Astrocytic neogenin/netrin-1 pathway promotes blood vessel homeostasis and function in mouse cortex

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Abstract

Astrocytes play multiple functions in the brain, including blood vessel (BV) homeostasis and function. However, the underlying mechanisms remain elusive. Here, we provide evidence for astrocytic neogenin (NEO1), a member of deleted in colorectal cancer (DCC) family netrin receptors, to be involved in this event. Mice with Neo1 depletion in astrocytes exhibited clustered astrocyte distribution and increased BVs in their cortex. These BVs were leaky with reduced blood flow, disrupted basement membranes (vBMs), decreased pericytes, impaired endothelial cell (EC) barrier, and elevated tip EC proliferation. Increased proliferation was also detected in cultured ECs exposed to the conditional medium (CM) of NEO1 depleted astrocytes. Further screening for angiogenetic factors in the CM identifies netrin-1 (NTN1), whose expression was decreased in NEO1 depleted cortical astrocytes. Adding NTN1 into the CM of NEO1 depleted astrocytes attenuated EC proliferation. Expressing NTN1 in NEO1 mutant cortical astrocytes ameliorated phenotypes in blood–brain barrier (BBB), EC, and astrocyte distribution. NTN1 depletion in astrocytes resulted in similar BV/BBB deficits in the cortex as those of Neo1 mutant mice. In aggregates, these results uncovered an unrecognized pathway, astrocytic NEO1 to NTN1, not only regulating astrocyte distribution, but also promoting cortical BV homeostasis and function.

Authors

Ling-ling Yao, Jin-xia Hu, Qiang Li, Daehoon Lee, Xiao Ren, Jun-shi Zhang, Dong Sun, Hong-sheng Zhang, Yong-gang Wang, Lin Mei, Wen-Cheng Xiong

Vaccine targeting SIVmac251 protease cleavage sites protects macaques against vaginal infection

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Abstract

After over three decades of research, an effective anti-HIV vaccine remains elusive. The recently halted HVTN702 clinical trial not only further stresses the challenge to develop an effective HIV vaccine, but also emphasizes that unconventional and novel vaccine strategies are urgently needed. Here, we report that a vaccine focusing the immune response on the sequences surrounding the 12 viral protease cleavage sites (PCSs) provided greater than 80% protection to Mauritian cynomolgus macaques (MCMs) against repeated intravaginal SIVmac251 challenges. The PCS-specific T cell responses correlated with vaccine efficacy. The PCS vaccine did not induce immune activation or inflammation known to be associated with increased susceptibility to HIV infection. Machine learning analyses revealed that the immune microenvironment generated by the PCS vaccine was predictive of vaccine efficacy. Our study demonstrates for the first time that a vaccine which targets only viral maturation, but lacks full-length Env and Gag immunogens, can prevent intravaginal infection in a stringent macaque/SIV challenge model. Targeting HIV maturation thus offers a novel approach to developing an effective HIV vaccine.

Authors

Hongzhao Li, Robert W. Omange, Binhua Liang, Nikki Toledo, Yan Hai, Lewis R. Liu, Dane Schalk, Jose Crecente-Campo, Tamara G. Dacoba, Andrew B. Lambe, So-Yon Lim, Lin Li, Mohammad Abul Kashem, Yanmin Wan, Jorge F. Correia-Pinto, Michael S. Seaman, Xiao-Qing Liu, Robert F. Balshaw, Qingsheng Li, Nancy Schultz-Darken, Maria Jose Alonso, Francis A. Plummer, James B. Whitney, Ma Luo

Tendon-derived cathepsin K-expressing progenitor cells activate Hedgehog signaling to drive heterotopic ossification

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Abstract

Heterotopic ossification (HO) is pathological bone formation characterized by ossification within muscle, tendons, or other soft tissues. However, the cells of origin and mechanisms involved in the pathogenesis of HO remain elusive. Here we show that deletion of Suppressor of fused (Sufu) in Cathepsin K-Cre-expressing (Ctsk-Cre-expressing) cells resulted in spontaneous and progressive ligament, tendon, and periarticular ossification. Lineage tracing studies and cell functional analysis demonstrated that Ctsk-Cre could label a subpopulation of tendon-derived progenitor cells (TDPCs) marked by tendon marker Scleraxis (Scx). Ctsk+Scx+ TDPCs are enriched for tendon stem cell markers and show the highest self-renewal capacity and differentiation potential. Sufu deficiency caused enhanced chondrogenic and osteogenic differentiation of Ctsk-Cre-expressing tendon-derived cells via upregulating Hedgehog (Hh) signaling. Furthermore, pharmacological intervention of hedgehog signaling using JQ1 suppressed the development of HO. Thus, our results display that Cathepsin K-Cre labels a subpopulation of TDPCs contributing to HO and their cell fate changes are driven by activation of Hh signaling.

