Pinolenic acid exhibits anti-inflammatory and anti-atherogenic effects in peripheral blood-derived monocytes from patients with rheumatoid arthritis

Abstract

Pinolenic acid (PNLA), an omega-6 polyunsaturated fatty acid from pine nuts, has anti-inflammatory and anti-atherogenic effects. We aimed to investigate the direct anti-inflammatory effect and anti-atherogenic effects of PNLA on activated purified CD14 monocytes from peripheral blood of patients with rheumatoid arthritis (RA) in vitro. Flow cytometry was used to assess the proportions of CD14 monocytes expressing TNF-α, IL-6, IL-1β, and IL-8 in purified monocytes from patients with RA after lipopolysaccharide (LPS) stimulation with/without PNLA pre-treatment. The whole genomic transcriptome (WGT) profile of PNLA-treated, and LPS-activated monocytes from patients with active RA was investigated by RNA-sequencing. PNLA reduced percentage of monocytes expressing cytokines: TNF-α by 23% (p = 0.048), IL-6 by 25% (p = 0.011), IL-1β by 23% (p = 0.050), IL-8 by 20% (p = 0.066). Pathway analysis identified upstream activation of peroxisome proliferator-activated receptors (PPARs), sirtuin3, and let7 miRNA, and KLF15, which are anti-inflammatory and antioxidative. In contrast, DAP3, LIF and STAT3, which are involved in TNF-α, and IL-6 signal transduction, were inhibited. Canonical Pathway analysis showed that PNLA inhibited oxidative phosphorylation (p = 9.14E−09) and mitochondrial dysfunction (p = 4.18E−08), while the sirtuin (SIRTs) signalling pathway was activated (p = 8.89E−06) which interfere with the pathophysiological process of atherosclerosis. Many miRNAs were modulated by PNLA suggesting potential post-transcriptional regulation of metabolic and immune response that has not been described previously. Multiple miRNAs target pyruvate dehydrogenase kinase-4 (PDK4), single-immunoglobulin interleukin-1 receptor molecule (SIGIRR), mitochondrially encoded ATP synthase membrane subunit 6 (MT-ATP6) and acetyl-CoA acyltranferase2 (ACAA2); genes implicated in regulation of lipid and cell metabolism, inflammation, and mitochondrial dysfunction. PNLA has potential anti-atherogenic and immune-metabolic effects on monocytes that are pathogenic in RA and atherosclerosis. Dietary PNLA supplementation regulates key miRNAs that are involved in metabolic, mitochondrial, and inflammatory pathways.

The Beneficial Effects of Pine Nuts and Its Major Fatty Acid, Pinolenic Acid, on Inflammation and Metabolic Perturbations in Inflammatory Disorders

“…Adipocyte function, glucose metabolism, insulin secretion signalling pathways, CCK secretion, mitochondrial ATP synthase, the NAD signalling pathway, and FA β-oxidation were among the metabolic signalling pathways identified. Ten miRNAs target PDK4, which controls TNF-α and NF-κB [5,88]; miR-3173, miR-2861, miR-626, miR-28, miR-7150, miR-3188, miR-879-5p, miR-393-5p, miR-708-5p, and miR-12118 [6]. Cellular metabolism depends on PDK4, and PDK4 deficiencies result in the death of hepatocytes by apoptosis with an increase in mitochondrial numbers, ROS production, prolonged activation of c-Jun N-terminal kinase (JNK), and decreased glutathione levels.…”

“…Some PUFAs such as PNLA are examples of nutraceuticals which are believed to have anti-inflammatory effects through intracellular signals that activate anti-inflammatory pathways, such as peroxisome proliferator-activated receptors (PPARs) [ 4 , 5 , 6 ], and suppress pro-inflammatory pathways/mediators such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) [ 5 , 6 ], arachidonic acid (AA)-derived eicosanoids, and reactive oxygen species (ROS) generation with generally an excellent safety profile [ 3 , 4 , 5 , 6 ]. Amr and Abeer showed that pine nuts oil (PNO) possesses a wide therapeutic effect, such as antibacterial, antifungal, antiviral, antiseptic, expectorant, cholagogue, choleretic, diuretic, and antihypertensive [ 7 ].…”

“…Amr and Abeer showed that pine nuts oil (PNO) possesses a wide therapeutic effect, such as antibacterial, antifungal, antiviral, antiseptic, expectorant, cholagogue, choleretic, diuretic, and antihypertensive [ 7 ]. In human studies, PNLA has been demonstrated to have anti-inflammatory, immune-metabolic, anti-rheumatic and anti-atherogenic actions [ 5 , 6 ] together with weight-lowering properties [ 2 ]. According to many studies, PNO and PNLA have the potential to be used as anti-cholesteric agents [ 3 , 7 , 8 ].…”

“…Key down-regulated and up-regulated miRNAs in PNLA treated, LPS-stimulated versus vehicle treated LPS-stimulated CD14 monocytes from patients with RA. "Adapted with permission from Takala et al[6]. Copyright 2022, Scientific Reports".…”

“…Selected miRNAs target specific mRNAs and the signalling pathways that they are linked to, according to the Ingenuity pathway Analysis (IPA) database. "Adapted with permission from Takala et al[6]. Copyright 2022, Scientific Reports".…”