Inter-Organ Communication Beyond Mammals: The Role of Tissue-Specific Cytokines

Adipose tissue is no longer considered to be merely energy storage, but instead a key endocrine organ controlling metabolism and homeostasis. Indeed, adipose tissue secretes many cytokines (i.e., adipokines) such as leptin and adiponectin that act locally but also interact with other tissues. Similarly, although bone and skeletal muscle have been traditionally viewed in the context of locomotion, these organs also communicate through the endocrine system regulating metabolism. This crosstalk is orchestrated by a family of cytokines, namely myokines (e.g., IL6, irisin or myostatin) and osteokines (e.g., osteocalcin). In addition, some of these peripheral cytokines can have important neuroendocrine roles; for example, leptin and lipocalin 2 (an osteokine), which act in the hypothalamus regulating appetite. Up to now many of these crosstalks and the cytokines involved have been primarily described in mammals. Thus, we would like to pay special attention to inter-organ communication in non-mammalian species.

The recent revelations of the role of adipose tissue, skeletal muscle, and bone as endocrine organs has revolutionized the concept of integration among tissues. However, further investigation on the biological mechanisms underlying these physiological interactions beyond mammals is required. This Research Topic aims to address the directional effects of adipokines, myokines, and osteokines, and the impact of their crosstalk on growth and whole-body metabolic homeostasis. Moreover, to highlight the role of cytokines during specific energy-demanding conditions such as exercise, fasting, and in the manifestation of various age- and metabolically related diseases like obesity or sarcopenia. The goal is to cover promising and novel research trends in the field of inter-organ communication in health and disease in model organisms or farmed species, but not excluding humans or other mammalian species.

In this Research Topic, we welcome authors to contribute original research articles as well as review articles or mini reviews focused on tissue crosstalk mediated by cytokines. Areas to be covered may include, but are not limited to:
• Identification and characterization of novel tissue-specific cytokines
• The endocrine/paracrine roles of specific cytokines and their mechanism of action
• Crosstalk between bone and skeletal muscle controlling growth and metabolism
• Effects of adipokines or osteokines on muscle during exercise
• Crosstalk between peripheral tissues in health and disease
• Neuroendocrine modulation of appetite and whole-body energy homeostasis

**Cover image created by Esmail Lutfi with BioRender.com