Irisin: A true, circulating hormone

Polyzos, Stergios A.; Mathew, Hannah; Mantzoros, Christos S.

doi:10.1016/j.metabol.2015.09.001

Cited by 53 publications

(30 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Currently, there is no consensus regarding the physiological range of circulating irisin during rest and exercise (2,17). Estimates vary from 5 to 1,200 ng/ml in different settings using commercial ELISA kits (12,31). A recent study examined these ELISA kits and discovered that they lack specificity, casting doubt on the previous measurements of circulating irisin levels (2).…”

Section: Discussionmentioning

confidence: 99%

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes

Zhang

Xie

Wang

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

158

100

View full text Add to dashboard Cite

To better understand the role of irisin in humans, we examined the effects of irisin in human primary adipocytes and fresh human subcutaneous white adipose tissue (scWAT). Human primary adipocytes derived from 28 female donors' fresh scWAT were used to examine the effects of irisin on browning and mitochondrial respiration, and preadipocytes were used to examine the effects of irisin on adipogenesis and osteogenesis. Cultured fragments of scWAT and perirenal brown fat were used for investigating signal transduction pathways that mediate irisin's browning effect by Western blotting to detect phosphorylated forms of p38, ERK, and STAT3 as well as uncoupling protein 1 (UCP1). Individual responses to irisin in scWAT were correlated with basal expression levels of brown/beige genes. Irisin upregulated the expression of browning-associated genes and UCP1 protein in both cultured primary mature adipocytes and fresh adipose tissues. It also significantly increased thermogenesis at 5 nmol/l by elevating cellular energy metabolism (OCR and ECAR). Treating human scWAT with irisin increased UCP1 expression by activating the ERK and p38 MAPK signaling. Blocking either pathway with specific inhibitors abolished irisin-induced UCP1 upregulation. However, our results showed that UCP1 in human perirenal adipose tissue was insensitive to irisin. Basal levels of brown/beige and FNDC5 genes correlated positively with the browning response of scWAT to irisin. In addition, irisin significantly inhibited adipogenic differentiation but promoted osteogenic differentiation. We conclude that irisin promotes "browning" of mature white adipocytes by increasing cellular thermogenesis, whereas it inhibits adipogenesis and promotes osteogenesis during lineage-specific differentiation. Our findings provide a rationale for further exploring the therapeutic use of irisin in obesity and exercise-associated bone formation.

show abstract

Section: Discussionmentioning

confidence: 99%

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes

Zhang

Xie

Wang

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

158

100

View full text Add to dashboard Cite

show abstract

“…Circulating irisin is removed from the body mainly through the hepatobiliary system and the kidneys 14 . The reported circulating levels of irisin seem to differ greatly even in the same species, with concentrations being reported in human serum or plasma between 0.01 ng/ml and 2,000 ng/ml (REFS 15–19). These inconsistencies have raised doubts about the validity of the different assays and even about the actual existence of irisin in humans 15–20 .…”

Section: Physiology Of Irisinmentioning

confidence: 99%

Physiology and role of irisin in glucose homeostasis

et al. 2017

Self Cite

View full text Add to dashboard Cite

Irisin is a myokine that leads to increased energy expenditure by stimulating the ‘browning’ of white adipose tissue. In the first description of this hormone, increased levels of circulating irisin, which is cleaved from its precursor fibronectin type III domain-containing protein 5, were associated with improved glucose homeostasis by reducing insulin resistance. Consequently, several studies attempted to characterize the role of irisin in glucose regulation, but contradictory results have been reported, and even the existence of this hormone has been questioned. In this Review, we present the current knowledge on the physiology of irisin and its role in glucose homeostasis. We describe the mechanisms involved in the synthesis, secretion, circulation and regulation of irisin, and the controversies regarding the measurement of irisin. We also discuss the direct effects of irisin on glucose regulatory mechanisms in different organs, the indirect effects and interactions with other hormones, and the important open questions with regard to irisin in those organs. Finally, we present the results from animal interventional studies and from human clinical studies investigating the association of irisin with obesity, insulin resistance, type 2 diabetes mellitus and the metabolic syndrome.

show abstract

“…Therefore, moderate increases in irisin produces an improvement in IR within the diet induced changes. This property candidates irisin as a potential therapeutic target in metabolic diseases, including metabolic syndrome, T2DM, and nonalcoholic fatty liver disease (NAFLD), in which IR plays a major pathogenic role [ 143 ]. Additionally, irisin may promote pancreatic β-cells survival and improve glucose-induced insulin secretion under lipotoxic conditions [ 58 ] or high glucose state [ 144 ].…”

Section: Fndc5/irisin and Autophagymentioning

confidence: 99%

Irisin and Autophagy: First Update

Pesce

Ballerini

Paolucci

et al. 2020

IJMS

View full text Add to dashboard Cite

Aging and sedentary life style are considered independent risk factors for many disorders. Under these conditions, accumulation of dysfunctional and damaged cellular proteins and organelles occurs, resulting in a cellular degeneration and cell death. Autophagy is a conserved recycling pathway responsible for the degradation, then turnover of cellular proteins and organelles. This process is a part of the molecular underpinnings by which exercise promotes healthy aging and mitigate age-related pathologies. Irisin is a myokine released during physical activity and acts as a link between muscles and other tissues and organs. Its main beneficial function is the change of subcutaneous and visceral adipose tissue into brown adipose tissue, with a consequential increase in thermogenesis. Irisin modulates metabolic processes, acting on glucose homeostasis, reduces systemic inflammation, maintains the balance between resorption and bone formation, and regulates the functioning of the nervous system. Recently, some of its pleiotropic and favorable properties have been attributed to autophagy induction, posing irisin as an important regulator of autophagy by exercise. This review article proposes to bring together for the first time the “state of the art” knowledge regarding the effects of irisin and autophagy. Furthermore, treatments on relation between exercise/myokines and autophagy have been also achieved.

show abstract

Irisin: A true, circulating hormone

Cited by 53 publications

References 33 publications

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes

Physiology and role of irisin in glucose homeostasis

Irisin and Autophagy: First Update

Contact Info

Product

Resources

About