Hair follicle-derived IL-7 and IL-15 mediate skin-resident memory T cell homeostasis and lymphoma

The skin harbors a variety of resident leukocyte subsets that must be tightly regulated to maintain immune homeostasis. Hair follicles are unique structures in the skin that contribute to skin dendritic cell homeostasis via chemokine production. We demonstrate that CD4⁺ and CD8⁺ skin resident memory T cells (T_RM), responsible for long-term skin immunity, resided predominantly within the hair follicle epithelium of unperturbed epidermis. T_RM tropism for the epidermis and follicles was herein termed epidermotropism. Hair follicle-derived IL-15 was required for CD8⁺ T_RM, and IL-7 for CD8⁺ and CD4⁺ T_RM, to exert epidermotropism. The lack of either cytokine impaired hapten-induced contact hypersensitivity responses. In a model of cutaneous T cell lymphoma, epidermotropic CD4⁺ T_RM lymphoma cell localization depended on hair follicle-derived IL-7. These findings implicate hair follicle-derived cytokines as regulators of malignant and non-malignant T_RM cell tissue residence and suggest they may be targeted therapeutically in inflammatory skin disease and lymphoma.

An Enhancer of the IL-7 Receptor α-Chain Locus Controls IL-7 Receptor Expression and Maintenance of Peripheral T Cells

The IL-7R plays critical roles in lymphocyte development and homeostasis. Although IL-7R expression is strictly regulated during lymphocyte differentiation and the immune response, little is known regarding its in vivo regulation. To address this issue, we established a mouse line with targeted deletion of the conserved non-coding sequence 1 (CNS1) element found 3.6 kb upstream of the IL-7Rα promoter. We report that IL-7Rα is expressed normally on T and B cells in thymus and bone marrow of CNS1(-/-) mice except for in regulatory T cells. In contrast, these mice show reduced IL-7Rα expression in conventional CD4 and CD8 T cells as well as regulatory T, NKT, and γδ T cells in the periphery. CD4 T cells of CNS1(-/-) mice showed IL-7Rα upregulation in the absence of growth factors and IL-7Rα downregulation by IL-7 or TCR stimulation, although the expression levels were lower than those in control mice. Naive CD4 and CD8 T cells of CNS1(-/-) mice show attenuated survival by culture with IL-7 and reduced homeostatic proliferation after transfer into lymphopenic hosts. CNS1(-/-) mice exhibit impaired maintenance of Ag-stimulated T cells. Furthermore, IL-7Rα upregulation by glucocorticoids and TNF-α was abrogated in CNS1(-/-) mice. This work demonstrates that the CNS1 element controls IL-7Rα expression and maintenance of peripheral T cells, suggesting differential regulation of IL-7Rα expression between central and peripheral lymphoid organs.

STAT5 Orchestrates Local Epigenetic Changes for Chromatin Accessibility and Rearrangements by Direct Binding to the TCRγ Locus

The transcription factor STAT5, which is activated by IL-7R, controls chromatin accessibility and rearrangements of the TCRγ locus. Although STAT-binding motifs are conserved in Jγ promoters and Eγ enhancers, little is known about their precise roles in rearrangements of the TCRγ locus in vivo. To address this question, we established two lines of Jγ1 promoter mutant mice: one harboring a deletion in the Jγ1 promoter, including three STAT motifs (Jγ1P(Δ/Δ)), and the other carrying point mutations in the three STAT motifs in that promoter (Jγ1P(mS/mS)). Both Jγ1P(Δ/Δ) and Jγ1P(mS/mS) mice showed impaired recruitment of STAT5 and chromatin remodeling factor BRG1 at the Jγ1 gene segment. This resulted in severe and specific reduction in germline transcription, histone H3 acetylation, and histone H4 lysine 4 methylation of the Jγ1 gene segment in adult thymus. Rearrangement and DNA cleavage of the segment were severely diminished, and Jγ1 promoter mutant mice showed profoundly decreased numbers of γδ T cells of γ1 cluster origin. Finally, compared with controls, both mutant mice showed a severe reduction in rearrangements of the Jγ1 gene segment, perturbed development of γδ T cells of γ1 cluster origin in fetal thymus, and fewer Vγ3(+) dendritic epidermal T cells. Furthermore, interaction with the Jγ1 promoter and Eγ1, a TCRγ enhancer, was dependent on STAT motifs in the Jγ1 promoter. Overall, this study strongly suggests that direct binding of STAT5 to STAT motifs in the Jγ promoter is essential for local chromatin accessibility and Jγ/Eγ chromatin interaction, triggering rearrangements of the TCRγ locus.

Memory CD8(+) T cells colocalize with IL-7(+) stromal cells in bone marrow and rest in terms of proliferation and transcription

It is believed that memory CD8⁺ T cells are maintained in secondary lymphoid tissues, peripheral tissues, and BM by homeostatic proliferation. Their survival has been shown to be dependent on IL-7, but it is unclear where they acquire it. Here we show that in murine BM, memory CD8⁺ T cells individually colocalize with IL-7⁺ reticular stromal cells. The T cells are resting in terms of global transcription and do not express markers of activation, for example, 4-1BB (CD137), IL-2, or IFN-γ, despite the expression of CD69 on about 30% of the cells. Ninety-five percent of the memory CD8⁺ T cells in BM are in G₀ phase of cell cycle and do not express Ki-67. Less than 1% is in S/M/G₂ of cell cycle, according to propidium iodide staining. While previous publications have estimated the extent of proliferation of CD8⁺ memory T cells on the basis of BrdU incorporation, we show here that BrdU itself induces proliferation of CD8⁺ memory T cells. Taken together, the present results suggest that CD8⁺ memory T cells are maintained as resting cells in the BM in dedicated niches with their survival conditional on IL-7 receptor signaling.