Authors

Heng Feng, Wenhui Xing, Yujiao Han, Jun Sun, Mingxiang Kong, Bo Gao, Yang Yang, Zi Yin, Xiao Chen, Yun Zhao, Qing Bi, Weiguo Zou

dmPFC-vlPAG projection neurons contribute to pain maintenance thresholds and anxiolytic behaviors

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Abstract

The dorsal medial prefrontal cortex (dmPFC) has been recognized as a key cortical area for nociceptive modulation. However, the underlying neural pathway and the function of specific cell types remain largely unclear. Here, we showed that lesions of the dmPFC induced an algesic and anxious state. By using multiple tracing methods including rabies-based transsynaptic tracing method, an excitatory descending neural pathway from the dmPFC to the ventrolateral periaqueductal gray (vlPAG) was outlined. Specific activation of the dmPFC-vlPAG neural pathway by an optogenetic manipulation, produced analgesic and anxiolytic effects in a chronic pain mice model. Inhibitory neurons in the dmPFC were specifically activated by using a chemogenetic approach, which logically produced an algesic and anxious state under both normal and chronic pain conditions. Antagonists of GABAAR or mGluR1 were applied to the dmPFC, which produced analgesic and anxiolytic effects. In summary, the present results suggest that the dmPFC-vlPAG neural pathway might participate in the maintenance of pain thresholds and anxiolytic behaviors under normal conditions, while silencing or suppressing the dmPFC-vlPAG pathway might be involved in the initial stages and maintenance of chronic pain and the emergence of anxiety-like behaviors.

Authors

Jun-Bin Yin, Shao-Hua Liang, Fei Li, Wen-Jun Zhao, Yang Bai, Yi Sun, Zhen-Yu Wu, Tan Ding, Yan Sun, Hai-Xia Liu, Ya-Cheng Lu, Ting Zhang, Jing Huang, Tao Chen, Hui Li, Zhou-Feng Chen, Jing Cao, Rui Ren, Ya-Nan Peng, Juan Yang, Wei-Dong Zang, Xiang Li, Yu-Lin Dong, Yun-Qing Li

SARS-CoV-2 specific T-cell responses and correlations with COVID-19 patient predisposition

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Abstract

COVID-19 has emerged as a global pandemic caused by SARS-CoV-2. So far, viral targets of cellular immunity and factors determining successful mounting of T-cell responses are poorly defined. We therefore analyzed cellular responses to membrane, nucleocapsid and spike protein in individuals suffering from moderate or severe infection and after recovery from mild disease. We demonstrate that the CoV-2 specific CD4+ T-helper cell response is directed against all three proteins with comparable magnitude, ex vivo proliferation and portions of responding patients. However, deceased individuals were more frequently amongst non-responders. Higher patient age and comorbidity index correlated with increased frequencies of CoV-2 specific CD4+ T-cells, harboring higher portions of IL-2-, but lower portions of IFNγ secreting cells. Diminished frequencies of membrane protein reactive IFNγ+ T cells were particularly associated with higher Acute Physiology And Chronic Health Evaluation II scores in patients admitted to intensive care. CoV-2 specific T cells exhibited elevated PD-1 expression in active patients as compared to recovered individuals with previous mild disease. In summary, our data suggest a link between individual patient predisposition with respect to age and comorbidity and impairment of CoV-2 specific Th1-type cellular immunity, thereby supporting a concept of altered T-cell function in patients at risk.

