S100A8, which increases with age, induces cellular senescence-like changes in bovine oviduct epithelial cells

Role of diesel exhaust particle-induced cellular senescence in the development of asthma in young and old mice

BACKGROUND

Although it has been reported that cellular senescence is important in the pathogenesis of asthma, the differential effects of diesel exhaust particle (DEP)-induced cellular senescence on the development of asthma according to age have not been thoroughly studied.

METHODS

We first confirmed that DEP induced cellular senescence in mouse lungs, and then that DEP-induced cellular senescence followed by intranasal instillation of a low-dose house dust mite (HDM) allergen resulted in murine asthma. Second, we examined age-dependent differential effects using 6-week-old (young) and 18-month-old mice (old), and tested whether the mammalian target of the rapamycin (mTOR) pathway plays an important role in this process. Finally, we performed in vitro experiments using human bronchial epithelial cells (HBEC) originating from young and elderly adults to identify the underlying mechanisms.

RESULTS

DEP induced cellular senescence in the airway epithelial cells of young and old mice characterized by increased senescence-associated beta-galactosidase, S100A8/9, and high mobility group box 1 (HMGB1) expressions. DEP-induced cellular senescence with subsequent exposure to a low-dose HDM allergen resulted in asthma in young and old mice. Rapamycin (mTOR pathway inhibitor) administration before DEP instillation significantly attenuated these asthmatic features. In addition, after treatment with a low-dose HDM allergen, S100A9 and HMGB1 over-expressed HBEC originating from young and elderly adults greatly activated co-cultured monocyte-derived dendritic cells (DCs).

CONCLUSIONS

This study showed that DEP-induced senescence made both young and old mice susceptible to allergic sensitization and resultant asthma development by enhancing DC activation. Public health efforts to reduce DEP exposure are warranted.

Decreased intranuclear cardiac troponin I impairs cardiac autophagy through FOS/ATG5 in ageing hearts

In our previous study, intranuclear cardiac troponin I (cTnI) may function as a co-factor of Yin Yang 1(YY1). Here, we aimed to explore the role of intranuclear cTnI in ageing hearts. Nuclear translocation of cTnI was demonstrated using Western blot and immunofluorescence. The potential nuclear localization sequences (NLSs) of cTnI were predicted by a web server and then verified in 293T cells by putative NLS-eGFP-GST and NLS-mutant transfection. The ratio of Nuclear cTnI/ Total cTnI (Nu/T) decreased significantly in ageing hearts, accompanied with ATG5-decline-related impaired cardiac autophagy. RNA sequencing was performed in cTnI knockout hearts. The differential expressed genes (DEGs) were analysed by overlapping with YY1 ChIP-sequencing data. cTnI gain and loss experiments in vitro determined those filtered DEGs' expression levels. A strong correlation was found between expression patterns cTnI and FOS. Using ChIP-q-PCR, we demonstrated that specific binding DNA sequences of cTnI were enriched in the FOS promoter -299 to -157 region. It was further verified that pcDNA3.1 (-)-cTnI could increase the promoter activity of FOS by using luciferase report assay. At last, we found that FOS can regulate the ATG5 (autophagy-related gene 5) gene by using a luciferase report assay. Taken together, our results indicate that decreased intranuclear cTnI in ageing hearts may cause impaired cardiac autophagy through the FOS/ATG5 pathway.

TLR9 Mediates Periodontal Aging by Fostering Senescence and Inflammaging

TLR9 is a critical nucleic acid sensing receptor in mediating periodontitis and periodontitis-associated comorbidities. Emerging evidence implicates TLR9 as a key sensor during aging, although its participation in periodontal aging is unexplored. Here, we investigated whether TLR9-mediated host responses can promote key hallmarks of aging, inflammaging, and senescence, in the course of periodontitis using a multipronged approach comprising clinical and preclinical studies. In a case-control model, we found increased TLR9 gene expression in gingival tissues of older (≥55 y) subjects with periodontitis compared to older healthy subjects as well as those who are younger (<55 y old) with and without the disease. Mechanistically, this finding was supported by an in vivo model in which wild-type (WT) and TLR9-/- mice were followed for 8 to 10 wk (young) and 18 to 22 mo (aged). In this longitudinal model, aged WT mice developed severe alveolar bone resorption when compared to their younger counterpart, whereas aged TLR9-/- animals presented insignificant bone loss when compared to the younger groups. In parallel, a boosted inflammaging milieu exhibiting higher expression of inflammatory/osteoclast mediators (Il-6, Rankl, Cxcl8) and danger signals (S100A8, S100A9) was noted in gingival tissues of aged WT mice compared to the those of aged TLR9-/- mice. Consistently, WT aged mice displayed an increase in prosenescence balance as measured by p16INK4a/p19ARF ratio compared to the younger groups and aged TLR9-/- animals. Ex vivo experiments with bone marrow-derived macrophages primed by TLR9 ligand (ODN 1668) further corroborated in vivo and clinical data and showed enhanced inflammatory-senescence circuit followed by increased osteoclast differentiation. Together, these findings reveal first systematic evidence implicating TLR9 as one of the drivers of periodontitis during aging and functioning by boosting a deleterious inflammaging/senescence environment. This finding calls for further investigations to determine whether targeting TLR9 will improve periodontal health in an aging population.