B-cell progenitors and precursors change their microenvironment in fetal liver during early development

The microenvironments, in which B lymphocytes develop in fetal liver, are largely still unknown. Among the nonhematopoietic cells, we have identified and FACS-separated two subpopulations, CD45(-) TER119(-) VCAM-1(+) cells that are either CD105(high) LYVE-1(high) or CD105(low) ALCAM(high) . Immunohistochemical analyses find three of four c-Kit(+) IL-7Rα(+) B220(low) CD19(-) SLC(-) B progenitors in contact with vascular endothelial-type LYVE-1(high) cells on embryonic day 13.5. One day later c-Kit(+) IL-7Rα(+) cells develop to CD19(- and +) , SLC-expressing, DHJH-rearranged pre/pro and pro/preB-I cells. Less than 10% are still in contact with LYVE-1(high) cells, but half of them are now in contact with mesenchymally derived ALCAM(high) liver cells. All of these ALCAM(high) cells, but not the LYVE-1(high) cells produce IL-7 and CXCL12, while both produce CXCL10. Progenitors and pro/preB-I cells are chemoattracted in vitro toward CXCL10 and 12, suggesting that lymphoid progenitors with Ig gene loci in germline configuration enter the developing fetal liver at E13.5 from vascular endothelium, attracted by CXCL10, and then migrate within a day to an ALCAM(high) liver cell microenvironment, differentiating to DHJH-rearranging, surrogate light chain-expressing pre/proB and pro/preB-I cells, attracted by CXCL10 and 12. Between E15.5 and E16.5 preB-I cells expand 10-fold in continued contact with ALCAM(high) cells and begin VH- to DHJH-rearrangements in further differentiated c-Kit(-) IL-7Rα(-) preBII cells. STEM Cells 2013;31:2800-2812.

A genome-wide analysis identifies a notch-RBP-Jκ-IL-7Rα axis that controls IL-17-producing γδ T cell homeostasis in mice

Notch signaling is an important regulator for the development and function of both αβ and γδ T cells, whereas roles of Notch signaling in T cell maintenance remain unclear. We reported previously that the Notch-Hes1 pathway was involved in the intrathymic development of naturally occurring IL-17-producing (IL-17(+)) γδ T cells. To gain insight into additional roles for the Notch axis in the homeostasis of γδ T cells, we performed a genome-wide analysis of Notch target genes and identified the novel promoter site of IL-7Rα driven by the Notch-RBP-Jκ pathway. Constitutive Notch signaling had the potential to induce IL-7Rα expression on γδ T cells in vivo, as well as in vitro, whereas conditional deletion of RBP-Jκ abrogated IL-7Rα expression, but not Hes1 expression, by γδ T cells and selectively reduced the pool size of IL-7Rα(high) IL-17(+) γδ T cells in the periphery. In the absence of IL-7Rα-mediated signaling, IL-17(+) γδ T cells were barely maintained in adult mice. Addition of exogenous IL-7 in vitro selectively expanded IL-17(+) γδ T cells. Thus, our results revealed a novel role for the Notch-RBP-Jκ-IL-7Rα axis that is independent of Hes1 for homeostasis of IL-17(+) γδ T cells.

Reprint of: Environments of B cell development

B lymphocyte development in the mouse begins with the generation of long-term reconstituting, pluripotent hematopoietic stem cells, over multipotent myeloid/lymphoid progenitors and common lymphoid progenitors to B-lineage committed pro/pre B and pre B cells, which first express pre B cell receptors and then immunoglobulins, B cell receptors, to generate the repertoires of peripheral B cells. This development is influenced and guided by cells of non-hematopoietic and hematopoietic origins. We review here some of the recent developments, and our contributions in this fascinating field of developmental immunology.

Signal transducer and activator of transcription 3 (Stat3) contributes to T-cell homeostasis by regulating pro-survival Bcl-2 family genes

The naive T-cell pool in peripheral lymphoid tissues is fairly stable in terms of number, diversity and functional capabilities in spite of the absence of prominent stimuli. This stability is attributed to continuous tuning of the composition of the T-cell pool by various homeostatic signals. Despite extensive research into the link between signal transducer and activator of transcription 3 (Stat3) and T-cell survival, little is known about how Stat3 regulates homeostasis by maintaining the required naive T-cell population in peripheral lymphoid organs. We assessed whether the elimination of Stat3 in T cells limits T-cell survival. We demonstrated that the proportion and number of single-positive thymocytes as well as T cells in the spleen and lymph nodes were significantly decreased in the Stat3-deficient group as a result of the enhanced susceptibility of Stat3-deleted T lymphocytes to apoptosis. Importantly, expression of the anti-apoptotic Bcl-2 and Bcl-xL was markedly decreased in Stat3-deleted single-positive thymocytes and T lymphocytes, suggesting that Stat3 helps to maintain the T-cell pool in the resting condition by promoting the expression of Bcl-2 family genes. These findings suggest the importance of Stat3 in the integration of homeostatic cues for the maintenance and functional tuning of the T-cell pool.

microRNA-18a induces apoptosis in colon cancer cells via the autophagolysosomal degradation of oncogenic heterogeneous nuclear ribonucleoprotein A1

It is well known that microRNAs (miRs) are abnormally expressed in various cancers and target the messenger RNAs (mRNAs) of cancer-associated genes. While (miRs) are abnormally expressed in various cancers, whether miRs directly target oncogenic proteins is unknown. The present study investigated the inhibitory effects of miR-18a on colon cancer progression, which was considered to be mediated through its direct binding and degradation of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1). An MTT assay and xenograft model demonstrated that the transfection of miR-18a induced apoptosis in SW620 cells. A binding assay revealed direct binding between miR-18a and hnRNP A1 in the cytoplasm of SW620 cells, which inhibited the oncogenic functions of hnRNP A1. A competitor RNA, which included the complementary sequence of the region of the miR-18a-hnRNP A1 binding site, repressed the effects of miR-18a on the induction of cancer cell apoptosis. In vitro single and in vivo double isotope assays demonstrated that miR-18a induced the degradation of hnRNP A1. An immunocytochemical study of hnRNP A1 and LC3-II and the inhibition of autophagy by 3-methyladenine and ATG7, p62 and BAG3 siRNA showed that miR-18a and hnRNP A1 formed a complex that was degraded through the autophagolysosomal pathway. This is the first report showing a novel function of a miR in the autophagolysosomal degradation of an oncogenic protein resulting from the creation of a complex consisting of the miR and a RNA-binding protein, which suppressed cancer progression.