Authors

Arne Sattler, Stefan Angermair, Helena Stockmann, Katrin Moira Heim, Dmytro Khadzhynov, Sascha Treskatsch, Fabian Halleck, Martin E. Kreis, Katja Kotsch

The DEL-1–β3 integrin axis promotes regulatory T cell responses during inflammation resolution

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Abstract

FOXP3+CD4+ regulatory T cells (Tregs) are critical for immune homeostasis and respond to local tissue cues, which control their stability and function. We explored here whether DEL-1, which, like Tregs, increases during resolution of inflammation, promotes Treg responses. DEL-1 enhanced Treg numbers and function at barrier sites (oral and lung mucosa). The underlying mechanism was dissected using mice lacking DEL-1 or expressing a point mutant thereof, or mice with T cell-specific deletion of the transcription factor RUNX1, identified by RNA-seq analysis of the DEL-1-induced Treg transcriptome. Specifically, through interaction with αvβ3-integrin, DEL-1 promoted induction of RUNX1-dependent FOXP3 expression and conferred stability of FOXP3 expression upon Treg restimulation in the absence of exogenous TGFβ1. Consistently, DEL-1 enhanced the demethylation of the Treg-specific demethylated region (TSDR) in the mouse Foxp3 gene and the suppressive function of sorted induced Tregs. Similarly, DEL-1 increased RUNX1 and FOXP3 expression in human conventional T cells promoting their conversion into induced Tregs with increased TSDR demethylation, enhanced stability and suppressive activity. We thus uncovered a DEL-1-αvβ3-RUNX1 axis that promotes Treg responses at barrier sites and offers novel therapeutic options for modulating inflammatory/autoimmune disorders.

Authors

Xiaofei Li, Alessandra Colamatteo, Lydia Kalafati, Tetsuhiro Kajikawa, Hui Wang, Jong-Hyung Lim, Khalil Bdeir, Kyoung-Jin Chung, Xiang Yu, Clorinda Fusco, Antonio Porcellini, Salvatore De Simone, Giuseppe Matarese, Triantafyllos Chavakis, Veronica De Rosa, George Hajishengallis

Haploidentical mixed chimerism cures autoimmunity in established type 1 diabetic mice

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Abstract

Clinical trials are currently testing whether induction of MHC-haploidentical mixed chimerism (Haplo-MC) induces organ transplantation tolerance. Whether Haplo-MC can be used to treat established autoimmune diseases remains unknown. Here, we show that established autoimmunity in euthymic and adult-thymectomized NOD (H-2g7) mice was cured by induction of Haplo-MC under a non-myeloablative anti-thymocyte globulin-based conditioning regimen and infusion of CD4+ T-depleted hematopoietic graft from H-2b/g7 F1 donors that express autoimmune-resistant H-2b or from H-2s/g7 F1 donors that express autoimmune susceptible H-2s. The cure was associated with enhanced thymic negative selection, increased thymic Treg (tTreg) production, and anergy or exhaustion of residual host-type autoreactive T cells in the periphery. The peripheral tolerance was accompanied with expansion of donor- and host-type CD62L1Helios+ tTreg as well as host-type Helios-Nrp1+ peripheral Treg (pTreg) and PD-L1hi plasmacytoid DCs (pDC). Depletion of donor- or host-type Treg cells led to reduction of host-type PD-L1hi pDCs and recurrence of autoimmunity; whereas PD-L1 deficiency in host-type DCs led to reduction of host-type pDCs and Helios-Nrp1+ pTreg cells. Thus, induction of Haplo-MC re-established both central and peripheral tolerance through mechanisms that depend on allo-MHC+ donor-type DC, PD-L1hi host-type DCs, and the generation and persistence of donor and host-type tTreg and pTreg cells.

Authors

Yuqing Liu, Xiaoqi Wang, Yongping Zhu, Mingfeng Zhang, Ubaydah Nasri, Sharne S. Sun, Stephen J. Forman, Arthur D. Riggs, Zhang Xi, Defu Zeng

EBV-induced gene 3 augments IL-23Rα protein expression through a chaperone calnexin

