Project description:Ischemic stroke (IS) is one of the most serious neurological diseases, characterized by high mortality and disability rates. Glia cells, particularly microglia and astrocytes, occupy a pivotal position in the progression of IS. In response to stroke, microglia undergo polarization, transforming into either pro-inflammatory M1 phenotype or anti-inflammatory M2 phenotype. Analogously, astrocytes would polarize to pro-inflammatory A1 phenotype or anti-inflammatory A2 phenotype. It has been documented that A1 astrocytes can be activated by M1 microglia, although precise underlying mechanism remains elusive. In our study, we emulated ischemic injury using a middle cerebral artery occlusion/reperfusion (MCAO/R) model in mice and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in primary astrocytes. Our findings revealed that M1 microglia could activate A1 astrocytes by secreting exosomes. According to RNA sequencing, circSTRN3 was enriched in M1 microglia-derived exosomes. Based on the review of literature and bioinformatics analysis, it was suggested that circSTRN3 could sponge miR-331-5p, while miR-331-5p could bind to MAVS and participate in the activation of NF-kB pathway and A1 astrocytes. Western blotting and qRT-PCR experiments verified this process. Furtherly, overexpression of circSTRN3 could aggravate neurological deficits, increase infarct volume, and promote cell death in MCAO/R model, whereas miR-331-5p inhibited this process. Furthermore, we conducted tests on circSTRN3 and miR-331-5p in exosomes isolated from the peripheral blood of IS patients, thereby confirming the correlation among circSTRN3, miR-331-5p, and the stroke severity score. Taken together, our study indicated that M1 microglia-derived exosomes could promote A1 astrocyte activation and exacerbate ischemic brain injury through the circSTRN3-miR331-5P/MAVS/NF-KB pathway.
Project description:Metastasis is the key determinant of poor prognosis for advanced-stage NSCLC patients. Although an important contributor to metastasis is cross-talk between tumor-associated macrophages (TAMs) and tumor cells, its regulation is not fully understood. Expressed primarily in macrophages, scavenger receptor A1 (SR-A1) has been associated with lung tumorigenesis. Here, the mechanistic basis for the involvement of SR-A1 in lung cancer prognosis was investigated using population genetics, transcriptomics, and functional analyses. SR-A1 genetic variants were investigated for possible association with survival of advanced-stage NSCLC patients in the Harvard Lung Cancer Study cohort. Two SNPs (rs17484273, rs1484751) in SR-A1 were significantly associated with poor overall survival of NSCLC patients. Further, data from The Cancer Genome Atlas showed a considerable down-regulation of SR-A1 in lung tumor tissues. The association of SR-A1 with prognosis was validated in animal models in the context of lung cancer metastasis. Macrophages derived from SR-A1 knockout mice accelerated metastasis in a lung cancer mouse model. On the other hand, tumor cell seeding, migration, and invasion as well as macrophage accumulation in lung cancer tissue were enhanced in SR-A1 knockout mice. Furthermore, SR-A1 deficiency promoted up-regulation of serum amyloid A1 (SAA1) in macrophages, which appeared to be mediated by MAPK/Ikappa-B/NF-kappaB signaling. Further, SAA1 exposure promoted tumor cell invasion and macrophage migration in vitro and in vivo, but these effects were blocked by administration of an anti-SAA1 antibody. These findings suggest that SR-A1 may suppress lung cancer metastasis by down-regulating SAA1 production in macrophages.
Project description:Primary objectives: The primary objective is to investigate circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).
Primary endpoints: circulating tumor DNA (ctDNA) via deep sequencing for mutation detection and by whole genome sequencing for copy number analyses before start (baseline) with regorafenib and at defined time points during administration of regorafenib for treatment efficacy in colorectal cancer patients in terms of overall survival (OS).