IL-7 produced by thymic epithelial cells plays a major role in the development of thymocytes and TCRγδ+ intraepithelial lymphocytes

IL-7 is a cytokine essential for T cell development and survival. However, the local function of IL-7 produced by thymic epithelial cells (TECs) is poorly understood. To address this question, we generated IL-7-floxed mice and crossed them with FoxN1 promoter-driven Cre (FoxN1-Cre) mice to establish knockout mice conditionally deficient for the expression of IL-7 by TECs. We found that αβ and γδ T cells were significantly reduced in the thymus of IL-7(f/f) FoxN1-Cre mice. Proportion of mature single-positive thymocytes was increased. In lymph nodes and the spleen, the numbers of T cells were partially restored in IL-7(f/f) FoxN1-Cre mice. In addition, γδ T cells were absent from the fetal thymus and epidermis of IL-7(f/f) FoxN1-Cre mice. Furthermore, TCRγδ(+) intraepithelial lymphocytes (IELs) were significantly decreased in the small intestines of IL-7(f/f) FoxN1-Cre mice. To evaluate the function of IL-7 produced in the intestine, we crossed the IL-7(f/f) mice with villin promoter-driven Cre (Vil-Cre) mice to obtain the mice deficient in IL-7 production from intestinal epithelial cells. We observed that αβ and γδ IELs of IL-7(f/f) Vil-Cre mice were comparable to control mice. Collectively, our results suggest that TEC-derived IL-7 plays a major role in proliferation, survival, and maturation of thymocytes and is indispensable for γδ T cell development. This study also demonstrates that IL-7 produced in the thymus is essential for the development of γδ IELs and indicates the thymic origin of γδ IELs.

Low-intensity resistance training after high-intensity resistance training can prevent the increase of central arterial stiffness

Although high-intensity resistance training increases arterial stiffness, low-intensity resistance training reduces arterial stiffness. The present study investigates the effect of low-intensity resistance training before and after high-intensity resistance training on arterial stiffness. 30 young healthy subjects were randomly assigned to a group that performed low-intensity resistance training before high-intensity resistance training (BLRT, n=10), a group that performed low-intensity resistance training after high-intensity resistance training (ALRT, n=10) and a sedentary control group (n=10). The BLRT and ALRT groups performed resistance training at 80% and 50% of one repetition maximum twice each week for 10 wk. Arterial stiffness was measured using carotid-femoral and femoral-ankle pulse wave velocity (PWV). One-repetition maximum strength in the both ALRT and BLRT significantly increased after the intervention (P<0.05 to P<0.01). Both carotid-femoral PWV and femoral-ankle PWV after combined training in the ALRT group did not change from before training. In contrast, carotid-femoral PWV after combined training in the BLRT group increased from before training (P <0.05). Femoral-ankle PWV after combined training in the both BLRT and ALRT groups did not change from before training. These results suggest that although arterial stiffness is increased by low-intensity resistance training before high-intensity resistance training, performing low-intensity resistance training thereafter can prevent the increase of arterial stiffness.

Role of hepatocyte-derived IL-7 in maintenance of intrahepatic NKT cells and T cells and development of B cells in fetal liver

The liver contains a variety of resident immune cells, such as NK cells, NKT cells, T cells, macrophages, and dendritic cells. However, little is known about how IL-7, which is produced by hepatocytes, functions locally in development and maintenance of liver immune cells. To address this question, we established IL-7-floxed mice and crossed them with albumin promoter-driven Cre (Alb-Cre) transgenic mice to establish conditional knockout of IL-7 in hepatocytes. The levels of IL-7 transcripts were reduced 10-fold in hepatocyte fraction. We found that the absolute numbers of NKT and T cells were significantly decreased in adult liver of IL-7(f/f) Alb-Cre mice compared with IL-7(f/f) control mice. In contrast, NK cells, dendritic cells, and B cells were unchanged in the IL-7(f/f) Alb-Cre liver. The number of Vα14(+) invariant NKT cells was significantly reduced in liver, but not in thymus and spleen, of IL-7(f/f) Alb-Cre mice. Furthermore, B cell development was impaired in perinatal liver of IL-7(f/f) Alb-Cre mice. This study demonstrates that hepatocyte-derived IL-7 plays an indispensable role in maintenance of NKT and T cells in adult liver and development of B cells in fetal liver, and suggests that hepatocytes provide a unique IL-7 niche for intrahepatic lymphocytes.

Identification of IL-7-producing cells in primary and secondary lymphoid organs using IL-7-GFP knock-in mice

IL-7 is a cytokine crucial for development and maintenance of lymphocytes and other hematopoietic cells. However, how IL-7-expressing cells are distributed in lymphoid organs is not well known. To address this question, we established and analyzed IL-7-GFP knock-in mice. Thymic epithelial cells (TECs) expressed high GFP levels in the cortex and medulla, as detected with an anti-GFP Ab. Thymic mesenchymal cells also expressed GFP. Flow cytometry analysis suggested that cortical TECs expressed higher GFP levels than did medullary TECs. In bone marrow, immunohistochemistry indicated high levels of GFP in many VCAM-1(+) mesenchymal stromal cells and in some VCAM-1(-) cells. Additionally, half of the VCAM-1(+)CD31(-) stromal cells and some platelet-derived growth factor receptor α(+) stromal cells were GFP(+), as detected by flow cytometry. Moreover, we detected GFP expression in fibroblastic reticular cells in the T cell zone and cortical ridge of lymph nodes. Remarkably, lymphatic endothelial cells (LECs) expressed GFP at high levels within the lymph node medulla, skin epidermis, and intestinal tissues. Additionally, we detected abundant IL-7 transcripts in isolated LECs, suggesting that LECs produce IL-7, a heretofore unknown finding. Furthermore, GFP is expressed in a subpopulation of intestinal epithelial cells, and that expression was markedly upregulated in a dextran sulfate sodium-induced acute colitis model. Overall, IL-7-GFP knock-in mice serve as a unique and powerful tool to examine the identity and distribution of IL-7-expressing cells in vivo.

