Appraisal of the Antiarthritic Potential of Prazosin via Inhibition of Proinflammatory Cytokine TNF-α: A Key Player in Rheumatoid Arthritis

Molecular insights of Eucalyptol (1,8-Cineole) as an anti-arthritic agent: in vivo and in silico analysis of IL-17, IL-10, NF-κB, 5-LOX and COX-2

The monoterpene oxide, Eucalyptol (1,8-Cineole), a primary component of eucalyptus oil, has been evaluated pharmacologically for anti-inflammatory and analgesic activity. Current research aimed to evaluate Eucalyptol's anti-arthritic potential in a Complete Freund's adjuvant induced arthritis that resembles human rheumatoid arthritis. Polyarthritis developed after 0.1 mL CFA injection into the left hind footpad in rats. Oral administration of Eucalyptol at various doses (100, 200 and 400 mg/kg) significantly reduced paw edema, body weight loss, 5-LOX, PGE2 and Anti-CCP levels. Real-time PCR investigation showed significant downregulation of COX-2, TNF-α, NF-κB, IL-17, IL-6, IL-1β and upregulation of IL-4 and IL-10 in Eucalyptol treated groups. Hemoglobin and RBCs counts significantly increased post-treatment with Eucalyptol while ESR, CRP, WBCs and platelets count significantly decreased. Eucalyptol significantly increased Superoxide Dismutase, Catalase and Glutathione levels compared to CFA-induced arthritic control however, MDA significantly decreased post-treatment. Further, radiographic and histopathological examination of the ankle joints of rodents administered Eucalyptol revealed an improvement in the structure of the joints. Piroxicam was taken as standard. Furthermore, molecular docking findings supported the anti-arthritic efficacy of Eucalyptol exhibited high binding interaction against IL-17, TNF-α, IL-4, IL-10, iNOS NF-κB, 5-LOX, and COX-2. Eucalyptol has reduced the severity of CFA induced arthritis by promoting anti-inflammatory cytokines for example IL-4, IL-10 and by inhibiting pro-inflammatory cytokines such as 5-LOX, COX-2, IL-17, NF-κB, TNF-α, IL-6 and IL-1β. Therefore, Eucalyptol might be as a potential therapeutic agent because of its pronounced anti-oxidant and anti-arthritic activity.

Reimagining old drugs with new tricks: Mechanisms, strategies and notable success stories in drug repurposing for neurological diseases

Recent evolution in drug repurposing has brought new anticipation, especially in the conflict against neurodegenerative diseases (NDDs). The traditional approach to developing novel drugs for these complex disorders is laborious, time-consuming, and often abortive. However, drug reprofiling which is the implementation of illuminating novel therapeutic applications of existing approved drugs, has shown potential as a promising strategy to accelerate the hunt for therapeutics. The advancement of computational approaches and artificial intelligence has expedited drug repurposing. These progressive technologies have enabled scientists to analyse extensive datasets and predict potential drug-disease interactions. By prospecting into the existing pharmacological knowledge, scientists can recognise potential therapeutic candidates for reprofiling, saving precious time and resources. Preclinical models have also played a pivotal role in this field, confirming the effectiveness and mechanisms of action of repurposed drugs. Several studies have occurred in recent years, including the discovery of available drugs that demonstrate significant protective effects in NDDs, relieve debilitating symptoms, or slow down the progression of the disease. These findings highlight the potential of repurposed drugs to change the landscape of NDD treatment. Here, we present an overview of recent developments and major advances in drug repurposing intending to provide an in-depth analysis of traditional drug discovery and the strategies, approaches and technologies that have contributed to drug repositioning. In addition, this chapter attempts to highlight successful case studies of drug repositioning in various therapeutic areas related to NDDs and explore the clinical trials, challenges and limitations faced by researchers in the field. Finally, the importance of drug repositioning in drug discovery and development and its potential to address discontented medical needs is also highlighted.

