Toxoplasma Cathepsin Protease B and Aspartyl Protease 1 play recessive roles in endolysosomal protein digestion during infection

ABSTRACT The lysosome-like vacuolar compartment (VAC) is a major site of proteolysis in the intracellular parasite Toxoplasma gondii. Previous studies have shown that genetic ablation of a VAC-residing cysteine protease, cathepsin protease L (CPL), resulted in the accumulation of undigested protein in the VAC and loss of parasite viability during the chronic stage of infection. However, since the maturation of another VAC localizing protease, cathepsin protease B (CPB), is dependent on CPL, it remained unknown whether these defects result directly from ablation of CPL or indirectly from a lack of CPB maturation. Likewise, although a previously described cathepsin D-like aspartyl protease 1 (ASP1) could also play a role in proteolysis, its definitive residence and function in the Toxoplasma endolysosomal system were not well defined. Here, we demonstrate that CPB is not necessary for protein turnover in the VAC and that CPB-deficient parasites have normal growth and viability in both the acute and chronic stages of infection. We also show that ASP1 depends on CPL for correct maturation, and it resides in the T. gondii VAC, where, similar to CPB, it plays a dispensable role in protein digestion. Taken together with previous work, our findings suggest that CPL is the dominant protease in a hierarchy of proteolytic enzymes within the VAC. This unusual lack of redundancy for CPL in T. gondii makes it a single exploitable target for disrupting chronic toxoplasmosis. IMPORTANCE Roughly one-third of the human population is chronically infected with the intracellular single-celled parasite Toxoplasma gondii, but little is known about how this organism persists inside people. Previous research suggested that a parasite proteolytic enzyme, termed cathepsin protease L, is important for Toxoplasma persistence; however, it remained possible that other associated proteolytic enzymes could also be involved in the long-term survival of the parasite during infection. Here, we show that two proteolytic enzymes associated with cathepsin protease L play dispensable roles and are dependent on cathepsin L to reach maturity, which differs from the corresponding enzymes in humans. These findings establish a divergent hierarchy of proteases and help focus attention principally on cathepsin protease L as a potential target for interrupting Toxoplasma chronic infection.

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p38δ genetic ablation protects female mice from anthracycline cardiotoxicity

10.1101/2020.03.02.973347 ◽

2020 ◽

Author(s):

Sharon A George ◽

Alexi Kiss ◽

Sofian N Obaid ◽

Aileen Venegas ◽

Trisha Talapatra ◽

...

Keyword(s):

Cardiac Injury ◽

Mapk Signaling ◽

Anthracycline Cardiotoxicity ◽

Genetic Ablation ◽

Female Mice ◽

Echocardiographic Parameters ◽

The Individual ◽

And Function ◽

First Time ◽

Dose Dependent

ABSTRACTBACKGROUNDThe efficacy of an anthracycline antibiotic doxorubicin (DOX) as a chemotherapeutic agent is limited by dose-dependent cardiotoxicity. DOX is associated with activation of intracellular stress signaling pathways including p38 MAPKs. While previous studies have implicated p38 MAPK signaling in DOX-induced cardiac injury, the roles of the individual p38 isoforms, specifically, of the alternative isoforms p38γ and p38δ, remain uncharacterized.OBJECTIVESTo determine the potential cardioprotective effects of p38γ and p38δ genetic deletion in mice subjected to acute DOX treatment.METHODSMale and female wild-type (WT), p38γ-/-, p38δ-/- and p38γ-/-δ-/- mice were injected with 30 mg/kg DOX and their survival was tracked for ten days. During this period cardiac function was assessed by echocardiography and electrocardiography and fibrosis by PicroSirius Red staining. Immunoblotting was performed to assess the expression of signaling proteins and markers linked to autophagy.RESULTSSignificantly improved survival was observed in p38δ-/- female mice post-DOX relative to WT females, but not in p38γ-/- or p38γ-/-δ-/- male or female mice. The improved survival in DOX-treated p38δ-/- females was associated with decreased fibrosis, increased cardiac output and LV diameter relative to DOX-treated WT females, and similar to saline-treated controls. Structural and echocardiographic parameters were either unchanged or worsened in all other groups. Increased autophagy, as evidenced by increased LC3-II level, and decreased mTOR activation was also observed in DOX-treated p38δ-/- females.CONCLUSIONSp38δ plays a crucial role in promoting DOX-induced cardiotoxicity in female mice by inhibiting autophagy. Therefore, p38δ targeting could be a potential cardioprotective strategy in anthracycline chemotherapy.NEW AND NOTEWORTHYThis study for the first time identifies the roles of the alternative p38γ and p38δ MAPK isoforms in promoting DOX-cardiotoxicity in a sex-specific manner. While p38γ systemic deletion did not affect DOX-cardiotoxicity, p38δ systemic deletion was cardioprotective in female but not in male mice. Cardiac structure and function were preserved in DOX-treated p38δ-/- females and autophagy was increased.

