Exosomes can transport regulatory biomolecules and are mediators of cellular signaling among metabolic tissues through endocrine mechanisms. Understanding the pathways and processes underlying exosome-mediated inter-tissue communication is critical for elucidating the molecular pathophysiology of metabolic diseases such as obesity, type 2 diabetes mellitus (T2DM), and cardiovascular disorders. Consequently, these mechanisms represent novel and promising targets for pharmacological regulation. We examined the current knowledge regarding exosome physiology, the mechanisms of interaction with target tissues, and its role in metabolic tissue communication. We also analyzed the secretory profiles of exosomes in metabolic tissues, emphasizing their regulatory roles in adipose tissue, liver, pancreas, skeletal muscle, and the small intestine, while discussing their association with metabolic diseases. In this sense, we propose the exosomal pentad as a novel framework highlighting exosome-mediated inter-organ communication, where exosomes may regulate a metabolic axis involving these tissues. This model aligns with the ominous octet in type 2 diabetes but emphasizes exosomes as key regulators of metabolic homeostasis and potential therapeutic targets. The role of exosomes for the treatment of metabolic diseases emerges as a critical area of pharmacologic exploration. For instance, therapeutic strategies that prevent target tissue binding or expression of cargo molecules such as miRNAs could be designed, using antagomiRs or nanoparticles. Additionally, integrins like αvβ5 on the exosomal membrane can be blocked with monoclonal antibodies or engineered for targeted delivery of therapeutic molecules. Exosomes, critical mediators of inter-organ communication and metabolic regulation, hold potential to design precise molecular-level therapies while minimizing systemic side effects.

Resistance to HER2 tyrosine-kinase inhibitor Lapatinib (Lap) is one of the leading causes of cancer treatment failure in HER2+ breast cancer (BC), associated with an aggressive tumor phenotype. Cryptotanshinone (Cry) is a natural terpene molecule that could function as a chemosensitizer by disturbing estrogen receptor (ERα) signaling and inhibiting the protein translation factor-4A, eIF4A. Therefore, we evaluated Cry dual regulation on eIF4A and ERα. This study aimed to elucidate the underlying mechanisms of Lap chemoresistance and the impact of Cry on them. We generated two Lap-resistant BT474 cell HER2+ variants named BT474^LapRV1 and BT474^LapRV2 with high chemoresistance levels, with 7- and 11-fold increases in EC₅₀, respectively, compared to BT474 parental cells. We found a PDCD4-p70S6Kβ axis association with Lap chemoresistance. However, a concomitant down-regulation of the RAF-MEK-ERK cell survival pathway and NF-κB was found in the chemoresistant cell variants; this phenomenon was exacerbated by joint treatment of Cry and Lap under a Lap plasmatic reported concentration. Optimized calcium management was identified as a compensatory mechanism contributing to chemoresistance, as determined by the higher expression of calcium pumps PMCA1/4 and SERCA2. Contrary to expectations, a combination of Lap and Cry did not affect the chemoresistance despite the ERα down-regulation; Cry-eIF4A binding possibly dampens this condition. Results indicated the pro-survival eIF4A/STAT/Bcl-xl pathway and that the down-regulation of the MAPK-NF-κB might function as an adaptive mechanism; this response may be compensated by calcium homeostasis in chemoresistance, highlighting new adaptations in HER2+ cells that lead to chemoresistance.