Adiponectin, an adipocyte-derived hormone, was recently shown to have potential therapeutic applications in diabetes and obesity because of its influence on glucose and lipid metabolism. We found that brown fat in normal human bone marrow contains this protein and used marrow-derived preadipocyte lines and long-term cultures to explore potential roles in hematopoiesis. Recombinant adiponectin blocked fat cell formation in long-term bone marrow cultures and inhibited the differentiation of cloned stromal preadipocytes. Adiponectin also caused elevated expression of cyclooxygenase-2 (COX-2) by these stromal cells and induced release of prostaglandin E2 (PGE2). The COX-2 inhibitor Dup-697 prevented the inhibitory action of adiponectin on preadipocyte differentiation, suggesting involvement of stromal cell–derived prostanoids. Furthermore, adiponectin failed to block fat cell generation when bone marrow cells were derived from B6,129SPtgs2tm1Jed (COX-2+/–) mice. These observations show that preadipocytes represent direct targets for adiponectin action, establishing a paracrine negative feedback loop for fat regulation. They also link adiponectin to the COX-2–dependent PGs that are critical in this process.
Takafumi Yokota, C.S. Reddy Meka, Kay L. Medina, Hideya Igarashi, Phillip C. Comp, Masahiko Takahashi, Makoto Nishida, Kenji Oritani, Jun-ichiro Miyagawa, Tohru Funahashi, Yoshiaki Tomiyama, Yuji Matsuzawa, Paul W. Kincade
Usage data is cumulative from February 2019 through February 2020.
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.