Two inhibitors of DNA-synthesis lead to inhibition of cytokine production via a different mechanism

The Protective Effects of Nutraceutical Components in Methotrexate-Induced Toxicity Models—An Overview

There are multiple concerns associated with methotrexate (MTX), widely recognized for anti-neoplastic and anti-inflammatory effects in life-threatening disease conditions, i.e., acute lymphoblastic leukemia, non-Hodgkin’s lymphoma, psoriasis, and rheumatoid arthritis, due to long-term side effects and associated toxicity, which limits its valuable potential. MTX acts as an inhibitor of dihydrofolate reductase, leading to suppression of purine and pyrimidine synthesis in high metabolic and turnover cells, targeting cancer and dysregulated immune cells. Due to low discrimination between neoplastic cells and naturally high turnover cells, MTX is prone to inhibiting the division of all fast-dividing cells, causing toxicity in multiple organs. Nutraceutical compounds are plant-based or food-derived compounds, used for their preventive and therapeutic role, ascertained in multiple organ dysfunctions, including cardiovascular disease, ischemic stroke, cancer, and neurodegenerative diseases. Gut microbiota and microbiota-derived metabolites take part in multiple physiological processes, their dysregulation being involved in disease pathogenesis. Modulation of gut microbiota by using nutraceutical compounds represents a promising therapeutic direction to restore intestinal dysfunction associated with MTX treatment. In this review, we address the main organ dysfunctions induced by MTX treatment, and modulations of them by using nutraceutical compounds. Moreover, we revealed the protective mechanisms of nutraceuticals in MTX-induced intestinal dysfunctions by modulation of gut microbiota.

Characterization of the impact of GMP/GDP synthesis inhibition on replicative lifespan extension in yeast

Slowing down aging-associated accumulation of molecular damage or its prevention represents a promising therapeutic paradigm to combat aging-related disease and death. While several chemical compounds extend lifespan in model organisms, their mechanism of action is often unknown, reducing their therapeutic potential. Using a systematic approach, here we characterize the impact of the GMP pathway on yeast lifespan and elucidate GMP synthesis inhibition as a lifespan extension mechanism. We further discover that proteasome activation extends lifespan in part through the GMP pathway. GMP synthesis inhibition exerts its lifespan extension effect independently of the canonical nutrient-sensing pathway regulating lifespan. Exposing longitudinally aging yeast cells to GMP pathway inhibition in an age-dependent manner, we demonstrate that the lifespan extension is facilitated by slowing, rather than reversing, the aging process in cells. Using a GUK1 mutant with lower GMP-to-GDP conversion activity, we observe lifespan extension, suggesting that reduced GDP level by itself can also extend yeast lifespan. These findings elucidate the involvement of nucleotide metabolism in the aging process. The existence of clinically-approved GMP pathway inhibitors elicits the potential of a new class of therapeutics for aging-related disorders.

The RORγt-CCR6-CCL20 axis augments Th17 cells invasion into the synovia of rheumatoid arthritis patients

OBJECTIVES

To clarify the pathogenic role of transcription factor expression of CD4 + T helper (Th) cell subsets in the development of rheumatoid arthritis (RA).

METHODS

We collected CD4 + T cells from peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) by magnetic cell sorting. The proportion of Th cell subsets were classified from cell surface markers (CD45RA, CXCR5, CXCR3, CCR6) and the expression of their transcription factors (T-bet, GATA3, RORγt) were analyzed by flow cytometry before and at 24 weeks after anti-rheumatic treatment. Chemotaxis assays quantified migratory ability.

RESULTS

The expression of CCR6 and RORγt in Th17 cells from PBMC of RA patients was significantly higher than in healthy control volunteers and osteoarthritis patients. The proportion of Th17 cells in SFMCs of RA patients was significantly higher than that in PBMCs. Chemotaxis assays revealed that the migration index of Th17 cells towards CCL20 was remarkably enhanced in RA patients. The expression of CCR6 and RORγt in Th17 cells at 24 weeks post-therapeutic intervention was significantly decreased compared to before treatment.

CONCLUSION

The high expression of RORγt might facilitate the migration of Th17 cells to inflamed joints via the enhanced expression of CCR6 and contribute to the pathology of RA.

1-Methyl-tryptophan synergizes with methotrexate to alleviate arthritis in a mouse model of arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease with no known cure. Current strategies to treat RA, including methotrexate (MTX), target the later inflammatory stage of disease. Recently, we showed that inhibiting indoleamine-2,3-dioxygenase (IDO) with 1-methyl-tryptophan (1MT) targets autoantibodies and cytokines that drive the initiation of the autoimmune response. Therefore, we hypothesized that combining 1MT with MTX would target both the initiation and chronic inflammatory phases of the autoimmune response and be an effective co-therapeutic strategy for arthritis. To test this, we used K/BxN mice, a pre-clinical model of arthritis that develops joint-specific inflammation with many characteristics of human RA. Mice were treated with 1MT, MTX, alone or in combination, and followed for arthritis, autoantibodies, and inflammatory cytokines. Both 1MT and MTX were able to partially inhibit arthritis when used individually; however, combining MTX + 1MT was significantly more effective than either treatment alone at delaying the onset and alleviating the severity of joint inflammation. We went on to show that combination of MTX + 1MT did not lower inflammatory cytokine or autoantibody levels, nor could the synergistic co-therapeutic effect be reversed by the adenosine receptor antagonist theophylline or be mimicked by inhibition of polyamine synthesis. However, supplementation with folinic acid did reverse the synergistic co-therapeutic effect, demonstrating that, in the K/BxN model, MTX synergizes with 1MT by blocking folate metabolism. These data suggest that pharmacological inhibition of IDO with 1MT is a potential candidate for use in combination with MTX to increase its efficacy in the treatment of RA.

