Chronic low-grade inflammation is a hallmark of aging, aka "inflammaging", which is linked to a wide range of age-associated diseases. Immune dysfunction increases disease susceptibility, and increases morbidity and mortality of aging. Innate immune cells, including monocytes, macrophages and neutrophils, are the first responders of host defense and the key mediators of various metabolic and inflammatory insults. Currently, the understanding of innate immune programming in aging is largely fragmented. Here we investigated the phenotypic and functional properties of innate immune cells in various peripheral tissues of young and aged mice under normal and endotoxic conditions. Under the steady state, aged mice showed elevated pro-inflammatory monocytes/macrophages in peripheral blood, adipose tissue, liver, and colon. Under lipopolysaccharide (LPS)-induced inflammatory state, the innate immune cells of aged mice showed a different response to LPS stimulus than that of young mice. LPS-induced immune responses displayed differential profiles in different tissues and cell types. In the peripheral blood, when responding to LPS, the aged mice showed higher neutrophils, but lower pro-inflammatory monocytes than that in young mice. In the peritoneal fluid, while young mice exhibited significantly elevated pro-inflammatory neutrophils and macrophages in response to LPS, aged mice exhibited decreased pro-inflammatory neutrophils and variable cytokine responses in macrophages. In the adipose tissue, LPS induced less infiltrated neutrophils but more infiltrated macrophages in old mice than young mice. In the liver, aged mice showed a more robust increase of pro-inflammatory macrophages compared to that in young mice under LPS stimulation. In colon, macrophages showed relatively mild response to LPS in both young and old mice. We have further tested bone-marrow derived macrophages (BMDM) from young and aged mice, we found that BMDM from aged mice have impaired polarization, displaying higher expression of pro-inflammatory markers than those from young mice. These data collectively suggest that innate immunity in peripheral tissues is impaired in aging, and the dysregulation of immunity is tissue- and cell-dependent. Our findings in the rodent model underscore the complexity of aging immunity. Further investigation is needed to determine whether the immune profile observed in aged mice is applicable in age-associated diseases in humans.
Copyright © 2024 Noh, Han, Kim, Giles, Farnell, Wright and Sun.

In response to T-dependent Ag, germinal centers (GC) generate bone marrow-resident plasma cells (BMPC) and memory B cells (MBC). In this study, we demonstrate that the bone morphogenetic protein receptor 1A (BMPR1A) signaling pathway, which regulates differentiation and self-renewal in multiple stem cell populations, regulates GC dynamics and resultant establishment of BMPC and MBC. Expression studies using quantitative PCR and novel Bmpr1aIRES.EGFP reporter mice demonstrated that Bmpr1a expression is upregulated among GC B cells (GCBC) and subsets of MBC, bone marrow plasmablasts, and BMPC. In immunized mice carrying B cell-targeted Bmpr1a gene deletions, the GC response was initially diminished. Subsequently, the GCBC compartment recovered in size, concurrent with accumulation of GCBC that carried unmodified rather than deleted Bmpr1a alleles. Similarly, the resulting class-switched MBC and BMPC carried retained non-recombined alleles. Despite the strong selective pressure for "leaky" B cells that retained Bmpr1a, there was a permanent marked reduction in switched bone marrow Ab-forming cells (plasmablasts + plasma cells), BMPC, MBC, and Ag-specific serum IgM in mice carrying B cell-targeted Bmpr1a gene deletions. These findings demonstrate a novel role for BMPR1A in the modulation of the B cell response and in the establishment of long-term memory.
Copyright © 2021 The Authors.

