Edible blue-green algae reduce the production of pro-inflammatory cytokines by inhibiting NF-κB pathway in macrophages and splenocytes

Abstract

Background Chronic inflammation contributes to the development of pathological disorders including insulin resistance and atherosclerosis. Identification of anti-inflammatory natural products can prevent the inflammatory diseases. Methods Anti-inflammatory effects of blue-green algae (BGA), i.e., Nostoc commune var. Sphaeroides Kützing (NO) and Spirulina Platensis (SP), were compared in RAW 264.7 and mouse bone marrow-derived macrophages (BMM) as well as splenocytes from apolipoprotein E knockout (apoE−/−) mice fed BGA. Results When macrophages pretreated with 100 μg/ml NO lipid extract (NOE) or SP lipid extract (SPE) were activated by lipopolysaccharide (LPS), expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), and IL-6, were significantly repressed. NOE and SPE also significantly repressed the expression of TNFα and IL-1β in BMM. LPS-induced secretion of IL-6 was lower in splenocytes from apoE−/− fed an atherogenic diet containing 5% NO or SP for 12 weeks. In RAW 264.7 macrophages, NOE and SPE markedly decreased nuclear translocation of NF-κB. The degree of repression of pro-inflammatory gene expression by algal extracts was much stronger than that of SN50, an inhibitor of NF-κB nuclear translocation. Trichostatin A, a pan histone deacetylase inhibitor, increased basal expression of IL-1β and attenuated the repression of the gene expression by SPE. SPE significantly down-regulated mRNA abundance of 11 HDAC isoforms, consequently increasing acetylated histone 3 levels. Conclusion NOE and SPE repress pro-inflammatory cytokine expression and secretion in macrophages and splenocytes via inhibition of NF-κB pathway. Histone acetylation state is likely involved in the inhibition. General significance This study underscores natural products can exert anti-inflammatory effects by epigenetic modifications such as histone acetylation.

Protective Effects of Honey and Spirulina Platensis on Acetic Acid-Induced Ulcerative Colitis in Rats

“…NF-κB induces proinflammatory gene expression under oxidative stress and inflammatory conditions and increases cytokine production (e.g. interleukins, TNF-α, COX-2, and iNOS) (14).…”

Astaxanthin prevents TGFβ1-induced pro-fibrogenic gene expression by inhibiting Smad3 activation in hepatic stellate cells

“…β-Tubulin (Santa Cruz Biotechnology, Santa Cruz, CA) or β-actin (Sigma, St. Louis, MO) was used as a loading control. For Western blot of nuclear and cytoplasmic cell fractions, the fractions were prepared using a nuclear extraction kit (Cayman, Ann Arbor, MI) as we previously described [33]. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) (Santa Cruz Biotechnology, Santa Cruz, CA) and lamin B (Santa Cruz Biotechnology) were used as a loading control for cytoplasmic and nuclear fractions, respectively.…”

In Vitro Cytotoxicity and Antioxidative Potential of Nostoc Microscopicum (Nostocales, Cyanobacteria)

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