Biology subjects

Caliz, A. D.

Publications and source records attributed to Caliz, A. D..

4 recordsLinked to original sources

bioRxiv2023

TNF-alpha promotes cilia elongation via Mixed Lineage Kinases signaling.

The primary cilium is characteristic of most of non-immune cells and acts as an environmental signal transduction sensor. The defects in primary cilium have profound consequences on the developmental program, including the maturation of retinal epithelium. The ciliary length is tightly regulated during ciliogenesis. Additionally, many features of ciliogenesis are shared with an immune synapse formation. While the interaction between the cells within an immune synapse is well-characterized, the impact of inflammatory stresses on ciliogenesis in non-immune cells remains elusive. The current study investigates the outcome of inflammatory stimuli for the primary cilium in human retinal epithelial cells. Here, we report that the exposure of retinal epithelium cells to pro-inflammatory cytokine TNF-alpha elongates cilia in a Mixed-Lineage Kinase (MLK) - dependent manner. In contrast, febrile condition-mimicking heat stress dramatically reduced the number of ciliated cells regardless of TNF-alpha exposure, suggesting distinct but rapid effects of inflammatory stresses on ciliogenesis.

cell biology↗

bioRxiv2023

Inflammatory stress-mediated chromatin changes underlie dysfunction in endothelial cells.

Inflammatory stresses underlie endothelial dysfunction and contribute to the development of chronic cardiovascular disorders such as atherosclerosis and vascular fibrosis. The initial transcriptional response of endothelial cells to pro-inflammatory cytokines such as TNF-alpha is well established. However, very few studies uncover the effects of inflammatory stresses on chromatin architecture. We used integrative analysis of ATAC-seq and RNA-seq data to investigate chromatin alterations in human endothelial cells in response to TNF-alpha and febrile-range heat stress exposure. Multi-omics data analysis suggests a correlation between the transcription of stress-related genes and endothelial dysfunction drivers with chromatin regions exhibiting differential accessibility. Moreover, microscopy identified the dynamics in the nuclear organization, specifically, the changes in a subset of heterochromatic nucleoli-associated chromatin domains, the centromeres. Upon inflammatory stress exposure, the centromeres decreased association with nucleoli in a p38-dependent manner and increased the number of transcripts from pericentromeric regions. Overall, we provide two lines of evidence that suggest chromatin alterations in vascular endothelial cells during inflammatory stresses.

genomics↗

bioRxiv2021

Mitogen Kinase Kinase (MKK7) controls cytokine production in vitro and in vivo in mice

Mitogen kinase kinase 4 (MKK4) and Mitogen kinase kinase 7 (MKK7) are members of the MAP2K family which can activate downstream mitogen-activated protein kinases (MAPKs). MKK4 has been implicated in the activation of both, c-Jun N-terminal Kinase (JNK) and p38 MAPK, whereas MKK7 only activates JNK in response to different stimuli. The stimuli as well as cell type determine the choice of MAP2K member that mediates the response. In a variety of cell types, the MKK7 contributes to the activation of downstream MAPKs, JNK, which is known to regulate essential cellular processes, such as cell death, differentiation, stress response, and cytokine secretion. Previous studies have implicated the role of MKK7 in stress signaling pathways and cytokine production. However, little is known about the degree to which MKK7 and MKK4 contributes to innate immune response in macrophages as well as during inflammation in vivo. To address this question and elucidate the role of MKK7 and MKK4 in macrophage and in vivo, we developed MKK7- and MKK4-deficient mouse models with tamoxifen-inducible Rosa26 CreERT. This study reports that MKK7 is required for JNK activation both in vitro and in vivo. Additionally, we demonstrated that MKK7 in macrophages is necessary for LPS induced cytokine production and migration which appears to be a major contributor to the inflammatory response in vivo. Whereas MKK4 plays a significant but minor role in cytokine production in vivo.

biochemistry↗

bioRxiv2021

PGC1α Regulates the Endothelial Response to Fluid Shear Stress via Telomerase Reverse Transcriptase Control of Heme Oxygenase-1

Fluid shear stress (FSS) is known to mediate multiple phenotypic changes in the endothelium. Laminar FSS (undisturbed flow) is known to promote endothelial alignment to flow that is key to stabilizing the endothelium and rendering it resistant to atherosclerosis and thrombosis. The molecular pathways responsible for endothelial responses to FSS are only partially understood. Here we have identified peroxisome proliferator gamma coactivator-1 (PGC-1) as a flow-responsive gene required for endothelial flow alignment in vitro and in vivo. Compared to oscillatory FSS (disturbed flow) or static conditions, laminar FSS (undisturbed flow) increased PGC-1 expression and its transcriptional co-activation. PGC-1 was required for laminar FSS-induced expression of telomerase reverse transcriptase (TERT) in vitro and in vivo via its association with ERR and KLF4 on the TERT promoter. We found that TERT inhibition attenuated endothelial flow alignment, elongation, and nuclear polarization in response to laminar FSS in vitro and in vivo. Among the flow-responsive genes sensitive to TERT status was heme oxygenase-1 (HMOX1), a gene required for endothelial alignment to laminar FSS. Thus, these data suggest an important role for a PGC-1-TERT-HMOX1 axis in the endothelial stabilization response to laminar FSS.

cell biology↗