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Considerations of the Occurrence, Structure and Function of the Proteolytic Enzymes of the Pancreas

Ciba Foundation Symposium - The Exocrine Pancreas: Normal and Abnormal Functions - Novartis Foundation Symposia ◽

10.1002/9780470719268.ch4 ◽

2008 ◽

pp. 67-89

Author(s):

Hans Neurath

Keyword(s):

Proteolytic Enzymes ◽

Structure And Function ◽

And Function

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Exploring the Relationship between Forest Structure and Health

Forests ◽

10.3390/f11121264 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1264

Author(s):

Jinki Kim ◽

Duk-Byeong Park ◽

Jung Il Seo

Keyword(s):

Mental Health ◽

Physical Activity ◽

Landscape Metrics ◽

Forest Structure ◽

Normal Growth ◽

Urban Neighborhood ◽

Forest Patches ◽

Forest Patch ◽

Irregular Shapes ◽

And Function

There is abundant evidence that green space in urban neighborhood is associated with physical activity and it is well known that physical activity contributes to human health. Physical activity fosters normal growth and development, can reduce the risk of chronic diseases, and can make people feel better and function better. Evidences also show that exposure to natural places can lead to positive mental health outcomes, whether a view of nature from a window, being within natural places, or exercising in these environments. The study aims to identify the factors of forest structure and socioeconomic characteristics influencing adults’ physical activity and health. A sample of 148,754 respondents from the Korea Community Health Survey, conducted in 2016, was analyzed. Measures included frequency of physical activity, stress, depression, and landscape metrics of forest patch. Hierarchical multiple regression analysis, controlling for socio-demographic characteristics, revealed that larger forest patches and the more irregular shapes were associated with more physical activity. The study also showed that the shape of forest patch and slope were associated with less mental health complaints, whereas composition related landscape metrics were not.

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A Method for Determining the Strain-Time Endurance of Cells in Planar Tissue-Engineered Constructs Subjected to Large Compressive Deformations

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192322 ◽

2008 ◽

Author(s):

Amit Gefen ◽

Bastiaan van Nierop ◽

Dan L. Bader ◽

Cees W. Oomens

Keyword(s):

Experimental Method ◽

Artificial Muscle ◽

Normal Growth ◽

Mechanical Environment ◽

Time Threshold ◽

Chronic Injuries ◽

Time Periods ◽

Murine Skeletal Muscle ◽

And Function ◽

Substantial Interest

The mechanical environment of cells influences their normal growth and function, and may also affect the development of diseases and chronic injuries. Accordingly, there is substantial interest in determining the endurance of cells subjected to controlled mechanical strains for given time periods. A standardized, generic experimental method for determining strain-time thresholds for cell death is so far missing in the literature. In this study, a new experimental method was developed to measure strain-time thresholds of cells in planar tissue-engineered constructs subjected to large compressive strains. The method was applied to measure a strain-time threshold for differentiated C2C12 murine skeletal muscle cells in tissue-engineered bio-artificial muscle (BAM) constructs.

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The RNAseIII enzyme Drosha is critical in T cells for preventing lethal inflammatory disease

Journal of Experimental Medicine ◽

10.1084/jem.20081219 ◽

2008 ◽

Vol 205 (9) ◽

pp. 2005-2017 ◽

Cited By ~ 255

Author(s):

Mark M.W. Chong ◽

Jeffrey P. Rasmussen ◽

Alexander Y. Rudensky ◽

Dan R. Littman

Keyword(s):

T Cell ◽

Inflammatory Disease ◽

Cell Types ◽

Mirna Biogenesis ◽

Cell Compartment ◽

Foxp3 Gene ◽

Genetic Ablation ◽

And Function ◽

Specific Deletion

MicroRNAs (miRNAs) are implicated in the differentiation and function of many cell types. We provide genetic and in vivo evidence that the two RNaseIII enzymes, Drosha and Dicer, do indeed function in the same pathway. These have previously been shown to mediate the stepwise maturation of miRNAs (Lee, Y., C. Ahn, J. Han, H. Choi, J. Kim, J. Yim, J. Lee, P. Provost, O. Radmark, S. Kim, and V.N. Kim. 2003. Nature. 425:415–419), and genetic ablation of either within the T cell compartment, or specifically within Foxp3+ regulatory T (T reg) cells, results in identical phenotypes. We found that miRNA biogenesis is indispensable for the function of T reg cells. Specific deletion of either Drosha or Dicer phenocopies mice lacking a functional Foxp3 gene or Foxp3+ cells, whereas deletion throughout the T cell compartment also results in spontaneous inflammatory disease, but later in life. Thus, miRNA-dependent regulation is critical for preventing spontaneous inflammation and autoimmunity.

