ZEB1 promotes pathogenic Th1 and Th17 cell differentiation in multiple sclerosis.

Inappropriate CD4+ T helper (Th) differentiation can compromise host immunity or promote autoimmune disease. To identify disease-relevant regulators of T cell fate, we examined mutations that modify risk for multiple sclerosis (MS), a canonical organ-specific autoimmune disease. This analysis identified a role for Zinc finger E-box-binding homeobox (ZEB1). Deletion of ZEB1 protects against experimental autoimmune encephalitis (EAE), a mouse model of multiple sclerosis (MS). Mechanistically, ZEB1 in CD4+ T cells is required for pathogenic Th1 and Th17 differentiation. Genomic analyses of paired human and mouse expression data elucidated an unexpected role for ZEB1 in JAK-STAT signaling. ZEB1 inhibits miR-101-3p that represses JAK2 expression, STAT3/STAT4 phosphorylation, and subsequent expression of interleukin-17 (IL-17) and interferon gamma (IFN-γ). Underscoring its clinical relevance, ZEB1 and JAK2 downregulation decreases pathogenic cytokines expression in T cells from MS patients. Moreover, a Food and Drug Administration (FDA)-approved JAK2 inhibitor is effective in EAE. Collectively, these findings identify a conserved, potentially targetable mechanism regulating disease-relevant inflammation.

Inactivation of endothelial ZEB1 impedes tumor progression and sensitizes tumors to conventional therapies.

Current antiangiogenic therapy is limited by its cytostatic property, scarce drug delivery to the tumor, and side toxicity. To address these limitations, we unveiled the role of ZEB1, a tumor endothelium-enriched zinc-finger transcription factor, during tumor progression. We discovered that the patients who had lung adenocarcinomas with high ZEB1 expression in tumor endothelium had increased prevalence of metastases and markedly reduced overall survival after the diagnosis of lung cancer. Endothelial ZEB1 deletion in tumor-bearing mice diminished tumor angiogenesis while eliciting persistent tumor vascular normalization by epigenetically repressing TGF-ß signaling. This consequently led to improved blood and oxygen perfusion, enhanced chemotherapy delivery and immune effector cell infiltration, and reduced tumor growth and metastasis. Moreover, targeting vascular ZEB1 remarkably potentiated the anticancer activity of nontoxic low-dose cisplatin. Treatment with low-dose anti-programmed cell death protein 1 (anti-PD-1) antibody elicited tumor regression and markedly extended survival in ZEB1-deleted mice, conferring long-term protective anticancer immunity. Collectively, we demonstrated that inactivation of endothelial ZEB1 may offer alternative opportunities for cancer therapy with minimal side effects. Targeting endothelium-derived ZEB1 in combination with conventional chemotherapy or immune checkpoint blockade therapy may yield a potent and superior anticancer effect.

ZEBs: Novel Players in Immune Cell Development and Function.

ZEB1 and ZEB2 are zinc-finger E homeobox-binding transcription factors best known for their role in driving epithelial to mesenchymal transition. However, in recent years our understanding of these two transcription factors has broadened, and it is now clear that they are expressed by a variety of immune cells of both myeloid and lymphoid lineages, including dendritic cells, macrophages, monocytes, B, T, and NK cells. In these cells, ZEBs function to regulate important transcriptional networks necessary for cell differentiation, maintenance, and function. Here, we review the current understanding of ZEB regulation across immune cell lineages, particularly in mice, highlighting present gaps in our knowledge. We also speculate on important questions for the future.

ZEB1 protects skeletal muscle from damage and is required for its regeneration.

The mechanisms linking muscle injury and regeneration are not fully understood. Here we report an unexpected role for ZEB1 regulating inflammatory and repair responses in dystrophic and acutely injured muscles. ZEB1 is upregulated in the undamaged and regenerating myofibers of injured muscles. Compared to wild-type counterparts, Zeb1-deficient injured muscles exhibit enhanced damage that corresponds with a retarded p38-MAPK-dependent transition of their macrophages towards an anti-inflammatory phenotype. Zeb1-deficient injured muscles also display a delayed and poorer regeneration that is accounted by the retarded anti-inflammatory macrophage transition and their intrinsically deficient muscle satellite cells (MuSCs). Macrophages in Zeb1-deficient injured muscles show lower phosphorylation of p38 and its forced activation reverts the enhanced muscle damage and poorer regeneration. MuSCs require ZEB1 to maintain their quiescence, prevent their premature activation following injury, and drive efficient regeneration in dystrophic muscles. These data indicate that ZEB1 protects muscle from damage and is required for its regeneration.