Wogonin (5,7-dihydroxy-8-methoxyflavone) is an ingredient of the extracts from Scutellaria baicalensis, which has documented a wide spectrum of anti-inflammatory and antitumor activities, including inhibiting regulatory T cells, regulating effector T cell functions, and mediating macrophage immunity. However, the potential effect of Wogonin on B cells has not been fully understood. Here, our results showed that Wogonin inhibited IL-10 secretion in B cells. When purified B cells were activated by lipopolysaccharide (LPS) in vitro, the amount of IL-10 production in supernatant was decreased by Wogonin significantly. The protective role of B cells on dextran sulfate sodium- (DSS-) induced colitis was alleviated after exposure to Wogonin. Furthermore, administration of Wogonin on LPS-treated B cells suppressed phosphorylation of STAT3 and ERK, but not AKT. Interestingly, among those IL-10 signaling-associated transcription factors, mRNA and protein levels of Hif-1α were specifically decreased by Wogonin. Overall, our study indicates that Wogonin suppresses potentially IL-10 production in B cells via inhibition of the STAT3 and ERK signaling pathway as well as inhibition of mRNA and protein levels of the transcription factor Hif-1α. These results provide novel and potential molecular targets of Wogonin in B cells and help us further understand its mechanism of action, which could potentially improve its clinical application in the future.
Copyright © 2020 Li Fan et al.

High morbidity and mortality are common traits of malignant tumours and identification of the cells responsible is a focus of on-going research. Many studies are now reporting the use of antibodies specific to Clusters of Differentiation (CD) cell surface antigens to identify tumour-initiating cell (TIC) populations in neural tumours. Medulloblastoma is one of the most common malignant brain tumours in children and despite a considerable amount of research investigating this tumour, the identity of the TICs, and the means by which such cells can be targeted remain largely unknown. Current prognostication and stratification of medulloblastoma using clinical factors, histology and genetic profiling have classified this tumour into four main subgroups: WNT, Sonic hedgehog (SHH), Group 3 and Group 4. Of these subgroups, SHH remains one of the most studied tumour groups due to the ability to model medulloblastoma formation through targeted deletion of the Shh pathway inhibitor Patched1 (Ptch1). Here we sought to utilise CD antibody expression to identify and isolate TIC populations in Ptch1 deleted medulloblastoma, and determine if these antibodies can help classify the identity of human medulloblastoma subgroups. Using a fluorescence-activated cell sorted (FACS) CD antibody panel, we identified CD24 as a marker of TICs in Ptch1 deleted medulloblastoma. CD24 expression was not correlated with markers of astrocytes or oligodendrocytes, but co-labelled with markers of neural progenitor cells. In conjunction with CD15, proliferating CD24+/CD15+ granule cell precursors (GCPs) were identified as a TIC population in Ptch1 deleted medulloblastoma. On human medulloblastoma, CD24 was found to be highly expressed on Group 3, Group 4 and SHH subgroups compared with the WNT subgroup, which was predominantly positive for CD15, suggesting CD24 is an important marker of non-WNT medulloblastoma initiating cells and a potential therapeutic target in human medulloblastoma. This study reports the use of CD24 and CD15 to isolate a GCP-like TIC population in Ptch1 deleted medulloblastoma, and suggests CD24 expression as a marker to help stratify human WNT tumours from other medulloblastoma subgroups.

Immunological characterization of immune cells that reside in specific anatomic compartments often requires their isolation from the respective tissue on the basis of enzymatic tissue disintegration. Applying enzymatic digestion of primary splenocytes, we evaluated the impact of collagenase and dispase, two enzymes that are commonly used for the liberation of immune cells from tissues, on the detectability of 48 immunologically relevant surface molecules that are frequently used for flow cytometric identification, isolation, and characterization of immune cell subsets. Whereas collagenase treatment had only minor effects on surface expression of most molecules tested, dispase treatment considerably affected antibody-mediated detectability of the majority of surface markers in subsequent FACS analyses. This effect was long lasting and, in case of high-dose dispase treatment, evident for the majority of surface molecules even after 24 h of in vitro culture. Of note, high-dose dispase treatment not only affected surface expression of certain molecules but also impaired antigen-specific proliferation of CD4(+) and CD8(+) T cells. Together, our data indicate that enzymatic tissue disintegration can have profound effects on the expression of a variety of cell-surface molecules with direct consequences for phenotypic analysis, FACS- and MACS-based target cell isolation, and immune cell function in cell culture experiments.