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Abstract

Epstein-Barr virus-induced gene 3 (EBI3) is a subunit common to IL-27, IL-35, and IL-39. Here, we explore an intracellular role of EBI3 independent of function as cytokines. EBI3-deficient naive CD4+ T cells had reduced IFN-γ production and failed to induce T cell-dependent colitis in mice. Similarly reduced IFN-γ production was observed in vitro in EBI3-deficient CD4+ T cells differentiated under pathogenic Th17 polarizing conditions with IL-23. This is because the induction of expression of one of IL-23 receptor (R) subunits, IL-23Rα, but not another IL-23R subunit, IL-12Rβ1, was selectively decreased at the protein level but not the mRNA level. EBI3 augmented IL-23Rα expression via binding to the chaperone molecule calnexin and to IL-23Rα in a peptide-dependent manner, but not glycan-dependent manner. Indeed, EBI3 failed to augment the IL-23Rα expression in the absence of endogenous calnexin. Moreover, EBI3 poorly augmented the expression of G149R, an IL-23Rα variant that protects against the development of human colitis, because binding of EBI3 to the variant was reduced. Taking together with the result that EBI3 expression is inducible in T cells, the present results suggest that EBI3 plays a critical role in augmenting IL-23Rα protein expression via calnexin under inflammatory conditions.

Authors

Izuru Mizoguchi, Mio Ohashi, Hideaki Hasegawa, Yukino Chiba, Naoko Orii, Shinya Inoue, Chiaki Kawana, Mingli Xu, Katsuko Sudo, Koji Fujita, Masahiko Kuroda, Shin-ichi Hashimoto, Kouji Matsushima, Takayuki Yoshimoto

Intestinal proinflammatory macrophages induce a phenotypic switch in interstitial cells of Cajal

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Abstract

Interstitial cells of Cajal (ICCs) are pacemaker cells in the intestine, and their function can be compromised due to loss of C-KIT expression. Macrophage activation has been identified in intestine affected by Hirschsprung disease associated enterocolitis (HAEC). In this study, we examined proinflammatory macrophage activation and explored the mechanisms by which this down-regulates C-KIT expression in ICCs in colon affected by HAEC. We found that macrophage activation and TNF-α production were dramatically increased in the proximal dilated colon of HAEC patients and 3-week old Ednrb-/- mice. Moreover, ICCs lost their C-KIT+ phenotype in the dilated colon, resulting in damaged pacemaker function and intestinal dysmotility. However, macrophage depletion or TNF-α neutralization led to recovery of ICC phenotype and restored their pacemaker function. In isolated ICCs, TNF-α-mediated phosphorylated-P65 induced over-expression of miR221, resulting in suppression of C-KIT expression and pacemaker currents. We also identified a TNF-α-NF-κB-miR221 pathway which downregulated C-KIT expression in ICCs in the colon affected by HAEC. These findings suggest the important roles of proinflammatory macrophage activation in a phenotypic switch of ICCs, representing a promising therapeutic target for HAEC.

Authors

Xuyong Chen, Xinyao Meng, Hongyi Zhang, Chenzhao Feng, Bin Wang, Ning Li, Khalid Mohamoud Abdullahi, Xiaojuan Wu, Jixin Yang, Zhi Li, Chunlei Jiao, Jia Wei, Xiaofeng Xiong, Kang Fu, Lei Yu, Gail Besner, Jiexiong Feng

Mef2d sustains activation of effector Foxp3+ Tregs during transplant survival and anticancer immunity

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Abstract

The transcription factor, Mef2d, is important in the regulation of differentiation and adaptive responses in many cell types. Among T cells, Mef2d gains new functions in Foxp3+ T-regulatory (Treg) cells as a result of its interactions with the transcription factor, Foxp3, and its release from canonical partners, like histone/protein deacetylases. Though not necessary for the generation and maintenance of Tregs, Mef2d is required for the expression of IL-10, Ctla-4 and Icos, and for the acquisition of an effector Treg phenotype. At these loci, Mef2d acts both synergistically and additively to Foxp3, and down-stream of Blimp1. Mice with the conditional deletion in Tregs of the gene encoding Mef2d are unable to maintain long-term allograft survival despite costimulation blockade and have enhanced antitumor immunity in syngeneic models, but they display only minor evidence of autoimmunity when maintained under normal conditions. The role played by Mef2d in sustaining effector Foxp3+ Treg functions without abrogating their basal actions suggests its suitability for drug discovery efforts in cancer therapy.

Authors

Eros Di Giorgio, Liqing Wang, Yan Xiong, Tatiana Akimova, Lanette M. Christensen, Rongxiang Han, Arabinda Samanta, Matteo Trevisanut, Tricia R. Bhatti, Ulf H. Beier, Wayne W. Hancock