Loss of Wiz Function Affects Methylation Pattern in Palate Development and Leads to Cleft Palate

WIZ (Widely Interspaced Zinc Finger) is associated with the G9a-GLP protein complex, a key H3K9 methyltransferase suggesting a role in transcriptional repression. However, its role in embryonic development is poorly described. In order to assess the loss of function of WIZ, we generated CRISPR/Cas9 WIZ knockout mouse model with 32 nucleotide deletion. Observing the lethality status, we identified the WIZ knockouts to be subviable during embryonic development and non-viable after birth. Morphology of developing embryo was analyzed at E14.5 and E18.5 and our findings were supported by microCT scans. Wiz KO showed improper development in multiple aspects, specifically in the craniofacial area. In particular, shorter snout, cleft palate, and cleft eyelids were present in mutant embryos. Palatal shelves were hypomorphic and though elevated to a horizontal position on top of the tongue, they failed to make contact and fuse. By comparison of proliferation pattern and histone methylation in developing palatal shelves we brought new evidence of importance WIZ dependent G9a-GLP methylation complex in craniofacial development, especially in palate shelf fusion.

Myopia disease mouse models: a missense point mutation (S673G) and a protein-truncating mutation of the Zfp644 mimic human disease phenotype

Zinc finger 644 (Zfp644 in mouse, ZNF644 in human) gene is a transcription factor whose mutation S672G is considered a potential genetic factor of inherited high myopia. ZNF644 interacts with G9a/GLP complex, which functions as a H3K9 methyltransferase to silence transcription. In this study, we generated mouse models to unravel the mechanisms leading to symptoms associated with high myopia. Employing TALEN technology, two mice mutants were generated, either with the disease-carrying mutation (Zfp644^S673G) or with a truncated form of Zfp644 (Zfp644^Δ8). Eye morphology and visual functions were analysed in both mutants, revealing a significant difference in a vitreous chamber depth and lens diameter, however the physiological function of retina was preserved as found under the high-myopia conditions. Our findings prove that ZNF644/Zfp644 is involved in the development of high-myopia, indicating that mutations such as, Zfp644^S673G and Zfp644^Δ8 are causative for changes connected with the disease. The developed models represent a valuable tool to investigate the molecular basis of myopia pathogenesis and its potential treatment.

Knockout of Tmem70 alters biogenesis of ATP synthase and leads to embryonal lethality in mice

TMEM70, a 21-kDa protein localized in the inner mitochondrial membrane, has been shown to facilitate the biogenesis of mammalian F1Fo ATP synthase. Mutations of the TMEM70 gene represent the most frequent cause of isolated ATP synthase deficiency resulting in a severe mitochondrial disease presenting as neonatal encephalo-cardiomyopathy (OMIM 604273). To better understand the biological role of this factor, we generated Tmem70-deficient mice and found that the homozygous Tmem70-/- knockouts exhibited profound growth retardation and embryonic lethality at ∼9.5 days post coitum. Blue-Native electrophoresis demonstrated an isolated deficiency in fully assembled ATP synthase in the Tmem70-/- embryos (80% decrease) and a marked accumulation of F1 complexes indicative of impairment in ATP synthase biogenesis that was stalled at the early stage, following the formation of F1 oligomer. Consequently, a decrease in ADP-stimulated State 3 respiration, respiratory control ratio and ATP/ADP ratios, indicated compromised mitochondrial ATP production. Tmem70-/- embryos exhibited delayed development of the cardiovascular system and a disturbed heart mitochondrial ultrastructure, with concentric or irregular cristae structures. Tmem70+/- heterozygous mice were fully viable and displayed normal postnatal growth and development of the mitochondrial oxidative phosphorylation system. Nevertheless, they presented with mild deterioration of heart function. Our results demonstrated that Tmem70 knockout in the mouse results in embryonic lethality due to the lack of ATP synthase and impairment of mitochondrial energy provision. This is analogous to TMEM70 dysfunction in humans and verifies the crucial role of this factor in the biosynthesis and assembly of mammalian ATP synthase.