Ameliorative effects of Atriplex crassifolia (C.A.Mey) on pain and inflammation through modulation of inflammatory biomarkers and GC-MS-based metabolite profiling

Atriplex crassifolia (A. crassifolia) is a locally occurring member of Chenopodiaceae family that has been used in folk medicine for the treatment of joint pain and inflammation. The present study was focused to determine the analgesic and anti-inflammatory potential of the plant. n-hexane (ACNH) and methanol (ACM) extracts of A. crassifolia were evaluated for in vitro anti-inflammatory potential using protein denaturation inhibition assay. In vivo anti-inflammatory potential was determined by oral administration of 250, 500, and 1000 mg/kg/day of extracts against carrageenan and formalin-induced paw edema models. Inflammatory mediators such as TNF-α, IL-10, IL-1β, NF-kB, IL-4, and IL-6 were estimated in blood samples of animals subjected to formalin model of inflammation. Analgesic activity was determined using acetic acid-induced writhing and tail flick assay model. Phytochemical profiling was done by GC-mass spectrophotometer. The results of in vitro anti-inflammatory activity revealed that both ACNH and ACM displayed eminent inhibition of protein denaturation in concentration-dependent manner. In acute in vivo carrageenan-induced paw edema model, both extracts reduced inflammation at 5th and 6th hour of study (p < 0.05). A. crassifolia extracts exhibited significant inhibition against formalin-induced inflammation with maximum effect at 1000 mg/kg. ACNH and ACM significantly augmented the inflammatory mediators (p < 0.05). Levels of TNF-α, IL-6, IL-1β, and NF-kB were reduced, while those of IL-4 and IL-10 were upregulated. ACNH displayed maximum analgesic effect at 1000 mg/kg, while ACM showed potent activity at 500 and 1000 mg/kg. The extracts restored the CBC, TLC and CRP toward normal. GC-MS analysis revealed the presence of compounds like n-hexadecanoic acid, Phytol, (9E,11E)-octadecadienoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester, 1-hexacosene, vitamin E, campesterol, stigmasterol, gamma sitosterol in both extracts. These compounds have been reported to suppress inflammation by inhibiting inflammatory cytokines. The current study concludes that A. crassifolia possesses significant anti-nociceptive and anti-inflammatory potential owing to the presence of phytochemicals.

Ultrasensitive Electrochemical Immunosensor for Multiplex Sandwich Bioassaying Based on the Functional Antibodies

In vitro diagnostics (IVDs) based on electrochemical immunosensors are crucial for disease screening, diagnosis, prognosis, and treatment monitoring. However, label-free electrochemical immunosensors commonly suffer from poor specificity, leading to false positives. To address this issue, we propose a highly sensitive and precise electrochemical immunosensor for protein marker detection. This approach involves directly labeling the detection antibodies (Ab2) with thionine (Thi). The Ab2 labeled by Thi exhibits a distinct redox peak upon targeted voltage stimulation, enabling accurate quantification of protein biomarkers. Thi-modified antibodies provide significant advantages over traditional antibody modification methods, such as enhanced detection sensitivity, improved accuracy, and specificity in protein marker identification. The method is straightforward and efficient, ensuring specific analyte detection while minimizing interference from other substances in the sample. Additionally, a multielectrode detection method was employed, achieving remarkably low limits of detection (LoDs) for tumor necrosis factor-alpha (TNF-alpha), cardiac troponin I (cTnI), and interleukin-6 (IL-6), with LoDs of 9.38 fg/mL, 1.70 fg/mL, and 8.14 fg/mL, respectively. The proposed electrochemical immunosensor also exhibited high selectivity and repeatability, with relative standard deviations (RSD) of 6.39% for TNF-alpha, 2.42% for cTnI, and 2.72% for IL-6 (n = 5). Moreover, it demonstrated high sensitivity and was evaluated for serum detection using the standard addition method. The results highlight the great potential of the proposed electrochemical immunosensor for clinical applications, offering a novel approach for future utilization in clinical settings.

