, nonyl flavanone, testolactone and 6-(Benzyloxy)- 4,4-Dimethyl-2-Chromanone. These compounds were subjected to pharmacoinformatics analysis among which testolactone and 6-(Benzyloxy)- 4,4-Dimethyl-2-Chromanone demonstrated the best drug-likeness, pharmacokinetics, and also exhibited potential hypoglycemic and anti-inflammatory properties. Altogether, the present study provides preclinical evidence of the antioxidant, anti-inflammatory and antidiabetic activities of A. garckeana extract suggesting its potential applications for the development of alternative therapy for diabetes and its associated inflammatory condition.

Temozolomide-Acquired Resistance Is Associated with Modulation of the Integrin Repertoire in Glioblastoma, Impact of α5ß1 Integrin.

Despite extensive treatment, glioblastoma inevitably recurs, leading to an overall survival of around 16 months. Understanding why and how tumours resist to radio/chemotherapies is crucial to overcome this unmet oncological challenge. Primary and acquired resistance to Temozolomide (TMZ), the standard-of-care chemotherapeutic drug, have been the subjects of several studies. This work aimed to evaluate molecular and phenotypic changes occurring during and after TMZ treatment in a glioblastoma cell model, the U87MG. These initially TMZ-sensitive cells acquire long-lasting resistance even after removal of the drug. Transcriptomic analysis revealed that profound changes occurred between parental and resistant cells, particularly at the level of the integrin repertoire. Focusing on α5ß1 integrin, which we proposed earlier as a glioblastoma therapeutic target, we demonstrated that its expression was decreased in the presence of TMZ but restored after removal of the drug. In this glioblastoma model of recurrence, α5ß1 integrin plays an important role in the proliferation and migration of tumoral cells. We also demonstrated that reactivating p53 by MDM2 inhibitors concomitantly with the inhibition of this integrin in recurrent cells may overcome the TMZ resistance. Our results may explain some integrin-based targeted therapy failure as integrin expressions are highly switchable during the time of treatment. We also propose an alternative way to alter the viability of recurrent glioblastoma cells expressing a high level of α5ß1 integrin.

Sterculia tragacantha Lindl Leaf Extract Ameliorates STZ-Induced Diabetes, Oxidative Stress, Inflammation and Neuronal Impairment.

BACKGROUND: Sterculia tragacantha is a medicinal plant commonly used in the western part of Nigeria, for managing diabetes mellitus. However, there is a dearth of scientific information on the antidiabetic and neuroprotective properties of the plant. METHODS: The in silico, in vitro and in vivo models were used to evaluate the antioxidants, antidiabetic, anti-inflammatory and neuroprotective potential of aqueous extract of Sterculia tragacantha leaf (AESTL) in streptozotocin (STZ)-induced diabetic rats. Thirty (30) male albino rats (155.34±6.33 g) were intraperitoneal injected with 40 mg/kg of freshly prepared streptozotocin and were divided into 5 groups (A-E) of 6 animals each. Groups A-D were treated with 0, 150 and 300 mg/kg of AESTL, and 200 mg/kg body weight of metformin respectively, while group E serve as the normal control. RESULTS: The results of in vitro analysis revealed dose-dependent antioxidant activities; ABTS (IC50 = 63.03±2.57 µg/mL), DPPH (117.49±2.35 µg/mL), FRAP (15.19±0.98 mmol/100g), TAC (43.38±0.96 mg/100g), hypoglycaemic effect; α-amylase (IC50 = 77.21±4.35 µg/mL) and α-glucosidase (IC50 = 443.25±12.35), and anti-cholinesterase; AChE (IC50 = 113.07±3.42 µg/mL) and BChE (IC50 = 87.50±4.32 µg/mL) activities of AESTL. In vivo study revealed dose-dependent hypoglycemic effect and body weight improvement in rats treated with the AESTL. In addition, AESTL improved the antioxidant status and attenuated STZ-induced dysregulations of Na+-K+-ATPase, cholinesterases and neurotransmitters in the brain tissue of experimental rats. The results also demonstrated that AESTL could regulate anti-inflammatory response via inhibition of COX-2/NO signaling axis in the brain of diabetic rats. Molecular docking analysis revealed that epicatechin and procyanidin B2, the bioactive compounds from AESTL, docked well to the binding cavities of acetylcholinesterase, butyrylcholinesterase, α-amylase and α-glucosidase with binding affinities ranges between -8.0 and -11.4 kcal/mol, suggesting that these compounds are the bioactive component that could be responsible for the antidiabetic and neuroprotective activities of AESTL. CONCLUSION: The results of the present study strongly suggested that the AESTL extract could be very useful for halting diabetes progression and its associated neuroinflammation complications.

5-HT7 Receptor Is Involved in Electroacupuncture Inhibition of Chronic Pain in the Spinal Cord.

Knee osteoarthritis (KOA) is a common and disabling condition characterized by attacks of pain around the joints, and it is a typical disease that develops chronic pain. Previous studies have proved that 5-HT1, 5-HT2, and 5-HT3 receptors in the spinal cord are involved in electroacupuncture (EA) analgesia. The 5-HT7 receptor plays antinociceptive role in the spinal cord. However, it is unclear whether the 5-HT7 receptor is involved in EA analgesia. The 5-HT7 receptor is a stimulatory G-protein (Gs)-coupled receptor that activates adenylyl cyclase (AC) to stimulate cyclic adenosine monophosphate (cAMP) formation, which in turn activates protein kinase A (PKA). In the present study, we found that EA significantly increased the tactile threshold and the expression of the 5-HT7 receptor in the dorsal spinal cord. Intrathecal injection of 5-HT7 receptor agonist AS-19 mimicked the analgesic effect of EA, while a selective 5-HT7 receptor antagonist reversed this effect. Moreover, intrathecal injection of AC and PKA antagonists prior to EA intervention prevented its anti-allodynic effect. In addition, GABAA receptor antagonist bicuculline administered (intrathecal, i.t.) prior to EA intervention blocked the EA effect on pain hypersensitivity. Our data suggest that the spinal 5-HT7 receptor activates GABAergic neurons through the Gs-cAMP-PKA pathway and participates in EA-mediated inhibition of chronic pain in a mouse model of KOA.

Biological Relevance of RGD-Integrin Subtype-Specific Ligands in Cancer.

Integrins are heterodimeric transmembrane proteins able to connect cells with the micro-environment. They represent a family of receptors involved in almost all the hallmarks of cancer. Integrins recognizing the Arg-Gly-Asp (RGD) peptide in their natural extracellular matrix ligands have been particularly investigated as tumoral therapeutic targets. In the last 30 years, intense research has been dedicated to designing specific RGD-like ligands able to discriminate selectively the different RGD-recognizing integrins. Chemists' efforts have led to the proposition of modified peptide or peptidomimetic libraries to be used for tumor targeting and/or tumor imaging. Here we review, from the biological point of view, the rationale underlying the need to clearly delineate each RGD-integrin subtype by selective tools. We describe the complex roles of RGD-integrins (mainly the most studied αvß3 and α5ß1 integrins) in tumors, the steps towards selective ligands and the current usefulness of such ligands. Although the impact of integrins in cancer is well acknowledged, the biological characteristics of each integrin subtype in a specific tumor are far from being completely resolved. Selective ligands might help us to reconsider integrins as therapeutic targets in specific clinical settings.