AICAR ameliorates high-fat diet-associated pathophysiology in mouse and ex vivo models, independent of adiponectin

Our results not only reveal the critical role of AMPK in regulating T cell survival and function, but also demonstrate AMPK-dependent and independent rolesof AICAR/Compound C in regulating T cell responses, thus suggesting a context-dependent effect of these “AMPK regulators”. We found that AICAR ameliorates muscular atrophy in SMNΔ7 as a consequence of the increase in myofiber size, which appears to be responsible for the modest increase in body weight of diseased animals treated with the compound. This is in contrast to the absence of changes in the cross-sectional area of myofibers reported in the dystrophic muscle of mdx mice following chronic treatment with AICAR 51. Differences in the physiological and histopathological alterations occurring in muscles affected by SMA and in dystrophic muscles (see, e.g., 93) could account for the discrepancies existing between these mouse models regarding the effects of AICAR on myofiber size. However, in agreement with findings reported in mdx mice 51, we also observed that AICAR increases the proportion of type I slow-twitch myofibers in SMNΔ7 mice. It is important to note that in basal (saline-treated) conditions we observed that muscles from SMNΔ7 mice had a dramatic increase in the proportion of type I fibers in a predominantly fast muscle, the TA.

Nrf2 Knockout Weakens the Protective Effects of AICAR on PALI in L-Arginine-Induced SAP Mice

• We have previously shown that AMPK’s anti-inflammatory function depends on macrophage SIRT1 11.
• Upregulated MUC1-CT binds to and activates downstream effectors, such as signal transducer and activator of transcription 3 (STAT3), resulting in increased cell proliferation 30.
• Part of the liver tissues was harvested and fixed in 4% buffered formaldehyde and embedded in paraffin for histological analysis or snap frozen and stored at -80°C.
• The supernatants underwent overnight immunoprecipitation with anti-p65 antibody (SC-372, Santa Cruz, Santa Cruz, CA), elution, reverse cross-link, and protease K digestion.
• Meanwhile, the recovery assay was performed to evaluate the accuracy and precision of the sample preparation method.

Taken together, these data suggest that T cell activation does not require AMPK expression and both AICAR and Compound C are able to inhibit T cell activation in an AMPK-independent manner. In our previous studies using AMPK conditional knockout mice, we have demonstrated that expression of AMPK in T cells is indispensable for their activation, but critical to promoting their survival and anti-tumor functions in mouse tumor models 10. Thus, clinical application of AMPK agonists/antagonists will most likely influence T cell survival and function.

We explored the hypothesis that the molecular basis of AICAR in improving PALI is attributed to its anti-inflammatory capability. These observations confirm that AICAR treatment protects against PALI in sodium taurocholate-induced SAP rats, likely by inhibiting the inflammatory response in the liver. As shown in Figure 3, AICA ribotide (AICAR) or ZMP is a normal cellular intermediate in de novo purine synthesis. AICAR or ZMP is increased in Lesch-Nyhan syndrome, one of the most common disorders of purine and pyrimidine metabolism.

Therefore, the mechanisms involved in the activation of AMPK to reduce liver injury may be complicated and further investigations are required to explain more specific mechanisms. Approximately every 15 persons die of lung cancer in an hour in the US in 2022, accounting for 21% of all site cancer patients’ death hourly 38. The death rate has dropped by three persons per hour compared to statistics in 2000 39.

NF-κB is a ubiquitous transcription factor that is activated by a variety of cytokines and mitogens and is thought to be a key regulator of genes involved in inflammation, responses to infection, and stress 18. The signaling pathways that mediate NF-κB activation can be classified into canonical and noncanonical pathways. In the present study, we found high expression of P-IκB/IκB ratio, P100, and p52, the important signaling proteins of canonical and noncanonical pathways, in BDL rats. Additionally, specific noncanonical NF-κB target genes CCL19 and CCL21 had a higher expression in BDL rats of this study, indicating that the both canonical and noncanonical NF-κB pathways play an important role in the occurrence of chronic cholestatic diseases. Anyhow, it is not the first time that the role of ROS in aging, cancer, and cell biology is undermined 38. It has been shown that the reduction of free radicals by N-acetyl cysteine not only did not improve the overall survival but also further intensified the metastasis of the tumor cells in a murine model of melanoma 40 and lung cancer 41.

The following experiments used 22Rv1 cells to explore the inhibitory effect of AICAR in prostate cancer. To examine whether AICAR affects the colony growth under anchorage-independent conditions, 22Rv1 cells were treated with different concentrations (0, 0.25, 0.5 and 1 mM) of AICAR and then a soft agar assay was conducted. The experimental results showed that AICAR suppressed growth of 22Rv1 cells in soft agar in a dose-dependent manner (Figure 2). CD4+ T cells separated from lymph nodes of WT and KO mice with a flow sorter were pretreated with DMSO, Compound C (10μM) and AICAR (500μM) for 30 minutes, and then stimulated with PMA(10ng/ml)/Ionomycin (1000ng/ml) for 20 minutes. Phosphorylation of ERK, S6K, S6P, 4EBP1 in total cells was analyzed by western blotting A..

Next, we focused on dissecting the deeper molecular mechanism by which AICAR inhibits oxidative stress and Nebido 1000mg/amp inflammation in the liver tissues of sodium taurocholate-induced SAP rats by activating AMPK phosphorylation. We performed Western blot to test the nuclear translocation of Nrf2 and the protein expression of NLRP3 as well as its downstream proteins caspase-1 and cleaved IL-1β in hepatic tissues of sodium taurocholate-induced SAP rats after treatment with AICAR. The nuclear translocation of Nrf2 was increased following sodium taurocholate treatment, whereas AICAR supplementation further promoted the nuclear accumulation of Nrf2 (Figures 4A,C).

In the present study, we investigated whether activation of AMPK by AICAR limits the inflammatory response and oxidative stress in the progression of PALI in two rodent models of severe acute pancreatitis (SAP) via Nrf2-mediated antioxidant effects and NLRP3 inflammasome activation. Our results provide the first direct evidence of the beneficial effects of pharmacological activation of AMPK by AICAR against the progression of PALI, including reduced redox stress and decreased NLRP3 inflammasome activation. Moreover, Nrf2 deficiency dramatically weakened these beneficial effects of AICAR in L-arginine-induced PALI mice.

Co-targeting EGFR and JAK with AICAR reduce organoid growth from PDX and transgenic mouse tumour

AICAR injection also significantly improved glucose tolerance and insulin sensitivity as assessed by GTT and ITT, respectively (Fig. 1C and 1D). Our data confirm previous observations that AICAR ameliorates insulin resistance in obese animal models 13, 14, 15. However, our low dose of AICAR treatment improved insulin sensitivity without changes of body weight and adiposity, suggesting that other beneficial effects independent of adiposity regulation may play a role in AICAR’s insulin-sensitizing effects. The fact that more AICAR is needed to elicit effects in aged mice is supported by other studies.

Figure 3.

This protective effect is attributed to increased glucose uptake, fatty acid oxidation, and mitochondrial function. AICAR‘s primary function is activating AMP-activated protein kinase (AMPK), a crucial enzyme in cellular energy homeostasis. AMPK acts as an energy sensor, regulating energy balance by modulating glucose and lipid metabolism. When activated by AICAR, AMPK enhances glucose uptake, fatty acid oxidation, and mitochondrial biogenesis, thus promoting energy production and utilization.