Liu, N. et al. Serine protease inhibitor 2A is a protective factor for memory T cell development. Nat. Immunol. 5, 919-926
Committees on Immunology and Developmental Biology, Department of Pathology, Ben May Institute for Cancer Research and Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago, 924 East 57th Street, Chicago, Illinois 60637, USA. Nature Immunology
(Impact Factor: 20).
10/2004; 5(9):919-26. DOI: 10.1038/ni1107
An essential event in the development of memory CD8(+) T lymphocytes is the escape of progenitors from programmed cell death, but how this is mediated is unclear. Here we report that the gene encoding serine protease inhibitor 2A (Spi2A), an inhibitor of lysosomal executioner proteases dependent on transcription factor NF-kappaB, is upregulated in memory cell precursors. Spi2A upregulation protected lymphocytic choriomeningitis virus-specific memory progenitors from programmed cell death. Thus, Spi2A promotes the survival of cytotoxic T lymphocytes, allowing them to differentiate into memory CD8 T cells. These findings suggest a model in which commitment to the memory lineage is facilitated by the upregulation of protective genes.
Available from: Lingyang Xu
- "This determination was based on the downregulation of genes such as granzyme and perforin, which are the key cytotoxic proteins used by CTLs to kill their targets (Curtsinger et al. 2003; Mescher et al. 2006). A serine protease inhibitor Spi2a (Serpina3g), which has been implicated in aiding memory CTL formation (Liu et al. 2004), was upregulated. This means that rapamycin may also regulate memory-related genes like Spi2a directly. "
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ABSTRACT: Memory programming of cytotoxic T cells (CTLs) by inflammatory cytokines can be regulated by mammalian target of rapamycin (mTOR). We have shown that inhibition of mTOR during CTL activation leads to the enhancement of memory, but the molecular mechanisms remain largely unknown. Using high-throughput RNA-Seq, we identified genes and functions in mouse CTLs affected by mTOR inhibition through rapamycin. Of the 43,221 identified transcripts, 184 transcripts were differentially expressed after rapamycin treatment, corresponding to 128 annotated genes. Of these genes, 114 were downregulated and only 14 were upregulated. Most importantly, 50 of them are directly related to cell death and survival. In addition, several genes such as CD62L are related to migration. Furthermore, we predicted downregulation of transcriptional regulators based on the total differentially expressed genes, as well as the subset of apoptosis-related genes. Quantitative PCR confirmed the differential expressions detected in RNA-Seq. We conclude that the regulatory function of rapamycin may work through inhibition of multiple genes related to apoptosis and migration, which enhance CTL survival into memory.
Available from: Noam Alkan
- "Homology searches with AtSerpin1 sequence showed it to be most similar to vertebrate intracellular Clade B serpins (Fluhr et al., 2011) that monitor intracellular protease activity released from lysosomes (Silverman et al., 2004). For example, the serpin Spi2A (serine protease inhibitor 2A) promotes the survival of cytotoxic T lymphocytes by inhibiting executioner proteases released from the lysosome , thus allowing progenitors cells to differentiate into memory CD8 T-cells (Liu et al., 2004). In nematodes, the cytoplasmic localized serpin SRP-6 can inhibit calpains and lysosomal cysteine peptidases (cathepsins K, L, S and V). "
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ABSTRACT: Programmed cell death (PCD) in plants plays a key role in defense response and is promoted by the release of compartmentalized proteases to the cytoplasm. Yet the exact identity and control of these proteases is poorly understood. Serpins are an important group of proteins that uniquely curb the activity of proteases by irreversible inhibition; however, their role in plants remains obscure. Here we show that during cell death the Arabidopsis serpin protease inhibitor, AtSerpin1, exhibits pro-survival function by inhibiting its target pro-death protease, RD21. AtSerpin1 accumulates in the cytoplasm and RD21 accumulates in the vacuole and in ER-bodies. Elicitors of cell death, including the salicylic acid agonist, benzothiadiazole (BTH), and the fungal toxin, oxalic acid (OA), stimulated changes in vacuole permeability as measured by the changes in the distribution of marker dye. Concomitantly, covalent AtSerpin1-RD21 complex was detected indicative of a change in protease compartmentalization. Furthermore, mutant plants lacking RD21 or plants with AtSerpin1 over-expression exhibited significantly less elicitor-stimulated PCD than plants lacking AtSerpin1. Necrotrophic fungi Botrytis cinerea and Sclerotina sclerotiorum secrete oxalic acid as a toxin that stimulates cell death. Consistent with a pro-death function for RD21 protease, the growth of these necrotrophs was compromised in plants lacking RD21 but accelerated in plants lacking AtSerpin1. The results indicate that AtSerpin1controls the pro-death function of compartmentalized protease RD21 by determining a set-point for its activity and limiting the damage induced during cell death © 2013 The Authors. The Plant Journal © 2013 Blackwell Publishing Ltd.
Available from: Susan M Kaech
- "KLRG1 hi IL-7R lo TE cells depend on IL-15 and there was also no defect in IL-2/15 receptor β chain expression in Stat3 −/− memory cells. Lastly, gene expression profiling revealed that Stat3 −/− CD8 + T cells expressed higher than normal amounts of Spi2A, another prosurvival factor for memory CD8 + T cells (Liu et al., 2004). Thus, it is possible that these factors combined account for the persistence of Stat3 −/− memory CD8 + T cells. "
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ABSTRACT: Memory CD8(+) T cells are critical for long-term immunity, but the genetic pathways governing their formation remain poorly defined. This study shows that the IL-10-IL-21-STAT3 pathway is critical for memory CD8(+) T cell development after acute LCMV infection. In the absence of either interleukin-10 (IL-10) and IL-21 or STAT3, virus-specific CD8(+) T cells retain terminal effector (TE) differentiation states and fail to mature into protective memory T cells that contain self-renewing central memory T cells. Expression of Eomes, BCL-6, Blimp-1, and SOCS3 was considerably reduced in STAT3-deficient memory CD8(+) T cells, and BCL-6- or SOCS3-deficient CD8(+) T cells also had perturbed memory cell development. Reduced SOCS3 expression rendered STAT3-deficient CD8(+) T cells hyperresponsive to IL-12, suggesting that the STAT3-SOCS3 pathway helps to insulate memory precursor cells from inflammatory cytokines that drive TE differentiation. Thus, memory CD8(+) T cell precursor maturation is an active process dependent on IL-10-IL-21-STAT3 signaling.
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