Spatial organization of PI3K-PI(3,4,5)P3-AKT signaling by focal adhesions

Downregulation of PIP4K2C inhibits the breast cancer cell proliferation, migration and invasion

Phosphoinositide signaling pathway has garnered significant attention in recent years due to its implication in metabolic alterations associated with various human diseases, including breast cancer. Phosphatidylinositol-5-phosphate 4-kinase (PIP4K) catalyzes the phosphorylation of phosphatidylinositol-5-phosphate (PI5P) to produce phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2), a lipid that regulates signaling pathways associated with cancer cell growth and metastasis. In breast cancer, PIP4Ks, especially PIP4Kα and PIP4Kβ, have emerged as a significant player, with their dysregulation linked to tumor progression and poor prognosis. However, the role of PIP4Kγ (encoded by PIP4K2C), the other isoform of PIP4K family, remains largely uncharted in breast cancer. Here, we demonstrated that the expression of PIP4K2C is upregulated in breast cancer tissues opposed to the normal tissue utilizing the GTEx and the TCGA public database. The elevation of PIP4K2C expression is further confirmed in the breast cancer cell lines and tissues. Downregulated expression of PIP4K2C by siRNA lowered the subcellular PI(4,5)P2 and suppressed proliferation, migration and invasion of MDA-MB-468, MCF7 breast cancer cell lines. Our research substantiates PIP4K2C as a promising diagnostic and therapeutic biomarker for breast cancer, warranting further investigation into its mechanistic and clinical implications.

Aerobic Exercise and PI3K Inhibitor Ameliorate Obesity Cardiomyopathy by Alleviating Pyroptosis in Middle-Aged Mice

Obesity cardiomyopathy (OCM) represents a rapidly growing health concern globally, characterized by metabolic, structural, and functional abnormalities of the heart. Current research has demonstrated that inflammation plays a pivotal role in obesity-induced cardiomyopathy, and that regular exercise can ameliorate lipid disturbances and inflammatory abnormalities effectively. However, the underlying mechanisms are not fully elucidated. We investigated the effects of an 8-week aerobic exercise intervention on myocardial structure, function, and inflammation in HFD-induced obese mice. The results revealed that aerobic exercise alleviated myocardium pyroptosis and inflammation by down-regulating the PI3K/AKT signaling pathway. Furthermore, the inhibition of the PI3K pathway by LY294002, coupled with exercise, attenuated and suppressed HFD-induced myocardial impairments, inflammation, and pyroptosis, with a synergistic effect. Based on these findings, we concluded that eight weeks of aerobic exercise synergizes with the inhibition of PI3K through inflammatory and pyroptosis mechanisms to improve obesity-associated myocardial remodeling and dysfunction. Therefore, long-term regular aerobic exercise represents a potential strategy in the treatment of OCM.

DNA dioxygenase TET2 deficiency aggravates sepsis-induced acute lung injury by targeting ITGA10 via the PI3K/AKT signaling pathway

BACKGROUND

Sepsis-induced acute lung injury (ALI) is a clinical condition with high morbidity and mortality, and impaired endothelial function is the main pathological characteristic. As a member of DNA demethylases, ten-eleven translocation protein 2 (TET2) is involved in a variety of biological processes. However, the role of TET2 in endothelial dysfunction of sepsis-induced ALI remains unclear.

METHODS

We used cecal ligation and puncture (CLP) to establish a sepsis-induced acute lung injury mouse model and screened out Tet2 from TET family proteins. The results suggested that Tet2 was obviously declined. We used lipopolysaccharide (LPS) to stimulate human pulmonary microvascular endothelial cells (HPMECs) as an in vitro model, and we found the expression of TET2 was also decreased. Then we used small interfering RNAs and adenovirus to knockdown or overexpress TET2 to investigate the effect of TET2 on the function of HPMECs. The changes in sepsis-induced ALI symptoms were also analyzed in Tet2-deficient mice generated by adeno-associated virus 6 (AAV6). Next, RNA sequencing and KEGG analysis were used to find the TET2-regulated downstream target genes and signaling pathways under LPS stimulation. Finally, the rescue experiments were performed to analyze the role of target genes and signaling pathways modulated by TET2 in LPS-treated HPMECs.

RESULTS

TET2 and 5-hmC levels were significantly decreased in both in vitro and in vivo models of sepsis-induced ALI. TET2 knockdown exacerbated the dysfunction and apoptosis of HPMECs induced by LPS. Conversely, TET2 overexpression significantly alleviated these dysfunctions and reduced apoptosis. Meanwhile, the lung injury of Tet2-deficient mice was aggravated by increased inflammation and apoptosis. RNA sequencing and subsequent experiments showed that TET2 overexpression could increase the expression of Integrin α10 (ITGA10) by reducing the methylation level of ITGA10 promoter. This, in turn, activated the PI3K-AKT signaling pathway. Knocking down ITGA10 weakened the beneficial effects of TET2 overexpression in LPS-stimulated endothelial cells.

CONCLUSIONS

In our study, we demonstrated that TET2 deficiency aggravates endothelial cell dysfunction and promotes acute lung injury by targeting ITGA10 via the PI3K-AKT pathway. These findings indicate that TET2 may be a promising therapeutic target for treating sepsis-induced ALI.

Nicotinamide Mononucleotide Alleviates Bile Acid Metabolism and Hormonal Dysregulation in Letrozole-Induced PCOS Mice

Polycystic ovary syndrome (PCOS) involves complex genetic, metabolic, endocrine, and environmental factors. This study explores the effects of nicotinamide mononucleotide (NMN) in a letrozole-induced PCOS mouse model, focusing on metabolic regulation. Letrozole-induced aromatase inhibition elevated androgen and reduced bile acid levels, linking liver dysfunction and gut imbalance to PCOS. Letrozole-treated mice exhibited disrupted estrous cycles, ovarian congestion, and elevated testosterone. NMN intervention alleviated hyperandrogenism, ovarian abnormalities, and bile acid decline but did not fully restore the estrous cycle or improve lipid profiles. Metabolomic analysis showed that NMN partially reversed bile acid and lipid metabolism disturbances. These findings highlight NMN's protective role in reducing hyperandrogenism and ovarian cyst formation. However, effective PCOS treatment should target liver and gut metabolism, not just ovarian symptoms, to mitigate systemic effects. Bile acid dysregulation may play a key role in PCOS progression and warrants further investigation.