Methotrexate and its mechanisms of action in inflammatory arthritis Nature Reviews Rheumatology
Methotrexate and its mechanisms of action in inflammatory arthritis Nature Reviews Rheumatology
Plasma levels of cholesterol, HDL cholesterol, and triglycerides were determined on a Cobas Integra Analyzer (Roche Diagnostics, Rotkreuz, Switzerland). Fasting plasma glucose was measured in duplicate immediately after sampling on a Beckman Glucose Analyzer II (Beckman Instruments, Palo Alto, CA). Serum FFAs were measured enzymatically using a Wako NEFA (nonesterified fatty acid) Test Kit (Wako Chemicals, Richmond, VA). Plasma insulin levels were determined using an ultrasensitive Rat Insulin ELISA (enzyme-linked immunosorbent assay) Kit from DRG Diagnostics (Marburg, Germany).
In general, it can be concluded that AICAR, administered starting from the seventh week of the study, contributes to the reduction in absolute body weight and weight gain in animals receiving HFD. Recent research has shown that the tumour microenvironment has played a vital role in promoting tumour initiation and progression by modulating the extracellular matrix and immune cell homing [102]. We noticed that AICAR treatment could block the proliferation of stromal cells, including alveolar macrophages, endothelial cells, and fibroblasts. Tumour-adjacent stromal cells promote tumour initiation and progression by providing paracrine signals [103].
Compound-13
- Yeast is a good experimental system to study the effects of AICAr that are AMPK-independent as the yeast AMPK orthologue SNF1 is activated by ADP rather than AMP, and genes strongly regulated by Snf1p are not identical to AICAr-regulated transcription.
- As shown in Figure 3, AICA ribotide (AICAR) or ZMP is a normal cellular intermediate in de novo purine synthesis.
- The beneficial effect of regular physical exercise on critical components of the insulin resistance syndrome (IRS) is well established (1).
- The cell cycle analyses of AICAr-arrested cells in some studies revealed an increase in the proportion of cells in the G0/G1 phase, as would be expected from the mechanism of cell cycle arrest in response to AMPK activation and mTORC1 inhibition [23].
- After determining the effects of AICAR/Compound C on T cell survival, we next investigated whether these agents affect T cell activation.
- Adiponectin and IL-6 are activators of AMPK [13, 14], whereas TNF-α is an inhibitor of AMPK [66, 67].
MUC1-CT has become a promising druggable target for treating cancer patients in preclinical models [31,32,33]. Even though the small molecule apigenin was reported to inhibit MUC1-CT dimerisation in the breast cancer cell lines, the inhibitory effect was probably mediated by blocking other targets [34,35,36,37]. Finding new small molecules directly blocking MUC1-CT will offer novel opportunities to treat MUC1-dependent lung tumours. Having shown transcription factor-specific inhibition of transcriptional activation by AICAR, we questioned the ability of AICAR to interfere with binding of transcription factors to DNA using electrophoretic mobility shift (EMSA) assays. Nuclear extracts were prepared from macrophages stimulated with LPS, IL-6 or cultured under hypoxia to achieve nuclear accumulation of NFκB, STAT3, or HIF1α, respectively.
Based on these results, AICAR-induced metabolic improvements were suggested to be more prominent in type II(B) fibers than in type I fibers. The cell cycle analyses of AICAr-arrested cells in some studies revealed an increase in the proportion of cells in the G0/G1 phase, as would be expected from the mechanism of cell cycle arrest in response to AMPK activation and mTORC1 inhibition [23]. However, in embryonic stem cells, AICAr increased the cell population at both G1 and non-cycling S phases [85]. Furthermore, an arrest in the S phase has been observed in MEFs [86], cancer cell lines [94], and leukemia cells [95]. To understand the mechanism responsible for proliferation arrest in response to AICAr, we have to go back to the role of endogenous AICAR in de novo purine synthesis that has been well-known to affect cell growth much before the discovery of the role of AICAr in AMPK activation. Chemical reagents that target AMPK activity have been widely used to investigate cellular functions of AMPK [7-10].
Our previous work discovered AMPK-independent effects of AICAR on lipid metabolism and endoplasmic reticulum (ER) stress responses of human macrophages19,20. Conducting these studies we noticed that AICAR attenuated inflammatory responses of human macrophages to stimuli such as bacterial lipopolysaccharide. Similar observations have been reported, but how AICAR modulates inflammatory responses is still obscure21,22,23,24. We aimed to elucidate how AICAR interferes with LPS-induced inflammatory activation of human primary macrophages. Two isoforms exist for the α-subunit (α۱ and α۲) and the β-subunit (β۱ and β۲), with three isoforms for the γ-subunit (γ۱, γ۲, and γ۳). The α-subunit contains the serine/threonine kinase domain, which has been shown to exhibit kinase activity when it is phosphorylated by upstream kinases such as LKB1 and CaMKK [3, 4].
Co-targeting EGFR and JAK with AICAR reduce organoid growth from PDX and transgenic mouse tumour
In the yeast model, disruption of nucleotide homeostasis was identified as a crucial feature of AICAr toxicity [99], suggesting the similar role of nucleotide metabolism in AMPK-independent growth arrest induced by an exogenous AICAr in human cell lines. In this study, our data has demonstrated that extrinsic AICAR treatment induces apoptosis and increases DNA damage in EGFR-mutant lung cancer cell lines. AICAR reduces JAK-STAT signalling by blocking physical protein–protein interactions between MUC1-CT and JAK1. AICAR treatment also reduces EGFR protein stability and activity as well as MUC1-CT expression. Clinically, higher expression of MUC1 correlates with less overall and disease-free survival in lung adenocarcinoma patients at advanced stages.
AICAR acts by entering nucleoside pools https://indiaaparicio.de/exploring-the-effects-of-anabolic-drugs-on-muscle-6/ and significantly increasing levels of adenosine during periods of ATP breakdown (2). All animal research complied with protocols approved by the Institutional Animal Care and Use committees (IACUC) from BIDMC, Yale University, and UCF. EGFR T790M-L858R (EGFR TL)/CCSP-rtTA bi-transgenic mice and tetO-Cre transgenic mice were previously described [63]. To induce EGFR TL expression, 6-week-old female mice were fed a doxycycline (Dox) diet (Envigo) continuously for 0–۱۴ weeks (EG0, EG1, EG2, EG10, EG14). Among these mice, one group fed a Dox diet for 8 weeks was followed by a regular diet for 2 weeks (EG8OFF2).