Desmosterol: A natural product derived from macroalgae modulates inflammatory response and oxidative stress pathways in intestinal epithelial cells

Goat milk derived small extracellular vesicles ameliorate LPS-induced intestinal epithelial barrier dysfunction, oxidative stress, and apoptosis by inhibiting the MAPK signaling pathway

Intestinal injury is often accompanied by epithelial barrier dysfunction, oxidative stress, and apoptosis. Previous research studies have demonstrated that small extracellular vesicles (sEVs) from animal milk play a crucial role in regulating intestinal injury. Nonetheless, there has been limited research on the impact of goat milk sEVs on intestinal damage. This study aims to explore the functional differences between proteins in colostrum-derived sEVs (CME) and mature milk-derived sEVs (MME) from goat and elucidate their effects and mechanisms on lipopolysaccharide (LPS)-induced injury in IEC-6. Proteomic analysis revealed that both CME and MME are rich in various bioactive proteins that have regulatory effects on cell damage. CME and MME significantly improved LPS-induced IEC-6 barrier dysfunction and oxidative stress. Additionally, CME and MME alleviated LPS-induced IEC-6 proliferation inhibition and apoptosis. Notably, CME exhibited a more significant improvement effect. RNA-Seq analysis indicated that CME ameliorates IEC-6 injury by inhibiting multiple genes and signaling pathways associated with cell damage, particularly the MAPK signaling pathway. In summary, goat milk-derived sEVs improve LPS-induced IEC-6 injury by targeting the MAPK signaling pathway, significantly restoring the intestinal epithelial barrier function, reducing oxidative stress, and alleviating apoptosis. These findings offer scientific evidence supporting the potential application of goat milk-derived sEVs as protective agents against intestinal injury.

Desmosterol-driven atypical macrophage polarization regulates podocyte dynamics in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) stands as a leading diabetes complication, with macrophages intricately involved in its evolution. While glucose metabolism's impact on macrophage activity is well-established, cholesterol metabolism's contributions remain less explored. Our study seeks to elucidate this association.

METHODS AND RESULTS

Methods and Results: Gene expression analysis of monocytes from the blood of both normal and diabetic patients was conducted using public databases, showing that cholesterol metabolism pathways, especially Bloch and Kandutsch-Russell, were more altered in diabetic monocytes/macrophages than glucose-responsive pathways. When bone marrow-derived macrophages (BMDMs) were subjected to desmosterol, they exhibited an unconventional polarization. These BMDMs displayed heightened levels of both M1-related pro-inflammatory cytokines and M2-linked anti-inflammatory factors. Further, in co-culture, desmosterol-conditioned BMDMs paralleled M2 macrophages in augmenting Ki-67 + podocyte populations while mimicking M1 macrophages in elevating TUNEL + apoptotic podocytes. Comparable outcomes on podocytes were obtained using conditioned media from the respective BMDMs.

CONCLUSIONS

Our data underscores the pivotal role of cholesterol metabolism, particularly via desmosterol, in steering macrophages toward an unconventional polarization marked by both inflammatory and regulatory traits. Such unique macrophage behavior concurrently impacts podocyte proliferation and apoptosis, shedding fresh light on DN pathogenesis and hinting at potential therapeutic interventions.