Decompression procedure using a microendoscopic technique for thoracic myelopathy caused by ossification of the ligamentum flavum

BACKGROUND

Microendoscopic discectomy (MED) is one of the minimally invasive endoscopic procedures for treating lumbar disc herniation. The aim of this case report is to describe a patient with thoracic ossification of the ligamentum flavum (OLF) that was completely removed using the microendoscopic technique.

CASE REPORT

We report on a 62-year-old male patient who presented with thoracic myelopathy caused by OLF at the Th11-12. A posterior decompression via spinous process splitting approach using the microendoscopic technique at the Th11-12 was performed. The bilateral ossified ligamentum flavum could be en bloc removed separately. A sufficient decompression of the spinal cord and the spinal canal with no evidence of damage on the paraspinal muscles was demonstrated on magnetic resonance images after surgery. The patient's neurological symptoms were alleviated at 24 months after surgery. There was no evidence of postoperative instability at the final follow-up.

CONCLUSION

The authors found that the microendoscopic technique could be applied to decompression surgery for thoracic OLF. The procedure could provide a sufficient decompression with minimum damage to the paraspinal muscles. However, the microendoscopic procedure should be indicated only for select thoracic OLF, such as OLF without fusion at the middle of the spinal canal and OLF without dural ossification, because of its technical difficulties.

Variability of parvovirus B19 genotype 2 in plasma products with different compositions in the inactivation sensitivity by liquid-heating

BACKGROUND AND OBJECTIVES

Our previous report showed that parvovirus B19 genotype 1 in different solutions derived from plasma preparations showed different heat-sensitivity patterns during liquid-heating. In this study, we similarly examined B19 genotype 2.

MATERIALS AND METHODS

Two plasma samples one containing B19 genotype 1 and the other genotype 2 DNA were used. Four process samples collected immediately before the heat treatment step in the manufacture of albumin, immunoglobulin, haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60°C for 10 h. A low pH immunoglobulin solution was also spiked with B19 and treated at room temperature for 14 days. Infectivity was then measured.

RESULTS

B19 genotype 2, similar to genotype 1, showed three patterns of inactivation: (i) a rapid inactivation in the albumin and immunoglobulin preparations, (ii) a slow inactivation in the haptoglobin preparation and (iii) only limited inactivation in the antithrombin preparation. Its sensitivity in the low pH immunoglobulin solutions also resembled that of genotype 1.

CONCLUSION

Both genotypes 1 and 2 of B19 varied in sensitivity to liquid-heating and low pH among different plasma preparations.

The pre-TCR signal induces transcriptional silencing of the TCRγ locus by reducing the recruitment of STAT5 and Runx to transcriptional enhancers

The mouse TCRγ locus is positively regulated by the transcription factors STAT5 and Runx. While the locus undergoes frequent rearrangements in T lymphocytes, TCRγ transcription is repressed in αβ T cells. This phenomenon, known as TCRγ silencing, depends on pre-TCR-induced thymocyte proliferation. The molecular basis for TCRγ silencing, however, is largely unknown. Here, we show that pre-TCR signaling reduces transcription and histone acetylation of the TCRγ locus irrespective of V-J rearrangements. We also demonstrate that Runx is recruited to Eγ and HsA enhancer elements of the TCRγ locus, primarily at the CD4(-)CD8(-) double-negative stage and that Runx binding to these elements decreases at later stages of thymocyte development. Importantly, anti-CD3 antibody treatment decreased IL-7R expression levels, STAT5 phosphorylation and recruitment of STAT5 and Runx to Eγ and HsA elements in RAG2-deficient thymocytes, suggesting that pre-TCR signaling triggers reduced binding of STAT5 and Runx to the enhancer elements. Furthermore, we observed that misexpression of STAT5 or Runx in the CD4(+)CD8(+) double-positive cell line DPK induces TCRγ gene transcription. Finally, we showed that TCRγ transcription is induced in αβ T cells from Runx3 transgenic mice, suggesting that Runx3 counteracts TCRγ silencing in αβ T cells in vivo. Our results suggest that pre-TCR signaling indirectly inactivates TCRγ enhancers by reducing recruitment of STAT5 and Runx and imply that this effect is an important step for TCRγ silencing in αβ T cells.

Contribution of IL-17-producing gamma delta T cells to the efficacy of anticancer chemotherapy

IL-17 production by γδ T cells is required for tumor cell infiltration by IFN-γ–producing CD8⁺ T cells and inhibition of tumor growth in response to anthracyclines.

By triggering immunogenic cell death, some anticancer compounds, including anthracyclines and oxaliplatin, elicit tumor-specific, interferon-γ–producing CD8⁺ αβ T lymphocytes (Tc1 CTLs) that are pivotal for an optimal therapeutic outcome. Here, we demonstrate that chemotherapy induces a rapid and prominent invasion of interleukin (IL)-17–producing γδ (Vγ4⁺ and Vγ6⁺) T lymphocytes (γδ T17 cells) that precedes the accumulation of Tc1 CTLs within the tumor bed. In T cell receptor δ^−/− or Vγ4/6^−/− mice, the therapeutic efficacy of chemotherapy was compromised, no IL-17 was produced by tumor-infiltrating T cells, and Tc1 CTLs failed to invade the tumor after treatment. Although γδ T17 cells could produce both IL-17A and IL-22, the absence of a functional IL-17A–IL-17R pathway significantly reduced tumor-specific T cell responses elicited by tumor cell death, and the efficacy of chemotherapy in four independent transplantable tumor models. Adoptive transfer of γδ T cells restored the efficacy of chemotherapy in IL-17A^−/− hosts. The anticancer effect of infused γδ T cells was lost when they lacked either IL-1R1 or IL-17A. Conventional helper CD4⁺ αβ T cells failed to produce IL-17 after chemotherapy. We conclude that γδ T17 cells play a decisive role in chemotherapy-induced anticancer immune responses.