Loss of the candidate tumor suppressor ZEB1 (TCF8, ZFHX1A) in Sézary syndrome.

Cutaneous T-cell lymphoma is a group of incurable extranodal non-Hodgkin lymphomas that develop from the skin-homing CD4+ T cell. Mycosis fungoides and Sézary syndrome are the most common histological subtypes. Although next-generation sequencing data provided significant advances in the comprehension of the genetic basis of this lymphoma, there is not uniform consensus on the identity and prevalence of putative driver genes for this heterogeneous group of tumors. Additional studies may increase the knowledge about the complex genetic etiology characterizing this lymphoma. We used SNP6 arrays and GISTIC algorithm to prioritize a list of focal somatic copy-number alterations in a dataset of multiple sequential samples from 21 Sézary syndrome patients. Our results confirmed a prevalence of significant focal deletions over amplifications: single well-known tumor suppressors, such as TP53, PTEN, and RB1, are targeted by these aberrations. In our cohort, ZEB1 (TCF8, ZFHX1A) spans a deletion having the highest level of significance. In a larger group of 43 patients, we found that ZEB1 is affected by deletions and somatic inactivating mutations in 46.5% of cases; also, we found potentially relevant ZEB1 germline variants. The survival analysis shows a worse clinical course for patients with ZEB1 biallelic inactivation. Multiple abnormal expression signatures were found associated with ZEB1 depletion in Sézary patients we verified that ZEB1 exerts a role in oxidative response of Sézary cells. Our data confirm the importance of deletions in the pathogenesis of cutaneous T-cell lymphoma. The characterization of ZEB1 abnormalities in Sézary syndrome fulfils the criteria of a canonical tumor suppressor gene. Although additional confirmations are needed, our findings suggest, for the first time, that ZEB1 germline variants might contribute to the risk of developing this disease. Also, we provide evidence that ZEB1 activity in Sézary cells, influencing the reactive oxygen species production, affects cell viability and apoptosis.

Importance of EMT Factor ZEB1 in cDC1 "MutuDC Line" Mediated Induction of Th1 Immune Response.

The role of Epithelial to Mesenchymal Transition (EMT) factor Zeb1 is well defined in metastasis and cancer progression but it's importance in dendritic cells (DCs) is unexplored until now. For the first time we report here that Zeb1 controls immunogenic responses of CD8α+ conventional Type-I (cDC1) DCs. We found that ZEB1 expression increases significantly after TLR9 stimulation and its depletion impairs activation, co-stimulation and secretion of important cytokines like IL-6, IL-10 and IL-12 in cDC1 MutuDC line. We further confirmed our findings in primary cDC1 DCs derived from bone marrow. Co-culture of these Zeb1 knock down (KD) DCs with OT-II CD4+ T helper cells skewed their differentiation toward Th2 subtype. Moreover, adoptive transfer of activated Zeb1 KD DCs cleared intestinal worms in helminth infected mice by increasing Th2 responses in vivo. Integrative genomic analysis showed Zeb1 as an activator of immune response genes in cDC1 MutuDCs as compared to other pathway genes. In addition, differentially regulated genes in Zeb1 KD RNA-seq showed significant enrichment of Th2 activation pathways supporting our in vitro findings. Mechanistically, we showed that decreased IL-12 secreted by Zeb1 KD DCs is the plausible mechanism for increased Th2 differentiation. Collectively our data demonstrate that Zeb1 could be targeted in DCs to modulate T-cell mediated adaptive immune responses.

Upregulation of Microglial ZEB1 Ameliorates Brain Damage after Acute Ischemic Stroke.

Microglia are a key immune-competent cell type that respond to environmental and physiological changes during ischemic stroke. However, the molecular mechanisms controlling post-ischemic microglia activity are unclear. Understanding these mechanisms may ultimately reduce disease burden and allow the manipulation of microglia responses to shape the outcomes of stroke. Here, we report that, after experimentally induced stroke, ZEB1 is highly expressed in ipsilateral cerebral hemisphere, where it is upregulated mainly in microglia. Using a conditional transgenic mouse, we found that ZEB1 upregulation in microglia regulates immune responses in the CNS and alleviates brain injury after ischemic stroke. Our data indicate that ZEB1 overexpression mediates microglia responses and, in turn, inhibits the production of astrocytic CXCL1 through the TGF-ß1-dependent pathway. Reduced CXCL1 leads to a decline in neutrophil infiltration into the brain, thereby reducing CNS inflammation. Our results demonstrate the importance of ZEB1 in microglia-orchestrated neuroinflammation and suggest a potential means for reducing stroke-induced neurological injury.