Biology subjects

Su, D.-M.

Publications and source records attributed to Su, D.-M..

2 recordsLinked to original sources

bioRxiv2021

Accumulation of Treg cells is detrimental in late-onset (aged) mouse model of multiple sclerosis

Although typically associated with onset in young adults, multiple sclerosis (MS) also attacks aged people, which is termed late-onset MS. The disease can be recapitulated and studied in the aged mouse model of experimental autoimmune encephalomyelitis (EAE). The onset of induced EAE is delayed in aged mice, but the disease severity is increased relative to standard EAE in young mice. Given that CD4+FoxP3+ regulatory T (Treg) cells play an ameliorative role in MS/EAE severity and the aged immune system accumulates Treg cells, failure of these cells to prevent or ameliorate EAE disease is enigmatic. When analyzing the distribution of Treg cells in EAE mice, the aged mice exhibited a higher proportion of polyclonal(pan) Treg cells and a lower proportion of antigen-specific-Treg cells in their periphery, but lower proportions of pan- and antigen-specific-Treg cells in the central nervous system (CNS). Furthermore, in the aged CNS, Treg cells exhibited a higher plasticity and T effector (Teff) cells exhibited a greater clonal expansion, which disrupted the Treg/Teff balance. Transiently inhibiting FoxP3 expression in peripheral Treg cells partially ameliorated the disease and corrected Treg distribution in the aged mice. These results provide evidence that accumulated aged Treg cells play a detrimental role in neuronal inflammation of aged MS. HighlightsO_ST_ABSQuestionC_ST_ABSCD4+ regulatory T (Treg) cells typically play an ameliorative role in multiple sclerosis (MS) onset and severity. However, why aged immune system has accumulated peripheral Treg cells, but the elderly has more severe MS symptoms? FindingsAged Treg cells cannot easily distribute to the CNS of aged EAE mice, and those aged Treg cells that did enter the CNS exhibited increased plastic features. However, transient inhibition of peripherally accumulated Treg cells corrected Treg distribution and partially ameliorated the disease in the aged mice. Conclusion and mechanistic insightsAccumulated aged Treg cells within an "inflammaging" condition do not play an ameliorative role but are potentially detrimental for inflamed CNS repair processes in aged EAE mice due to impeding the trafficking of immune cells into the inflamed CNS. O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

immunology↗

bioRxiv2020

Thymic rejuvenation via induced thymic epithelial cells (iTECs) from FOXN1-overexpressing fibroblasts to counteract inflammaging

Age-associated systemic, chronic, sterile inflammatory condition (inflammaging) is partially attributed to increased self (auto)-reactivity, resulting from disruption of central tolerance in the aged, involuted thymus. Age-related thymic involution causally results from gradually declined expression of the transcription factor forkhead box N1 (FOXN1) in thymic epithelial cells (TECs), while exogenous FOXN1 in TECs can significantly rescue age-related thymic involution. Given the findings that induced TECs (iTECs) from FOXN1-overexpressing embryonic fibroblasts can generate an ectopic de novo thymus under the kidney capsule and intra-thymically injected natural young TECs can lead to middle-aged thymus regrowth, we sought to expand upon these two findings by applying them as a novel thymic rejuvenation strategy with two types of promoter-driven (Rosa26CreERT and FoxN1Cre) Cre-mediated iTECs. We engrafted iTECs, rather than natural young TECs, directly into the aged thymus and/or peri-thymus and found a significantly rejuvenated architecture and function in the native aged murine thymus. The engrafted iTECs drove regrowth of the aged thymus in both male and female mice, showing not only increased thymopoiesis, but also reinforcement of thymocyte negative selection, thereby, reducing senescent T cells and auto-reactive T cell-mediated inflammaging phenotypes in old mice. Therefore, this is a promising thymic rejuvenation strategy with preclinical significance, which can potentially rescue declined thymopoiesis and impaired negative selection to significantly, albeit partially, restore the defective central tolerance and reduce subclinical chronic inflammatory symptoms in the elderly. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=165 HEIGHT=200 SRC="FIGDIR/small/995357v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@d48c22org.highwire.dtl.DTLVardef@3c3ac4org.highwire.dtl.DTLVardef@3636b3org.highwire.dtl.DTLVardef@1416073_HPS_FORMAT_FIGEXP M_FIG C_FIG A novel rejuvenation strategy via the FOXN1-TEC axis using induced two types of FOXN1-overexpressing embryonic fibroblasts (termed iTECs) by intrathymic injection is able to counteract age-related thymic involution, which rescued negative selection, thereby, reducing peripheral T cell-associated inflammaging conditions.

immunology↗