STM Observation on the Initial growth of Amorphous and Microcrystalline Silicon Films

Direct nanoscale observation on the nucleation and growth of hydrogenated amorphous and microcrystalline silicon on graphite substrates was made using scanning tunneling microscopy, atomic force microscopy, and Raman scattering spectroscopy. Nucleation of hydrogenated silicon clusters is initiated through the nucleation sites created by reactive hydrogen species coming from the source gas plasma. The difference in spatial distribution of nucleated clusters at the initial stage of deposition between a-Si:H and μc-Si:H is ascribed to the difference in the number density of nucleation sites which results in difference in the diffusion length of a SiH3 radical at the initial stage of deposition on the graphite substrate. The RMS roughness of μc-Si:H films is larger than that of a-Si:H when the film thickness is larger than 10 Å, which is opposite to the behavior at the initial nucleation stage on the graphite substrate.

Upregulated IL-7 receptor α expression on colitogenic memory CD4+ T cells may participate in the development and persistence of chronic colitis

We have previously demonstrated that IL-7 is essential for the persistence of colitis as a survival factor of colitogenic IL-7Rα-expressing memory CD4(+) T cells. Because IL-7Rα is broadly expressed on various immune cells, it is possible that the persistence of colitogenic CD4(+) T cells is affected by other IL-7Rα-expressing non-T cells. To test this hypothesis, we conducted two adoptive transfer colitis experiments using IL-7Rα(-/-) CD4(+)CD25(-) donor cells and IL-7Rα(-/-) × RAG-2(-/-) recipient mice, respectively. First, IL-7Rα expression on colitic lamina propria (LP) CD4(+) T cells was significantly higher than on normal LP CD4(+) T cells, whereas expression on other colitic LP immune cells, (e.g., NK cells, macrophages, myeloid dendritic cells) was conversely lower than that of paired LP cells in normal mice, resulting in predominantly higher expression of IL-7Rα on colitogenic LP CD4(+) cells, which allows them to exclusively use IL-7. Furthermore, RAG-2(-/-) mice transferred with IL-7Rα(-/-) CD4(+)CD25(-) T cells did not develop colitis, although LP CD4(+) T cells from mice transferred with IL-7Rα(-/-) CD4(+)CD25(-) T cells were differentiated to CD4(+)CD44(high)CD62L(-) effector-memory T cells. Finally, IL-7Rα(-/-) × RAG-2(-/-) mice transferred with CD4(+)CD25(-) T cells developed colitis similar to RAG-2(-/-) mice transferred with CD4(+)CD25(-) T cells. These results suggest that IL-7Rα expression on colitogenic CD4(+) T cells, but not on other cells, is essential for the development of chronic colitis. Therefore, therapeutic approaches targeting the IL-7/IL-7R signaling pathway in colitogenic CD4(+) T cells may be feasible for the treatment of inflammatory bowel diseases.

Lack of antibodies against the antigen domain 2 epitope of cytomegalovirus (CMV) glycoprotein B is associated with CMV disease after renal transplantation in recipients having the same glycoprotein H serotypes as their donors

Cytomegalovirus (CMV) reinfection of seropositive individuals has been associated with adverse outcomes in organ transplantation and is a frequent cause of congenital infection. Previously we demonstrated that mismatching of CMV glycoprotein H (gH) serotypes was associated with CMV disease after renal transplantation. Because the antigen domain 2 (AD2) epitope of glycoprotein B (gB) is conserved among CMV isolates and is one of the known targets of neutralizing antibodies, in this study we investigated whether antibodies against the epitope contribute to protection from CMV reinfection in renal transplantation, irrespective of gH serological matching. For this purpose, the gB and gH serology and clinical outcomes were analyzed retrospectively for 77 transplant recipients in the donor positive/recipient positive setting, who were managed by preemptive strategy. We found that there was a good negative correlation between the numbers of antigenemia-positive cells and the levels of antibodies against gB AD2 in the CMV-gH antibody matched group, but not in the CMV-gH antibody mismatched group. None of the recipients with antibodies against both gB AD2 and strain-specific epitopes of gH have experienced CMV disease during 6 month after transplantation, while 28% of those who lacked either/both antibody response needed preemptive therapy. Because the outcome was statistically significant, antibodies against gB AD2 can be a useful indicator to predict emergence of CMV disease for preemptive therapy, in addition to antibodies against the mismatched gH types.

Accessibility control of TCR Vγ region by STAT5

The signal of the IL-7R and signal transducers and activators of transcription (STAT) 5 plays an essential role in gammadelta T-cell development by inducing V-J recombination in the TCRgamma locus. Previously, we have shown that STAT5 binds to the Jgamma promoters and controls chromatin accessibility by histone acetylation. However, little is known on control mechanism of Vgamma region by the IL-7R. To elucidate the regulation by STAT5, we first analyzed the chromatin status of Vgamma region in primary thymocytes. The levels of histone H3 acetylation are high at Vgamma5, HsA element and Vgamma2 in Rag2(-/-) thymocytes but low in IL-7R alpha-chain (IL-7Ralpha)-deficient early thymocytes, suggesting that IL-7R signaling controls the accessibility of the Vgamma region. In addition, high levels of histone H3 acetylation and germ line transcription were induced at Vgamma5 and HsA by cytokine and STAT5 in cytokine-dependent Ba/F3 and other hematopoietic cell lines. Importantly, the chromatin accessibility of Vgamma5 gene is increased by cytokine signal. Furthermore, STAT5 was not recruited to a non-canonical STAT-binding motif in the endogenous chromatin of the Vgamma5 promoter by cytokine stimulation, while STAT5 binds to a consensus motif in the HsA element. In accordance with this result, STAT5 does not directly activate the Vgamma5 promoter by reporter assay. These results suggested that while STAT5 directly binds to HsA element and induces its histone acetylation, STAT5 indirectly activates the Vgamma5 promoter. Thus, this study implies a potential role of STAT5 in accessibility control of Vgamma region, especially at Vgamma5 and HsA.

