ETS1 deficiency in macrophages suppresses colorectal cancer progression by reducing the F4/80+TIM4+ macrophage population.

Tumor-associated macrophages (TAMs) take on pivotal and complex roles in the tumor microenvironment (TME); however, their heterogeneity in the TME remains incompletely understood. ETS proto-oncogene 1 (ETS1) is a transcription factor that is mainly expressed in lymphocytes. However, its expression and immunoregulatory role in colorectal cancer (CRC)-associated macrophages remain unclear. In the study, the expression levels of ETS1 in CD68+ macrophages in the CRC microenvironment were significantly higher than those in matched paracarcinoma tissues. Importantly, ETS1 increased the levels of chemokines C-C motif chemokine ligand 2 (CCL2) and C-X-C motif chemokine ligand 10 (CXCL10) in lipopolysaccharide-stimulated THP-1 cells. It also boosted the migration and invasion of CRC cells during the in vitro co-culture. In the ETS1 conditional knockout mouse model, ETS1 deficiency in macrophages ameliorated the histological changes in DSS-induced ulcerative colitis mouse models and prolonged the survival in an azomethane/dextran sodium sulfate (AOM/DSS)-induced CRC model. ETS1 deficiency in macrophages substantially inhibited tumor formation, reduced F4/80+TIM4+ macrophages in the mesenteric lymph nodes, and decreased CCL2 and CXCL10 protein levels in tumor tissues. Moreover, ETS1 deficiency in macrophages effectively prevented liver metastasis of CRC and reduced the infiltration of TAMs into the metastasis sites. Subsequent studies have indicated that ETS1 upregulated the expression of T-cell immunoglobulin mucin receptor 4 in macrophages through the signal transducer and activator of the transcription 1 signaling pathway activated by the autocrine action of CCL2/CXCL10. Collectively, ETS1 deficiency in macrophages potentiates antitumor immune responses by repressing CCL2 and CXCL10 expression, shedding light on potential therapeutic strategies for CRC.

Exploration of Catalytic Selectivity for Aminotransferase (BtrR) Based on Multiple Molecular Dynamics Simulations.

The aminotransferase from Bacillus circulans (BtrR), which is involved in the biosynthesis of butirosin, catalyzes the pyridoxal phosphate (PLP)-dependent transamination reaction to convert valienone to ß-valienamine (a new ß-glycosidase inhibitor for the treatment of lysosomal storage diseases) with an optical purity enantiomeric excess value. To explore the stereoselective mechanism of valienamine generated by BtrR, multiple molecular dynamics (MD) simulations were performed for the BtrR/PLP/valienamine and BtrR/PLP/ß-valienamine complexes. The theoretical results showed that ß-valienamine could make BtrR more stable and dense than valienamine. ß-valienamine could increase the hydrogen bond probability and decrease the binding free energy between coenzyme PLP and BtrR by regulating the protein structure of BtrR, which was conducive to the catalytic reaction. ß-valienamine maintained the formation of cation-p interactions between basic and aromatic amino acids in BtrR, thus enhancing its stability and catalytic activity. In addition, CAVER 3.0 analysis revealed that ß-valienamine could make the tunnel of BtrR wider and straight, which was propitious to the removal of products from BtrR. Steered MD simulation results showed that valienamine interacted with more residues in the tunnel during dissociation compared with ß-valienamine, resulting in the need for a stronger force to be acquired from BtrR. Taken together, BtrR was more inclined to catalyze the substrates to form ß-valienamine, either from the point of view of the catalytic reaction or product removal.

Mitochondrial activity related genes of mast cells identify poor prognosis and metastasis of ovarian cancer.

The pro-tumorigenic or anti-tumorigenic role of tumor infiltrating mast cells (TIMs) in tumors depends not only on the type of cancer and the degree of tumor progression, but also on their location in the tumor bulk. In our investigation, we employed immunohistochemistry to reveal that the mast cells (MCs) in the tumor stroma are positively correlated with metastasis of ovarian cancer (OC), but not in the tumor parenchyma. To delve deeper into the influence of different culture matrix stiffness on MCs' biological functions within the tumor parenchymal and stromal regions, we conducted a transcriptome analysis of the mouse MC line (P815) cultured in two-dimensional (2D) or three-dimensional (3D) culture system. Further research has found that the softer 3D extracellular matrix stiffness could improve the mitochondrial activity of MCs to promote proliferation by increasing the expression levels of mitochondrial activity-related genes, namely Pet100, atp5md, and Cox7a2. Furthermore, employing LASSO regression analysis, we identified that Pet100 and Cox7a2 were closely associated with the prognosis of OC patients. These two genes were subsequently employed to construct a risk score model, which revealed that the high-risk group model as one of the prognostic factors for OC patients. Additionally, the XCell algorithm analysis showed that the high-risk group displayed a broader spectrum of immune cell infiltrations. Our research revealed that TIMs in the tumor stroma could promote the metastasis of OC, and mitochondrial activity-related proteins Pet100/Cox7a2 can serve as biomarkers for prognostic evaluation of OC.

