19 research outputs found
Phenotypical microRNA screen reveals a noncanonical role of CDK2 in regulating neutrophil migration
Neutrophil migration is essential for inflammatory responses to kill pathogens; however, excessive neutrophilic inflammation also leads to tissue injury and adverse effects. To discover novel therapeutic targets that modulate neutrophil migration, we performed a neutrophil-specific microRNA (miRNA) overexpression screen in zebrafish and identified 8 miRNAs as potent suppressors of neutrophil migration. Among those, miR-199 decreases neutrophil chemotaxis in zebrafish and human neutrophil-like cells. Intriguingly, in terminally differentiated neutrophils, miR-199 alters the cell cycle-related pathways and directly suppresses cyclin-dependent kinase 2 (Cdk2), whose known activity is restricted to cell cycle progression and cell differentiation. Inhibiting Cdk2, but not DNA replication, disrupts cell polarity and chemotaxis of zebrafish neutrophils without inducing cell death. Human neutrophil-like cells deficient in CDK2 fail to polarize and display altered signaling downstream of the formyl peptide receptor. Chemotaxis of primary human neutrophils is also reduced upon CDK2 inhibition. Furthermore, miR-199 overexpression or CDK2 inhibition significantly improves the outcome of lethal systemic inflammation challenges in zebrafish. Our results therefore reveal previously unknown functions of miR-199 and CDK2 in regulating neutrophil migration and provide directions in alleviating systemic inflammation
The ENTH domain protein Clint1 is required for epidermal homeostasis in zebrafish
Epidermal hyperproliferation and inflammation are hallmarks of the human
condition psoriasis. Here, we report that a zebrafish line with a mutation in
the cargo adaptor protein Clint1 exhibits psoriasis-like phenotypes including
epithelial hyperproliferation and leukocyte infiltration. Clint1 is an ENTH
domain-containing protein that binds SNARE proteins and functions in vesicle
trafficking; however, its in vivo function in animal models has not been
reported to date. The clint1 mutants exhibit chronic inflammation
characterized by increased Interleukin 1β expression, leukocyte
infiltration, bidirectional trafficking and phagocytosis of cellular debris.
The defects in clint1 mutants can be rescued by expression of
zebrafish clint1 and can be phenocopied with clint1-specific
morpholinos, supporting an essential role for Clint1 in epidermal development.
Interaction studies suggest that Clint1 and Lethal giant larvae 2 function
synergistically to regulate epidermal homeostasis. Accordingly,
clint1 mutants show impaired hemidesmosome formation, loss of
cell-cell contacts and increased motility suggestive of epithelial to
mesenchymal transition. Taken together, our findings describe a novel function
for the ENTH domain protein Clint1 in epidermal development and inflammation
and suggest that its deficiency in zebrafish generates a phenotype that
resembles the human condition psoriasis