Essential role of IL-17A in the formation of a mycobacterial infection-induced granuloma in the lung

Granulomas play an essential role in the sequestration and killing of mycobacteria in the lung; however, the mechanisms of their development and maturation are still not clearly understood. IL-17A is involved in mature granuloma formation in the mycobacteria-infected lung. Therefore, IL-17A gene-knockout (KO) mice fail to develop mature granulomas in the Mycobacterium bovis bacille Calmette-Guérin (BCG)-infected lung. This study analyzed the mechanism of IL-17A-dependent mature granuloma formation in the mycobacteria-infected lung. The IL-17A KO mice showed a normal level of nascent granuloma formation on day 14 but failed to develop mature granulomas on day 28 after the BCG infection in the lung. The observation implies that IL-17A is required for the maturation of granuloma from the nascent to mature stage. TCR gammadelta T cells expressing TCR Vgamma4 or Vgamma6 were identified as the major IL-17A-producing cells that resided in the BCG-induced lung granuloma. The adoptive transfer of the IL-17A-producing TCR gammadelta T cells reconstituted granuloma formation in the IL-17A KO mice. The expression of ICAM-1 and LFA-1, which are adhesion molecules important in granuloma formation, decreased in the lung of the BCG-infected IL-17A KO mice, and their expression was induced on BCG-infected macrophages in coculture with IL-17A-producing TCR gammadelta T cells. Furthermore, IL-17A KO mice showed not only an impaired mature granuloma formation, but also an impaired protective response to virulent Mycobacterium tuberculosis. Therefore, IL-17A produced by TCR gammadelta T cells plays a critical role in the prevention of M. tuberculosis infection through the induction of mature granuloma formation.

Activation of the mouse TCRgamma enhancers by STAT5

The IL-7R controls local accessibility of joining (J) gamma gene segments in the mouse TCRgamma locus by recruiting signal transducers and activators of transcription (STAT) 5 and transcriptional coactivators to the Jgamma germ line promoters and inducing histone acetylation and germ line transcription. Because STAT consensus motifs are conserved not only in the Jgamma promoters but also in the TCRgamma 3' enhancer (Egamma) elements, it is possible that STAT5 interacts with and activates Egamma. To address this question, we first showed that the lysine 4 residue of histone H3 is substantially methylated at Egamma1 and Egamma4 elements in wild-type early thymocytes and that the levels of the methylation are reduced in IL-7R alpha chain-deficient mice. We also showed that STAT5 has potential to elevate histone acetylation of the Egamma elements in a cytokine-dependent cell line by cytokine stimulation. Next, we demonstrated that STAT5 is recruited to the STAT consensus motifs in the Egamma elements after cytokine stimulation and that transcription factors Runt-related (Runx) and c-Myb are constitutively recruited to Egamma. Furthermore, we showed that STAT5 augments basal Egamma activity controlled by Runx and c-Myb. These results suggest that STAT5 is recruited to the consensus motifs in the Egamma elements by cytokine stimulation and augments basal Egamma activity independent of Runx and c-Myb. Therefore, this study implies that the Egamma elements might be activated in two successive steps, first by Runx and c-Myb and next by STAT5.

Dual role for Id2 in chemical carcinogen-induced skin tumorigenesis

Inhibitor of DNA binding 2 (Id2) is a negative regulator of basic helix-loop-helix transcription factors and is involved in the control of cellular differentiation and proliferation. By using a two-step chemical carcinogenesis protocol, we evaluated the role of Id2 in skin tumor formation in mice. Twenty weeks after the initiation, the number of tumors formed in the Id2(-/-) mice was 3.5-fold higher than that in their wild-type littermates, whereas the diameter of tumors in the Id2(-/-) mice was about half of that of the tumors in the wild-type mice. In the Id2(-/-) mice, epidermal gammadelta T cells, which play a key role in immunosurveillance against skin tumor development, were barely detectable. Although histological analyses demonstrated no apparent difference in tumor cell type, tumor vessel formation or apoptosis, the proportion of proliferating cells was reduced in the tumors in the Id2(-/-) mice compared with those in the wild-type mice. In the wild-type mice, the expression of Id2 was enhanced in skin tumors compared with that in ear epidermal cells. Biochemical analysis demonstrated that cyclin D1 was reduced at the protein level in the tumors in the Id2(-/-) mice, whereas other factors such as cyclin E and p27 were not altered significantly. Our results reveal that Id2 plays a dual role in skin tumorigenesis by suppressing tumor development through the establishment of epidermal gammadelta T cell-mediated skin immunosurveillance and by promoting tumor cell proliferation via the control of the cyclin D1 protein level.

Effects of muscle contraction timing during resistance training on vascular function

Muscle contractions in normal resistance training are performed by eccentric (ECC, lowering phase) and concentric (CON, lifting phase) muscle contractions. However, the difference in effects of timing of muscle contraction during resistance training on arterial stiffness is unknown. This study investigated the effect of muscle contraction timing during resistance training on vascular function in healthy young adults. Thirty healthy men were randomly assigned to group of resistance training with quick lifting and slow lowering (ERT, n=10), group of resistance training with slow lifting and quick lowering (CRT, n=10) and sedentary groups (SED, n=10). The ERT and CRT groups underwent two supervised resistance-training sessions per week for 10 weeks. The ERT group performed the on set of 8-10 repetitions with 3 s ECC and 1 s CON muscle contractions. In contrast, the CRT group performed the on set of 8-10 repetitions with 1 s ECC and 3 s CON muscle contractions. Brachial-ankle pulse wave velocity (baPWV) after ERT did not change from baseline. In contrast, baPWV after CRT increased from baseline (from 1049+/-37 to 1153+/-30 cm s(-1), P<0.05). No significant changes in flow-mediated dilation were observed in the ERT and CRT groups. These values did not change in the SED group. These findings suggest that although both training does not deteriorate a vascular endothelial function, resistance training with quick lifting and slow lowering (that is, ERT) prevent the stiffening of arterial stiffness.