Synoviocyte apoptosis may differentiate responder and non-responder patients to methotrexate treatment in rheumatoid arthritis

We aimed to evaluate whether methotrexate (MTX) in vitro induces apoptosis in synoviocytes obtained from rheumatoid arthritis patients and whether the apoptosis inducing effect of MTX to synoviocytes is correlated with the clinical responsiveness to MTX in patients with rheumatoid arthritis (RA). We evaluated 18 patients with RA taking MTX 15-20 mg/week as the subject group (nine responders and nine non-responders) and ten patients with osteoarthritis (OA) and nine patients with ankylosing spondylitis (AS) as the control group. Synoviocytes, cultured from the synovial fluid of the knee joint of each subject, were used for experiments between passages 4 and 6, and were treated with MTX. The induction of apoptosis was determined by the quantification of DNA hypoploidy by flow cytometry, nuclear morphology, caspases activation, DNA electrophoresis, and mitochondrial membrane potential measurements. The viability of synoviocytes treated with MTX was different between the MTX responders and nonresponders. MTX induced apoptosis in cultured synoviocytes by mitochondria- and caspase-dependent manners in the MTX responders but did not in the MTX non-responder, OA, and AS patients. The apoptotic responsiveness of the synoviocytes to MTX predicts the sensitivity to MTX treatment and provides a method determine the early application of an anti-tumor necrosis factor-α agent in RA treatment.

Methotrexate ameliorates pristane-induced arthritis by decreasing IFN-γ and IL-17A expressions

OBJECTIVE

This study was carried out to test the effects of methotrexate (MTX) and black seed oil (BSO) on pristane-induced arthritis (PIA) in rats.

METHODS

Inbred dark agouti (DA) rats were induced by a single subcutaneous injection of pristane, and then treated with MTX or BSO. Arthritis severity was evaluated macroscopically and microscopically. Plasma nitric oxide (NO) concentration was determined by the Griess method and cytokine mRNA expression in the spleen was detected by the real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

The clinical arthritis severity was decreased after MTX treatment, while the BSO groups did not show significant changes compared with the disease group. The plasma NO level of the MTX group was significantly decreased compared with the disease group, but the BSO groups showed no difference from the disease group in plasma NO levels. The interferon-γ (IFN-γ) and interleukin-17A (IL-17A) mRNA expressions in the spleens were significantly decreased in the MTX group, but only showed a declining trend in the BSO groups compared with the disease group. Neither MTX nor BSO had an effect on the mRNA expressions of IL-4, transforming growth factor β (TGF-β), and tumor necrosis factor-α (TNF-α) in the spleen.

CONCLUSIONS

MTX, but not BSO, can reduce the arthritis severity and decrease the mRNA expressions of IFN-γ and IL-17A in pristane-induced arthritis of rats.

Pilot study of safety and effect of combined intravitreal bevacizumab and methotrexate for neovascular age-related macular degeneration

PURPOSE

To evaluate the safety and effect of combined intravitreal methotrexate and bevacizumab on choroidal neovascularization in age-related macular degeneration (AMD).

METHODS

Seven eyes of 7 patients (4 female; mean age 65.43±5.96 years) with choroidal neovascularization secondary to AMD were studied. Patients received intravitreal injection of methotrexate and bevacizumab and were examined every 1.5 months. Reinjections were performed with bevacizumab only.

RESULTS

Three patients had 3 months, 3 had 4.5 months, and 1 had 8 months of follow-up. Mean number of reinjections was 2.0. In all patients, best-corrected visual acuity (BCVA) improved compared to baseline. Central macular thickness (CMT) decreased in all but one patient who had no reduced visual acuity. Mean BCVA (logMAR) was 1.27±0.43 D at baseline, 1.1±0.38 D at week 6, and 0.93±0.31 D at month 3. Mean BCVA in 3 patients at 4.5 months was 1.1±0.15 D. There were statistically significant differences between BCVA before injection and at week 6 (p=0.017), 3 months (p=0.005), and 4.5 months (p=0.04). Mean baseline CMT was 389±177 µm, 371±154 µm at 6 weeks, and 317±108 µm at 3 months. Mean CMT in 3 patients at 4.5 months was 266±66 µm. There were no statistically significant differences between baseline CMT and after treatment. No scar formation, increase of scar, or adverse reaction to methotrexate injection were seen.

CONCLUSIONS

Addition of intravitreal methotrexate to bevacizumab was safe in 7 eyes of 7 patients. It may enhance the therapeutic effect in regression of neovascularization in AMD and may reduce development of a fibrous component and disciform scar formation.