Mitochondrial Fus1/Tusc2 and cellular Ca2+ homeostasis: tumor suppressor, anti-inflammatory and anti-aging implications

FUS1/TUSC2 (FUSion1/TUmor Suppressor Candidate 2) is a tumor suppressor gene (TSG) originally described as a member of the TSG cluster from human 3p21.3 chromosomal region frequently deleted in lung cancer. Its role as a TSG in lung, breast, bone, and other cancers was demonstrated by several groups, but molecular mechanisms of its activities are starting to unveil lately. They suggest that Fus1-dependent mechanisms are relevant in etiologies of diseases beyond cancer, such as chronic inflammation, bacterial and viral infections, premature aging, and geriatric diseases. Here, we revisit the discovery of FUS1 gene in the context of tumor initiation and progression, and review 20 years of research into FUS1 functions and its molecular, structural, and biological aspects that have led to its use in clinical trials and gene therapy. We present a data-driven view on how interactions of Fus1 with the mitochondrial Ca2+ (mitoCa2+) transport machinery maintain cellular Ca2+ homeostasis and control cell apoptosis and senescence. This Fus1-mediated cellular homeostasis is at the crux of tumor suppressor, anti-inflammatory and anti-aging activities.

Age-related differential gene expression in granulosa cells and its effects on fertility using high-throughput transcriptomics

More couples worldwide, delay their childbearing years. The increase in age causes a gradual decrease in female ovarian function and fertility, leading to an exponential decrease in women over 35 years of age having children. Although promising for some, assisted reproductive technology (ART) is not promising for older women. Decreased fertility in advanced age has become a growing concern in the field of reproduction. In this study, high-throughput transcriptome sequencing was used to identify the differentially expressed genes (DEGs) in the ovarian granulosa cells (GCs) of older women (aged 35-44) with infertility and younger women (aged 25-34). The enriched functions and signaling pathways of DEGs were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The function of DEGs were analyzed and predicted combined with clinical ART data. Sequencing results were verified by quantitative reverse transcription-polymerase chain reaction. Retrospective clinical data and bioinformatics analyses revealed marked reductions in the retrieved oocyte, metaphase II oocyte, 2PN fertilization, and effective embryo numbers in older women. Although the clinical pregnancy and live birth rates did not differ notably between the groups, the miscarriage rate increased significantly in older women. In total, 620 DEGs were identified, of which 246 were upregulated, and 374 were downregulated in the older group. GO, and KEGG analyses indicated that the mechanism of fertility decline in older women was probably related to chronic inflammation, cytokine receptor interaction, and oxidative stress. In conclusion, combined with basic clinical ART data and pregnancy outcomes, we tried to provide a more intuitive and in-depth understanding of age-related reduction in ovarian function and pathogenesis of infertility with regard to chronic inflammation and oxidative stress.

S100A8 expression in oviduct mucosal epithelial cells is regulated by estrogen and affects mucosal immune homeostasis

Chronic inflammation can cause oviduct mucosal damage and immune dysfunction, leading to infertility, early pregnancy loss, ectopic pregnancy, tumors, and a decrease in reproductive capacities in female animals. Estrogen can suppress immune responses in different tissues and oviducts, and regulate the oviduct immune balance; however, the underlying mechanisms remain unclear. The objective of this study was to explore the mechanism of estrogen-regulated oviduct mucosal immunity and discover new estrogen targets for regulating oviduct mucosal immune homeostasis. Sheep oviduct epithelial cells (SOECs) were treated with 17-β estradiol (E2). Transcriptome sequencing and analysis showed differentially expressed S100 calcium-binding protein A (S100A) genes that may participate in the oviduct mucosa immunoregulation of estrogen. Quantitative polymerase chain reaction and immunocytochemistry analysis showed that S100A8 expression changed dynamically in E2-treated SOECs and peaked after 7 h of treatment. Estrogen nuclear receptors and G protein-coupled membrane receptors promoted E2-dependent S100A8 upregulation. The S100A8 gene was disrupted using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 method. Levels of inflammatory factors interleukin (IL)-1β and IL-4 were significantly upregulated in S100A8-knockdown SOECs, whereas those of the anti-inflammatory factor IL-10 was downregulated. Following S100A8 knockdown in SOECs treated with E2 for 7 h, IL-10 levels increased significantly. Estrogen affected oviduct mucosa immune function and dynamically regulated S100A8 in SOECs. S100A8 knockdown caused an excessive immune response, indicating that S100A8 is beneficial for maintaining immune homeostasis in the oviduct mucosa. Moreover, estrogen can compensate for the effect of S100A8 knockdown by upregulating IL-10.