Cutting edge: Inhibition of NF-kappaB-mediated TSLP expression by retinoid X receptor

The epithelial-derived cytokine thymic stromal lymphopoietin (TSLP) has important roles in the initiation of allergic airway inflammation and the activation of dendritic cells. We have shown that the human TSLP gene is regulated in a NF-kappaB-dependent manner; however the factors that negatively regulate TSLP expression are not known. In this study we demonstrate that 9-cis-retinoic acid (9-cis-RA) is a negative regulator of TSLP expression in airway epithelial cells. This inhibition is manifested as a block in the IL-1beta-mediated recruitment of NF-kappaB to the human TSLP promoter. 9-cis-RA-mediated inhibition is not restricted to TSLP gene expression but rather reflects a general inhibition of NF-kappaB activation, as other NF-kappaB-regulated-genes were also inhibited in a similar manner by 9-cis-RA treatment. Taken as a whole, these data demonstrate that inhibition of IL-1beta-dependent genes by active retinoid X receptors involves antagonism of NF-kappaB signaling.

Extent of hepatitis E virus elimination is affected by stabilizers present in plasma products and pore size of nanofilters

BACKGROUND AND OBJECTIVE

To investigate the physico-chemical properties of hepatitis E virus (HEV) with regard to inactivation/removal, we have studied four isolates with respect to sensitivity to heat during liquid/dry-heating as well as removal by nanofiltration.

MATERIALS AND METHODS

Hepatitis E virus in an albumin solution or phosphate-buffered saline (PBS) was liquid-heated at 60 degrees C for a preset time. HEV in a freeze-dried fibrinogen containing stabilizers was also dry-heated at 60 or 80 degrees C for a preset time. In addition, to clarify the removal of HEV, the purified virus in PBS was filtered using several types of virus-removal filter (nanofilters) that have different pore sizes. HEV infectivity or genome equivalents before and after the treatments were assayed by a semiquantitative cell-based infectivity assay or quantitative polymerase chain reaction assay, respectively.

RESULTS

Hepatitis E virus isolates in albumin solutions were inactivated slowly at 60 degrees C for 5 h and the resultant log reduction factor (LRF) was from 1.0 to > or = 2.2, whereas the virus in PBS was inactivated quickly to below the detection limit and the LRF was > or = 2.4 to > or = 3.7. The virus in a freeze dried fibrinogen containing trisodium citrate dihydrate and l-arginine hydrochloride as stabilizers was inactivated slowly and the LRF was 2.0 and 3.0, respectively, of the 72 h at 60 degrees C, but inactivated to below the detection limit within 24 h at 80 degrees C with an LRF of > or = 4.0. The virus in PBS was also confirmed as to be approximately 35 nm in diameter by nanofiltration. These results are useful for evaluating viral safety against HEV contamination in blood products.

CONCLUSION

The sensitivity of HEV to heat was shown to vary greatly depending on the heating conditions. On the other hand, the HEV particles were completely removed using 20-nm nanofilters. However, each inactivation/removal step should be carefully evaluated with respect to the HEV inactivation/removal capacity, which may be influenced by processing conditions such as the stabilizers used for blood products.

Demonstration of a Marek's disease virus-specific antigen in tumour lesions of chickens with Marek's disease using monoclonal antibody against a virus phosphorylated protein

By use of monoclonal antibody against a Marek's disease virus (MDV) serotype 1-specific phosphorylated protein, MDV antigen-positive cells were demonstrated in tumour lesions of various visceral organs of chickens with Marek's disease. However, these tumour lesions did not appear to have the MDV glycoproteins gA and gB, which are considered to be late gene products of the virus genome gA and gB as well as the phosphorylated protein were detected in the feather follicle epithelium, which is a permissive site for MDV replication.

IL-17A produced by gammadelta T cells plays a critical role in innate immunity against listeria monocytogenes infection in the liver

IL-17A is originally identified as a proinflammatory cytokine that induces neutrophils. Although IL-17A production by CD4(+) Th17 T cells is well documented, it is not clear whether IL-17A is produced and participates in the innate immune response against infections. In the present report, we demonstrate that IL-17A is expressed in the liver of mice infected with Listeria monocytogenes from an early stage of infection. IL-17A is important in protective immunity at an early stage of listerial infection in the liver because IL-17A-deficient mice showed aggravation of the protective response. The major IL-17A-producing cells at the early stage were TCR gammadelta T cells expressing TCR Vgamma4 or Vgamma6. Interestingly, TCR gammadelta T cells expressing both IFN-gamma and IL-17A were hardly detected, indicating that the IL-17A-producing TCR gammadelta T cells are distinct from IFN-gamma-producing gammadelta T cells, similar to the distinction between Th17 and Th1 in CD4(+) T cells. All the results suggest that IL-17A is a newly discovered effector molecule produced by TCR gammadelta T cells, which is important in innate immunity in the liver.