Attenuation of CFA-induced arthritis through regulation of inflammatory cytokines and antioxidant mechanisms by Solanum nigrum L. leaves extracts

Solanum nigrum L. is a popular traditional medicine for various inflammatory conditions including rheumatism and joint pain. The current study aimed to evaluate the anti-arthritic mechanism of Solanum nigrum L. Four extracts were prepared using n-hexane, methanol, chloroform, and water. The anti-nociceptive and anti-inflammatory activity was carried out with 100, 200, and 300 mg/kg body wt. PO of each extract by the hot plate and carrageenan-induced paw oedema methods, respectively. The anti-arthritic study was performed with chloroform and aqueous extracts (300 mg/kg) in complete Freund's adjuvant (CFA)-induced arthritis. Paw size (mm), ankle joint diameter (mm), and latency time (sec) were recorded on day 0 and every 4th day till 28 days. The hematological, inflammatory, and oxidative biomarkers were estimated. Results showed that significant analgesia (p < 0.05) and reduction in paw inflammation were achieved with all extracts. The highest percent inhibition in Carrageenan-induced inflammation was achieved with 300 mg/kg of chloroform (72.19%) and aqueous (71.30%) extracts, respectively. In the CFA model, both extracts showed a significant reduction in paw size and ankle joint diameter (p < 0.05). The RT-qPCR analysis revealed the upregulation of interleukin-4 and interleukin-10, and down-expression of interleukin-1β, interleukin-6, tumor necrosis factor-α, cycloxygenase-2, nuclear factor-κB, prostaglandin E synthase 2, and interferon-γ. A significant increase in superoxide dismutase, catalase, and glutathione levels was observed. Hence, it is concluded that Solanum nigrum L. leaf extracts regulate the expression of inflammatory markers and improve oxidative stress resulting in the attenuation of CFA-induced arthritis.

Naringenin ameliorates collagen-induced arthritis through activating AMPK-mediated autophagy in macrophages

BACKGROUND

Naringenin is widely recognized for its notable attributes, including anti-inflammatory, anti-cancer, and immunomodulatory activities. However, its specific implications for rheumatoid arthritis (RA) and the underlying mechanisms remain to be explored. This study aimed to investigate the therapeutic efficacy and pharmacological mechanism of Naringenin in the treatment of collagen-induced arthritis (CIA).

METHODS

A CIA model was established in DBA/1 mice, and various doses of Naringenin were administered orally to assess its impact on RA. The study also involved lipopolysaccharides (LPS)-induced RAW264.7 cells to further evaluate the effects of Naringenin. Mechanistic studies were conducted to elucidate the signaling pathways involved in Naringenin's actions.

RESULTS

Naringenin significantly alleviated foot inflammation in DBA/1 CIA mice and attenuated the levels of pro-inflammatory cytokines in serum. It also enhanced antioxidant capacity in the CIA model. In vitro studies with LPS-induced RAW264.7 cells demonstrated that Naringenin attenuated pro-inflammatory cytokines and reactive oxygen species (ROS) levels. Mechanistic studies confirmed that Naringenin activated autophagy and increased autophagic flux. Blocking autophagy, either by silencing Atg5 or inhibiting autophagolysosome using chloroquine, effectively counteracted the impact of Naringenin on pro-inflammatory cytokines. Further exploration revealed that Naringenin activated the AMPK/ULK1 signaling pathway, and inhibition of AMPK reversed the initiation of autophagy and reduced pro-inflammatory cytokine secretion induced by Naringenin.

CONCLUSIONS

This study unveils a novel mechanism by which Naringenin may be used to treat RA. It demonstrates the therapeutic efficacy of Naringenin in a CIA model by reducing inflammation, modulating cytokine levels, and enhancing antioxidant capacity. Moreover, the activation of autophagy through the AMPK/ULK1 signaling pathway appears to play a critical role in Naringenin's anti-inflammatory effects. These findings suggest potential strategies for the development of anti-rheumatic medications based on Naringenin.

