Mycoplasma pneumoniae (M. pneumoniae, Mp) is an intracellular pathogen that causes pneumonia, tracheobronchitis, pharyngitis, and asthma in humans and can infect and survive in the host cells leading to excessive immune responses. Extracellular vesicles (EVs) from host cells carry components of pathogens to recipient cells and play a role in intercellular communication during infection. However, there is limited knowledge on whether EVs derived from M. pneumoniae-infected macrophages play as intercellular messengers and functional mechanisms. In this study, we establish a cell model of M. pneumoniae-infected macrophages that continuously secrete EVs to further asses their role as intercellular messengers and their functional mechanisms. Based on this model, we determined a method for isolating the pure EVs from M. pneumoniae-infected macrophages, which employs a sequence of operations, including differential centrifugation, filtering, and ultracentrifugation. We identified EVs and their purity using multiple methods, including electron microscopy, nanoparticle tracking analysis, Western blot, bacteria culture, and nucleic acid detection. EVs from M. pneumoniae-infected macrophages are pure, with a 30–200 nm diameter. These EVs can be taken up by uninfected macrophages and induce the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 through the nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) signals pathway. Moreover, the expression of inflammatory cytokines induced by EVs relies on TLR2-NF-κB/JNK signal pathways. These findings will help us better understand a persistent inflammatory response and cell-to-cell immune modulation in the context of M. pneumoniae infection.

Cancer cells frequently alter their metabolism to support biogenesis and proliferation and survive specific metabolic stressors. The glucose-associated pentose phosphate pathway (PPP) is crucial for cancer cell proliferation. In particular, 6-phosphogluconate dehydrogenase (6PGD), the second dehydrogenase in the PPP, catalyzes the decarboxylation of 6-phosphogluconate into ribulose 5-phosphate (Ru5P). However, the mechanisms controlling 6PGD expression in cancer cells remain unclear. Herein, we show that TAp73 increases Ru5P and NADPH production through 6PGD activation to counteract reactive oxygen species and protects cells from apoptosis. Moreover, 6PGD overexpression rescues the proliferation and tumorigenic ability of TAp73-deficient cells. These findings further establish the critical role of TAp73 on glucose metabolism regulation, demonstrating that TAp73 can activate 6PGD expression to support oncogenic cell growth. Implications: By transcriptional upregulation of 6PGD, TAp73 promotes the generation of Ru5P and NADPH, and enhances tumor cell proliferation.

The role of long non-coding RNA (lncRNAs) in biological processes remains poorly understood, despite their significant impact. Our previous research discovered that the expression of AL137782.1, a long transcript of the novel lncRNA ENSG00000261553, is upregulated in lung epithelial cells upon exposure to microbes. Furthermore, the expression of AL137782.1 exhibits variability between para-cancerous and lung adenocarcinoma samples. These findings imply that this lncRNA may play a role in both normal lung epithelial cellular processes and pathophysiology. To elucidate the function of AL137782.1 in lung epithelial cells, we utilized bioinformatics retrieval and analysis to examine its expression. We then analyzed its subcellular localization using fluorescence in situ hybridization (FISH) and subcellular fractionation. Through rapid amplification of cDNA ends (RACE), we confirmed the presence of a 4401 nt lncRNA AL137782.1 in lung epithelial cells. Moreover, we discovered that this lncRNA positively regulates both mRNA and the protein expression of LMO7, a protein that may regulate the cell migration of normal lung epithelial cells. Although the overexpression of AL137782.1 has been shown to enhance the migration of both normal lung epithelial cells and lung adenocarcinoma cells in vitro, our study revealed that the expression of this lncRNA was significantly decreased in lung cancers compared to adjacent tissues. This suggests that the cell migration pattern regulated by the AL137782.1–LMO7 axis is more likely to occur in normal lung epithelial cells, rather than being a pathway that promotes lung cancer cell migration. Therefore, our study provides new insights into the mechanism underlying cell migration in human lung epithelial cells. This finding may offer a potential strategy to enhance normal lung epithelial cell migration after lung injury.

Chronic nonprogressive pneumonia is a prevalent disease that infects many young sheep. Mycoplasma ovipneumoniae was isolated from the lungs of sheep with chronic nonprogressive pneumonia. Evidences showed that it might associate with the development and duration of chronic pneumonia, moreover, sheep infected with M. ovipneumoniae are easily infected by other organisms, suggesting that M. ovipneumoniae may play an immunosuppressive role during infection. However, the mechanism is still poorly understood. The infection occurs in the airway, where resident alveolar macrophages first encounter M. ovipneumoniae . Therefore, primary alveolar macrophages (AMs) were collected from the lungs of healthy adult sheep, and the (iTRAQ) protein assay was used to investigate the immunosuppressive effects of M. ovipneumoniae on sheep AMs. The RAW264.7 cells were used to confirm the findings. The results showed that M. ovipneumoniae promoted higher expression of anti-apoptotic proteins and lower expression of apoptosis-related proteins in the infected AMs. Moreover, the number of infected AMs increased. However, M. ovipneumoniae reduced ATP levels in AMs and impaired late endosome maturation and phagolysosome fusion. Furthermore, M. ovipneumoniae inhibited the autophagy pathway via the Akt-mTOR axis in AMs. These findings indicated that M. ovipneumoniae had distinctive strategies to evade elimination caused by the AMs. The findings might explain the chronic infection and co-infection in sheep infected by M. ovipneumoniae .

Stem cells are crucial for maintaining bodily stability, but their regenerative abilities decline with age. This decline is marked by reduced proliferation and differentiation capacities of stem cells, as well as exhaustion of the stem cell pool. The accumulation of aged mesenchymal stem cells (MSCs) can reduce the tissue regeneration, but the molecular mechanisms influencing MSCs aging remain unclear. Moreover, collecting MSCs from elderly individuals is not suitable for observing the early response of MSCs to senescence stress, and the factors involved in early senescence remain unclear. In our previous study, we established a fast MSC aging model using D-galactose. We discovered that, while not affecting the "stemness" markers of mesenchymal stem cells, the expression of LncRNA NEAT1-206 was notably increased during the early stages of aging induction (within 4 days). And LncRNA NEAT1-206 was observed to be localized in the cytoplasmic matrix due to enhanced nuclear export. We found that the LncRNA NEAT1-206 could trigger autophagy through the WNT5A/Ca²⁺ signaling pathway, thereby decreasing senescence markers and enhancing the osteogenic differentiation of MSCs. This study elucidated the role that LncRNA NEAT1-206 as a potential key factor in conferring resistance to D-galactose-induced cell senescence at the early stage and promoting the osteogenic differentiation of MSCs. This study may provide a foundational understanding for delaying the MSCs aging process.

S1. TAp73 activates the expression of 6PGD