MEK1/2 induces STAT5-mediated germline transcription of the TCRgamma locus in response to IL-7R signaling

The IL-7R plays an essential role in gammadelta T cell development by inducing V-J recombination of the TCRgamma locus through STAT5. Although tyrosine residues in the intracellular domain of the mouse IL-7R alpha-chain (IL-7Ralpha) have been implicated in STAT5 activation, it is still unknown whether they are essential for gammadelta T cell development. In this study, we showed that those IL-7Ralpha tyrosine residues are not essential for gammadelta T cell development, because phenylalanine replacement of four intracellular tyrosine residues (IL-7R-FFFF) partially rescued gammadelta T cell development of IL-7Ralpha-/- progenitors. To examine signaling pathways activated by IL-7R-FFFF, we introduced a chimeric receptor consisting of the human IL-4R alpha-chain and mouse IL-7R-FFFF (4R/7R-FFFF) into an IL-7-dependent pre-B cell line and found that 4R/7R-FFFF induced TCRgamma germline transcription and STAT5 activation. Treatment of cells with MEK1/2 inhibitors significantly decreased levels of TCRgamma germline transcription and STAT5 tyrosine phosphorylation mediated by 4R/7R-FFFF, suggesting that MEK1/2 plays an alternative role in STAT5 activation by IL-7R. MEK1/2 associated with STAT5 and induced STAT5 tyrosine phosphorylation and DNA binding activity. Furthermore, MEK1 directly phosphorylated a STAT5 tyrosine residue in vitro. Finally, active MEK1 partially rescued TCRgamma germline transcription by IL-7R in a pre-T cell line. These results demonstrate that MEK1/2 induces TCRgamma germline transcription by phosphorylating STAT5 through IL-7R-FFFF and suggest a potential role for MAPK in IL-7R tyrosine-independent activation of STAT5.

Physical and functional interactions between STAT5 and Runx transcription factors

The signal transducers and activators of transcription (STAT) and the Runt-related (Runx) are two of major transcription factor families that play essential roles in lymphocyte development. Although the interaction of Runx2 with STAT1 and STAT3 has been reported before, the interaction between STAT5 and Runx family proteins has not been characterized. In this study, we first showed that STAT5 physically interacts with Runx1, Runx2 and Runx3 by co-immunoprecipitation experiments. The Runt domain of Runx proteins and the DNA-binding domain and alpha-helix loop structure of STAT5 are responsible for the interaction. When expressed in CHO cells, STAT5 inhibits the nuclear localization of Runx proteins and retains them in the cytoplasm. In addition, we showed by reporter assay that the interaction between STAT5 and Runx proteins mutually inhibits their transcriptional activity. Furthermore, Runx proteins inhibit the DNA-binding activity of STAT5. Finally, we found that Runx proteins suppress the transcription of an endogenous STAT5 target gene, cytokine-inducible SH2 protein-1, in an interleukin-3-dependent pro-B cell line, Ba/F3. These results collectively suggested that STAT5 and Runx proteins physically and functionally interact to mutually inhibit their transcriptional activity. Thus, this study implies a potential role of the STAT5-Runx interaction in lymphocyte development.

Transcriptional activation of mouse TCR Jγ4 germline promoter by STAT5

The IL-7 receptor (IL-7R) controls the accessibility of mouse TCRgamma locus, by recruiting STAT5 and transcriptional coactivators to the Jgamma1 germline promoter and inducing histone acetylation at nearby chromatin. Although a STAT motif is present in Jgamma4 germline promoter, it is still unknown whether STAT5 regulates the transcription of the Jgamma4 promoter. Here, we showed that cytokine stimulation induced Jgamma4-Cgamma4 germline transcripts in a pre-T cell line, Scid.adh, and a hematopoietic cell line, Ba/F3. A STAT consensus motif was present in 5' region of Jgamma4 gene segment. We found that STAT5 bound to the STAT motif of the Jgamma4 germline promoter in vitro by EMSA. In addition, we detected by chromatin immunoprecipitation assay that STAT5 was recruited to the endogenous Jgamma4 chromatin in Ba/F3 cells after cytokine stimulation. Finally, using reporter assay, we showed that the Jgamma4 germline promoter was activated by STAT5 and that mutation in the STAT motif abrogated the activity. Furthermore, this transactivation was augmented by transcriptional coactivators, CBP and p300. Collectively, these results demonstrate that STAT5 binds to the STAT motif in the Jgamma4 promoter and induces germline transcription. Thus, this study indicates that the IL-7R/STAT5 signal controls the transcription and accessibility of different clusters in the TCRgamma locus.

Surgical Complications of Microendoscopic Procedures for Lumbar Spinal Stenosis

Microendoscopic discectomy (MED) is one of the minimally invasive endoscopic procedures for treating lumbar disc herniation. We have applied MED techniques to posterior decompression procedures for treating lumbar spinal stenosis (LSS). In the present study, we examined the surgical complications in 114 consecutive patients surgically treated with MED procedures for LSS. Intraoperative complications occurred in 9 patients. Six patients (5.3%) experienced a dural tear, and three (2.6%) had a fracture of an inferior facet. Early postoperative complications occurred in 13 patients. Twelve patients (10.5%) experienced transient neurological complications. The clinical outcomes at the mean 28-month follow-up were not affected by these surgical complications. Other major complications such as nerve injury and surgical site infection were not observed. Most of the complications occurred in the initial series of patients, and the incidence of complications decreased with an increase in the surgeon's experience and the application of several preventive measures against the complications. The surgeon should undergo training when MED techniques are applied in surgical treatment in order to recognize the specific complications associated with such procedures and apply preventive measures against these complications.

Induction of the IL-7 receptor alpha chain in mouse peripheral B cells by glucocorticoids

Expression of the IL-7R alpha chain (IL-7R alpha) is strictly regulated during development and maturation of lymphocytes. While T cells express the IL-7R alpha in the periphery, B cells do not. Glucocorticoids (GCs) have pleiotypic effects on development and function of lymphocytes. Although GCs induce the transcription of IL-7R alpha gene in T cells, their effect on B cells is largely unknown. Here, we show that GCs induce the transcription and expression of IL-7R alpha in mouse peripheral B cells. This effect does not require de novo protein synthesis, because a protein synthesis inhibitor, cycloheximide, does not block the transcription. IL-7R signal pathway is intact in peripheral B cells because Stat5, one of the signal molecules of the IL-7R alpha, is phosphorylated by IL-7 stimulation. We also observed that IL-7 simulation induces the transcription of Cis-1, one of the target genes of Stat5. Furthermore, GC-induced IL-7R alpha can transmit survival signal in B cells. Therefore, this study demonstrates that GCs induce the transcription and expression of functional IL-7R alpha in peripheral B cells, and implies a potential role of the IL-7R in survival of B cells.