KLK5 and KLK7 Ablation Fully Rescues Lethality of Netherton Syndrome-Like Phenotype

Netherton syndrome (NS) is a severe skin disease caused by the loss of protease inhibitor LEKTI, which leads to the dysregulation of epidermal proteases and severe skin-barrier defects. KLK5 was proposed as a major protease in NS pathology, however its inactivation is not sufficient to rescue the lethal phenotype of LEKTI-deficient mice. In this study, we further elucidated the in vivo roles of the epidermal proteases in NS using a set of mouse models individually or simultaneously deficient for KLK5 and KLK7 on the genetic background of a novel NS-mouse model. We show that although the ablation of KLK5 or KLK7 is not sufficient to rescue the lethal effect of LEKTI-deficiency simultaneous deficiency of both KLKs completely rescues the epidermal barrier and the postnatal lethality allowing mice to reach adulthood with fully functional skin and normal hair growth. We report that not only KLK5 but also KLK7 plays an important role in the inflammation and defective differentiation in NS and KLK7 activity is not solely dependent on activation by KLK5. Altogether, these findings show that unregulated activities of KLK5 and KLK7 are responsible for NS development and both proteases should become targets for NS therapy.

MMP-19 deficiency causes aggravation of colitis due to defects in innate immune cell function

Matrix metalloproteinases (MMPs) are potential biomarkers for disease activity in inflammatory bowel disease (IBD). However, clinical trials targeting MMPs have not succeeded, likely due to poor understanding of the biological functions of individual MMPs. Here, we explore the role of MMP-19 in IBD pathology. Using a DSS-induced model of colitis, we show evidence for increased susceptibility of Mmp-19-deficient (Mmp-19(-/-)) mice to colitis. Absence of MMP-19 leads to significant disease progression, with reduced survival rates, severe tissue destruction, and elevated levels of pro-inflammatory modulators in the colon and plasma, and failure to resolve inflammation. There was a striking delay in neutrophil infiltration into the colon of Mmp-19(-/-) mice during the acute colitis, leading to persistent inflammation and poor recovery; this was rescued by reconstitution of irradiated Mmp-19(-/-) mice with wild-type bone marrow. Additionally, Mmp-19-deficient macrophages exhibited decreased migration in vivo and in vitro and the mucosal barrier appeared compromised. Finally, chemokine fractalkine (CX3CL1) was identified as a novel substrate of MMP-19, suggesting a link between insufficient processing of CX3CL1 and cell recruitment in the Mmp-19(-/-) mice. MMP-19 proves to be a critical factor in balanced host response to colonic pathogens, and for orchestrating appropriate innate immune response in colitis.

Matrix metalloproteinase-19 inhibits growth of endothelial cells by generating angiostatin-like fragments from plasminogen

Background

Angiogenesis is the process of forming new blood vessels from existing ones and requires degradation of the vascular basement membrane and remodeling of extracellular matrix (ECM) in order to allow endothelial cells to migrate and invade into the surrounding tissue. Matrix metalloproteinases (MMPs) are considered to play a central role in the remodeling of basement membranes and ECM. However, MMPs contribute to vascular remodeling not only by degrading ECM components. Specific MMPs enhance angiogenesis via several ways; they help pericytes to detach from vessels undergoing angiogenesis, release ECM-bound angiogenic growth factors, expose cryptic pro-angiogenic integrin binding sites in the ECM, generate promigratory ECM component fragments, and cleave endothelial cell-cell adhesions. MMPs can also negatively influence the angiogenic process through generating endogenous angiogenesis inhibitors by proteolytic cleavage. Angiostatin, a proteolytic fragment of plasminogen, is one of the most potent antagonists of angiogenesis that inhibits migration and proliferation of endothelial cells. Reports have shown that metalloelastase, pancreas elastase, plasmin reductase, and plasmin convert plasminogen to angiostatin.