Tumour inflammation signature and expression of S100A12 and HLA class I improve survival in HPV-negative hypopharyngeal cancer

Hypopharyngeal squamous cell carcinoma (HPSCC) has a very poor prognosis. Local surgery may increase survival, but is often avoided due to significant post-op co-morbidities. Since prognostic markers are lacking, the aim was to find predictive biomarkers that identify patients whose response to oncological treatment is poor and who may benefit from primary surgery to increase survival. Pretreatment biopsies from 23 HPSCC patients, 3 human papillomavirus (HPV) positive and 20 HPV-negative, were analyzed for expression of 750 mRNAs using the Nanostring nCounter IO360 panel in relation to 3-year survival. Validation was performed through immunohistochemistry (IHC) for HLA class I and S100A12 in 74 HPV-negative HPSCC samples. Clustering identified a subset of HPV-negative HPSCC with favorable prognosis and a gene expression signature overexpressing calgranulins and immune genes, distinct from that of HPV-positive HPSCC. Enrichment analysis showed immune signaling, including the tumor inflammation signature, to be enriched in surviving patients. IHC validation confirmed high S100A12 and HLA class I expression to correlate with survival in HPV-negative HPSCC. This shows that immune activity is strongly related to survival in HPV-negative HPSCC. Enrichment of the tumor inflammation signature indicates a potential benefit of immunotherapy. Low expression of both HLA class I and S100A12 could be used to select patients for local surgery.

IL1B triggers inflammatory cytokine production in bovine oviduct epithelial cells and induces neutrophil accumulation via CCL2

PROBLEM

The oviduct is essential for reproduction. We previously showed that oviduct epithelial cells (OECs) isolated from aged cows expressed higher levels of inflammatory cytokines, including interleukin (IL) 1A and IL1B. In addition, aging is associated with tissue dysfunction and cellular senescence via a senescence-associated secretory phenotype (SASP) and immune cell accumulation. We investigated whether IL1A or IL1B causes SASP production, cellular senescence, and inflammatory responses in bovine OECs.

METHOD OF STUDY

The OECs were isolated from bovine oviducts from young (mean 50.3 months) and aged cows (mean 157.0 months) and cultured.

RESULTS

Treatment with IL1A or IL1B induced SASP production (IL8, IL6, TNFA, and CCL2) and mRNA expression of cell adhesion molecules in bovine OECs, but both IL1s did not induce cellular senescence in OECs and migration of polymorphonuclear neutrophils (PMNs). Cultured medium of OECs treated with IL1s, especially IL1B, dramatically induced PMN migration. Treatment with the CCL2 inhibitor, but not IL8 or its receptor CXCR2 inhibitors, significantly reduced immune cell migration in IL1B-treated OEC-cultured medium. Treatment with IL1B increased PMN adhesion to OECs, resulting in further SASP production in OECs due to a PMN-OEC interaction.

CONCLUSION

We suggest that senescence-associated IL1s cause SASP production in bovine OECs and CCL2 induced by IL1B is essential for the migration of immune cells to OECs. Specifically, IL1B regulates PMN migration and adhesion to bovine OECs, and PMNs accelerate inflammatory cytokine production from bovine OECs via a direct interaction. These phenomena may contribute to chronic oviductal inflammation, resulting in subfertility.

Adverse reproductive effects of S100A9 on bovine sperm and early embryonic development in vitro

The phenomenon of aging arises from multiple, complex interactions causing dysfunction in cells and organs. In particular, fertility drastically decreases with age. Previously, we have demonstrated that the functional characteristics of the bovine oviduct and uterus change with the age-dependent upregulation of inflammation and noted that S100A9 triggers inflammatory responses in oviduct epithelial cells. In the present study, we investigated the hypothesis that S100A9 affects reproductive events to aspect such as sperm function, fertilization, and the development of the embryo in cows. To investigate the effect of S100A9 on bovine sperm, we incubated sperms in vitro with S100A9 for 5 h and observed significantly decreased sperm motility and viability. During in vitro fertilization, S100A9 treatment for 5 h did not affect the rate of fertilization, time of first division of embryos, or embryo development to blastocyst stage. Treatment of 2-cell stage embryos with S100A9 for 5 h significantly reduced the proportion of cells undergoing normal division (4-8 cell embryos) and embryo development to the blastocyst stage. In experiment involving 24 h treatment of 2-cell embryos, the development of all embryos stopped at the 2-cell stage in the S100A9-treated group. In blastocyst-stage embryos, S100A9 treatment significantly stimulated the expression of endoplasmic reticulum (ER) and the mRNA expression of ER stress markers, and activated caspase-3 with subsequent nuclear fragmentation. Pre-treatment with an ER stress inhibitor significantly suppressed caspase-3 activation by the S100A9 treatment, suggesting that S100A9 induces blastocyst dysfunction by apoptosis (via caspase-3 activation) depending on ER stress. These results indicate that direct exposure to S100A9 exerted adverse effects on sperm function and embryo development. These findings suggest that excessive dose of S100A9 may have an adverse effect to the reproductive machinery by inducing inflammation and tissue dysfunction.