Attenuation of CFA-induced chronic inflammation by a bicyclic monoterpene fenchone targeting inducible nitric oxide, prostaglandins, C-reactive protein and urea

Fenchone (a bicyclic monoterpene) is present in the essential oils of plant species like Foeniculum vulgare and Peumus boldus and is used to treat GIT disorders. Research reports have indicated its strong anti-inflammatory, antioxidant, and anti-nociceptive properties. The present study was designed to investigate fenchone's anti-arthritic effects in a rat model of chronic joint inflammation (Complete Freud's Adjuvant-mediated inflammation [CFA]). Molecular docking analysis revealed a high binding interaction of fenchone with inducible nitric oxide synthase (iNOS), Interleukin-17, Prostaglandin E Receptor EP4, and Cycloxygenase-2 (COX-2), indicating its anti-inflammatory efficacy using computational tests. Fenchone treatment at 100 mg/kg, 200 mg/kg, and 400 mg/kg significantly enhanced the tail-flick latency when compared with the solvent-treated group. Correspondingly, the raised mRNA values of iNOS, IL-17, IL-1β, IL-6, TNF-α, and COX-2 in solvent-treated group were significantly reduced following treatment with fenchone. Moreover, fenchone significantly lowered spleen and thymus indices, Nitric oxide (NO) and PGE2 values as compared to solvent-treated group. Hence, the results of the present study indicated that fenchone has a potent anti-inflammatory effect by inhibiting pro-inflammatory markers and thus may have therapeutic potential for chronic joint inflammation as well as chronic inflammatory disorders.

Antiarthritic potential of the butanol fraction of Sesuvium sesuvioides: An in vitro, in vivo, and in silico evaluation

Sesuvium sesuvioides (Fenzl) Verdc (Aizoaceae) has been traditionally used in the treatment of inflammation, arthritis, and gout. However, its antiarthritic potential has not been evaluated scientifically. The current study was designed to assess the antiarthritic properties of the n-butanol fraction of S. sesuvioides (SsBu) by phytochemical analysis, in vitro and in vivo pharmacological activities, and in silico studies. Phytochemical analysis showed total phenolic contents (90.7 ± 3.02 mg GAE/g) and total flavonoid contents (23.7 ± 0.69 mg RE/g), and further analysis by GC-MS identified possible bioactive phytocompounds belonging to phenols, flavonoids, steroids, and fatty acids. The in vitro antioxidant potential of SsBu was assessed by DPPH (175.5 ± 7.35 mg TE/g), ABTS (391.6 ± 17.1 mg TE/g), FRAP (418.2 ± 10.8 mg TE/g), CUPRAC (884.8 ± 7.97 mg TE/g), phosphomolybdenum (5.7 ± 0.33 mmol TE/g), and metal chelating activity (9.04 ± 0.58 mg EDTAE/g). Moreover, in the in vitro studies, inhibition (%) of egg albumin and bovine serum albumin denaturation assays showed that the anti-inflammatory effect of SsBu at the dose of 800 μg/ml was comparable to that of diclofenac sodium used as a standard drug. The in vivo antiarthritic activity was assessed to determine the curative impact of SsBu against formalin-induced (dose-dependent significant (p < 0.05) effect 72.2% inhibition at 750 mg/kg compared to standard; 69.1% inhibition) and complete Freund's adjuvant-induced arthritis (40.8%; inhibition compared to standard, 42.3%). SsBu significantly controlled PGE-2 level compared to the control group (p < 0.001) and restored the hematological parameters in rheumatoid arthritis. Treatment with SsBu significantly reduced oxidative stress by reinstating superoxide dismutase, GSH, and malondialdehyde along with pro-inflammatory markers (IL-6 and TNF-α) in arthritic rats. Molecular docking revealed the antiarthritic role of major identified compounds. Kaempferol-3-rutinoside was found to be more potent for COX-1 (-9.2 kcal/mol) and COX-2 inhibition (-9.9 kcal/mol) than diclofenac sodium (COX-1, -8.0 and COX-2, -6.5 kcal/mol). Out of the 12 docked compounds, two for COX-1 and seven for COX-2 inhibition showed more potent binding than the standard drug. The results from the in vitro, in vivo, and in silico approaches finally concluded that the n-butanol fraction of S. sesuvioides had antioxidant and antiarthritic potential, which may be due to the presence of potential bioactive compounds.