Results

We report here that MMP-19 processes human plasminogen in a characteristic cleavage pattern to generate three angiostatin-like fragments with a molecular weight of 35, 38, and 42 kDa. These fragments released by MMP-19 significantly inhibited the proliferation of HMEC cells by 27% (p = 0.01) and reduced formation of capillary-like structures by 45% (p = 0.05) compared with control cells. As it is known that angiostatin blocks hepatocyte growth factor (HGF)-induced pro-angiogenic signaling in endothelial cells due to structural similarities to HGF, we have analyzed if the plasminogen fragments generated by MMP-19 interfere with this pathway. As it involves the activation of c-met, the receptor of HGF, we could show that MMP-19-dependent processing of plasminogen decreases the phosphorylation of c-met.

Conclusion

Altogether, MMP-19 exhibits an anti-angiogenic effect on endothelial cells via generation of angiostatin-like fragments.

MMP19 is essential for T cell development and T cell-mediated cutaneous immune responses

Matrix metalloproteinase-19 (MMP19) affects cell proliferation, adhesion, and migration in vitro but its physiological role in vivo is poorly understood. To determine the function of MMP19, we generated mice deficient for MMP19 by disrupting the catalytic domain of mmp19 gene. Although MMP19-deficient mice do not show overt developmental and morphological abnormalities they display a distinct physiological phenotype. In a model of contact hypersensitivity (CHS) MMP19-deficient mice showed impaired T cell-mediated immune reaction that was characterized by limited influx of inflammatory cells, low proliferation of keratinocytes, and reduced number of activated CD8(+) T cells in draining lymph nodes. In the inflamed tissue, the low number of CD8(+) T cells in MMP19-deficient mice correlated with low amounts of proinflammatory cytokines, especially lymphotactin and interferon-inducible T cell alpha chemoattractant (I-TAC). Further analyses showed that T cell populations in the blood of immature, unsensitized mice were diminished and that this alteration originated from an altered maturation of thymocytes. In the thymus, thymocytes exhibited low proliferation rates and the number of CD4(+)CD8(+) double-positive cells was remarkably augmented. Based on the phenotype of MMP19-deficient mice we propose that MMP19 is an important factor in cutaneous immune responses and influences the development of T cells.

Matrix metalloproteinase-19 expression in keratinocytes is repressed by transcription factors Tst-1 and Skn-1a: implications for keratinocyte differentiation

Matrix metalloproteinase-19 (MMP-19), unlike other members of the MMP family, is expressed in basal keratinocytes of intact epidermis whereas keratinocytes in suprabasal and higher epidermal layers express this enzyme only during cutaneous disorders. As the activity of MMP-19 effects proliferation, migration, and adhesion of keratinocytes we examined whether transcription factors involved in keratinocyte differentiation repress the expression of MMP-19. Using luciferase reporter assays, POU transcription factors Tst-1 (Oct-6) and Skn-1a (Oct-11) markedly downregulated the activity of MMP-19 promoter in COS-7 cells and HaCaT keratinocytes. Tst-1 alone was able to inhibit 85% of the promoter activity. Skn-1a exhibited a weak inhibitory effect although it synergistically increased effects of Tst-1. HaCaT cells stably transfected with Tst-1 showed a strong decrease of activity of MMP-19 promoter that correlated with suppression of MMP-19, cytokeratin 14 and 5, decreased cell proliferation, and altered expression of involucrin and loricrin. The expression of MMP-9 was also significantly reduced in Tst-1 expressing keratinocytes. MMP-2 was substantially affected during its activation whereas the expression of MMP-28 was unchanged. Our results suggest that Tst-1 and Skn-1a regulate expression of MMPs in keratinocytes and effect both the expression and activation of these proteolytic enzymes.

Gender differences in achievement motive: a facet analysis of Hungarian samples

We devised an achievement motive questionnaire (Elizur 1979, 1986; Shye 1978a) based on a facet definition of achievement motive. We then administered it to 165 women and 362 men employed by a large industrial corporation in Hungary in order to examine achievement motivation. Although we found significant differences in the frequency of responses to the achievement motive items, the basic structure of the achievement motive domain was similar for women and men. We detected no special tendency for women to score higher than men on affective responses. These results support the view that gender differences in achievement motive are rooted in socialization processes rather than in basic differences between women and men.