Cell sheet formation enhances the therapeutic effects of adipose-derived stromal vascular fraction on urethral stricture.

Urethral stricture (US) is a common disease in urology, lacking effective treatment options. Although injecting a stem cells suspension into the affected area has shown therapeutic benefits, challenges such as low retention rate and limited efficacy hinder the clinical application of stem cells. This study evaluates the therapeutic impact and the mechanism of adipose-derived vascular fraction (SVF) combined with cell sheet engineering technique on urethral fibrosis in a rat model of US. The results showed that SVF-cell sheets exhibit positive expression of α-SMA, CD31, CD34, Stro-1, and eNOS. In vivo study showed less collagen deposition, low urethral fibrosis, and minimal tissue alteration in the group receiving cell sheet transplantation. Furthermore, the formation of a three-dimensional (3D) tissue-like structure by the cell sheets enhances the paracrine effect of SVF, facilitates the infiltration of M2 macrophages, and suppresses the TGF-ß/Smad2 pathway through HGF secretion, thereby exerting antifibrotic effects. Small animal in vivo imaging demonstrates improved retention of SVF cells at the damaged urethra site with cell sheet application. Our results suggest that SVF combined with cell sheet technology more efficiently inhibits the early stages of urethral fibrosis.

FSTL3 promotes tumor immune evasion and attenuates response to anti-PD1 therapy by stabilizing c-Myc in colorectal cancer.

Programmed cell death 1 ligand 1 (PDL1)/programmed cell death 1 (PD1) blockade immunotherapy provides a prospective strategy for the treatment of colorectal cancer (CRC), but various constraints on the effectiveness of the treatment are still remaining. As reported in previous studies, follistatin-like 3 (FSTL3) could mediate inflammatory response in macrophages by induction lipid accumulation. Herein, we revealed that FSTL3 were overexpressed in malignant cells in the CRC microenvironment, notably, the expression level of FSTL3 was related to tumor immune evasion and the clinical efficacy of anti-PD1 therapy. Further studies determined that hypoxic tumor microenvironment induced the FSTL3 expression via HIF1α in CRC cells, FSTL3 could bind to the transcription factor c-Myc (354-406 amino acids) to suppress the latter's ubiquitination and increase its stability, thereby to up-regulated the expression of PDL1 and indoleamine 2,3-dioxygenase 1 (IDO1). The results in the immunocompetent tumor models verified that FSLT3 knockout in tumor cells increased the proportion of CD8+ T cells in the tumor microenvironment, reduced the proportion of regulatory T cells (CD25+ Foxp3+) and exhausted T cells (PD1+ CD8+), and synergistically improved the anti-PD1 therapy efficacy. To sum up, FSTL3 enhanced c-Myc-mediated transcriptional regulation to promote immune evasion and attenuates response to anti-PD1 therapy in CRC, suggesting the potential of FSTL3 as a biomarker of immunotherapeutic efficacy as well as a novel immunotherapeutic target in CRC.

Co-evolution of tRNA 3' trailer sequences with 3' processing enzymes in bacteria.

Maturation of the tRNA 3' terminus is a complicated process in bacteria. Usually, it is initiated by an endonucleolytic cleavage carried out by RNase E and Z in different bacteria. In Escherichia coli, RNase E cleaves AU-rich sequences downstream of tRNA, producing processing intermediates with a few extra residues at the 3' end; these are then removed by exoribonuclease trimming to generate the mature 3' end. Here we show that essentially all E. coli tRNA precursors contain a potential RNase E cleavage site, the AU-rich sequence element (AUE), in the 3' trailer. This suggests that RNase E cleavage and exonucleolytic trimming is a general pathway for tRNA maturation in this organism. Remarkably, the AUE immediately downstream of each tRNA is selectively conserved in bacteria having RNase E and tRNA-specific exoribonucleases, suggesting that this pathway for tRNA processing is also commonly used in these bacteria. Two types of RNase E-like proteins are identified in actinobacteria and the alpha-subdivision of proteobacteria. The tRNA 3' proximal AUE is conserved in bacteria with only one type of E-like protein. Selective conservation of the AUE is usually not observed in bacteria without RNase E. These results demonstrate a novel example of co-evolution of RNA sequences with processing activities.