Enalapril attenuated CFA provoked arthritic manifestation by modulating proinflammatory and anti-inflammatory cytokine network

Enalapril with documented anti-inflammatory potential was evaluated in current investigation to explore its anti-arthritic efficacy. For anti-arthritic evaluation of enalapril, CFA-instigated arthritic model was employed after which various parameters comprising paw volume, body weight, arthritic index, hematological and biochemical parameters, radiographic analysis and level of various cytokines were estimated. Enalapril demonstrated significant (p˂0.001) anti-arthritic activity by suppressing paw volume, arthritic index while preserved CFA instigated weight loss. Likewise, enalapril also normalized the hematological and biochemical alterations, suppressed the level of proinflammatory cytokines with elevation of anti-inflammatory cytokines. Radiographic and histopathological analysis also further validates the anti-arthritic attribute of enalapril where enalapril preserved the normal architecture of arthritis induced joints. Outcomes of the study pointed out a notable anti-arthritic activity of enalapril. However detailed mechanistic studies are still required to point out the exact mechanism of action.

Tumor necrosis factor-alpha, prostaglandin-E2 and interleukin-1β targeted anti-arthritic potential of fluvoxamine: drug repurposing

Fluvoxamine, a selective serotonin re uptake inhibitor, is used to treat depression. The aim of present study was to evaluate fluvoxamine in acute (egg albumin-induced inflammation) and chronic inflammatory rat models (formaldehyde and complete Freund's adjuvant (CFA)-induced arthritis). Fluvoxamine showed highly significant (p<0.001) protective effect at dose of 50 mg/kg orally with percentage suppression 21.3% as compared to disease control group in acute model. Likewise, formaldehyde-induced arthritic experiment confirmed the significant (p<0.001) anti-arthritic behavior, showed by fluvoxamine (50 mg/kg orally) throughout the study. Moreover, In CFA-induced model, the higher dose (fluvoxamine 50 mg/kg) exhibited highly significant (p<0.001) decrease in paw thickness and arthritic score with significant increase in weight of animals from 123.8± 1.934 g to 130.2± 1.655 g, significantly decreased the level of RF and CRP to level of 12.0±0.707 and 11.40±0.50 respectively and restoration of SOD, CAT (69.8±1.5, 72.0±1.4 respectively). Furthermore, the level of TNF-α, PGE2, and IL-1β (147.0±2.0, 406.8±2.5, and 93.8±1.3 respectively) in arthritic animals was reduced to significant (p<0.001) level (53.8±1.3, 205±3.6, and 42.0±1.4 respectively) after treatment with fluvoxamine. Furthermore, molecular docking of fluvoxamine against TNF-α, PGE2, and IL-1β protein targets showed good binding energies which hereby from computational studies proves our compound anti-inflammatory potential. In addition, absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies reveled that fluvoxamine has very good pharmacokinetic profile with no specific hepatic toxicity and good absorption level. In addition, the skin sensitization test in vitro human cell line activation test (h-CLAT) and KeratinoSens have revealed that isolated flavone is not skin sensitive with confidence score of 59.6% and 91.6%. The current findings validated the anti-arthritic potential of fluvoxamine but it should be recommended for clinical investigation in future research.

Regulatory NK cells in autoimmune disease

NK cells are defined as the major components of the immunological network which exerts defense against tumors and viral infections as well as regulation of innate and adaptive immunity, shaped through interaction with other cells like T cells. According to the surface markers, NK cells can be divided into CD56dim NK and CD56bright NK subsets. CD56bright NK cells usually are known as regulatory NK cells. Once the immune system loses its self-tolerance, autoimmune diseases develop. NK cells and their subsets can be altered during autoimmune diseases, indicative of their prominent regulatory roles and even pathological and protective functions in autoimmune disorders. In this regard, activation of CD56bright NK cells can suppress activated autologous CD4+ T cells and subsequently prevent the initiation of autoimmunity. In this review article, we summarize the roles of regulatory NK cells in autoimmune disease occurrence which needs more research to uncover their exact related mechanism. It seems that targeting NK cells can be a promising therapeutic platform against autoimmune diseases.