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Ablation of adipose-HO-1 expression increases white fat over beige fat through inhibition of mitochondrial fusion and of PGC1α in female mice

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci-2017-0027 ◽

2017 ◽

Vol 31 (1) ◽

Cited By ~ 9

Author(s):

Shailendra P. Singh ◽

Ilana Grant ◽

Aliza Meissner ◽

Attallah Kappas ◽

Nader G. Abraham

Keyword(s):

Adipose Tissue ◽

Knockout Mouse ◽

Potential Role ◽

Mitochondrial Quality Control ◽

Knockout Mouse Model ◽

Genetic Ablation ◽

Beige Fat ◽

And Function ◽

White Fat

AbstractBackgroundHmox1 plays an important role in the regulation of mitochondrial bioenergetics and function by regulating cellular heme-derived CO and bilirubin. Previous studies have demonstrated that global disruption of HO-1 in humans and mice resulted in severe organ dysfunction.MethodsWe investigated the potential role of adipose-specific-HO-1 genetic ablation on adipose tissue function, mitochondrial quality control and energy expenditure by generating an adipo-HO-1 knockout mouse model (Adipo-HO-1ResultsAdipo-HO-1ConclusionAblation of adipose tissue-HO-1 abridged PGC1 expression promoted mitochondrial dysfunction and contributed to an increase of pro-inflammatory visceral fat and abrogated beige-cell like phenotype.

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New concepts in regulation and function of the insulin-like growth factors: implications for understanding normal growth and neoplasia

Cellular and Molecular Life Sciences ◽

10.1007/pl00000735 ◽

2000 ◽

Vol 57 (6) ◽

pp. 932-942 ◽

Cited By ~ 101

Author(s):

H. Werner ◽

D. Le Roith*

Keyword(s):

Growth Factors ◽

Normal Growth ◽

New Concepts ◽

And Function ◽

Insulin Like Growth Factors

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Type I Interferons Control Proliferation and Function of the Intestinal Epithelium

Molecular and Cellular Biology ◽

10.1128/mcb.00988-15 ◽

2016 ◽

Vol 36 (7) ◽

pp. 1124-1135 ◽

Cited By ~ 22

Author(s):

Yuliya V. Katlinskaya ◽

Kanstantsin V. Katlinski ◽

Audrey Lasri ◽

Ning Li ◽

Daniel P. Beiting ◽

...

Keyword(s):

Intestinal Epithelium ◽

Type I Interferons ◽

Type I ◽

Cell Renewal ◽

Intestinal Epithelial ◽

Barrier Dysfunction ◽

Antiproliferative Effects ◽

Genetic Ablation ◽

And Function ◽

Intestinal Hyperplasia

Wnt pathway-driven proliferation and renewal of the intestinal epithelium must be tightly controlled to prevent development of cancer and barrier dysfunction. Although type I interferons (IFN) produced in the gut under the influence of microbiota are known for their antiproliferative effects, the role of these cytokines in regulating intestinal epithelial cell renewal is largely unknown. Here we report a novel role for IFN in the context of intestinal knockout of casein kinase 1α (CK1α), which controls the ubiquitination and degradation of both β-catenin and the IFNAR1 chain of the IFN receptor. Ablation of CK1α leads to the activation of both β-catenin and IFN pathways and prevents the unlimited proliferation of intestinal epithelial cells despite constitutive β-catenin activity. IFN signaling contributes to the activation of the p53 pathway and the appearance of apoptotic and senescence markers in the CK1α-deficient gut. Concurrent genetic ablation of CK1α and IFNAR1 leads to intestinal hyperplasia, robust attenuation of apoptosis, and rapid and lethal loss of barrier function. These data indicate that IFN play an important role in controlling the proliferation and function of the intestinal epithelium in the context of β-catenin activation.

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Normal Lymphatic Development and Function in Mice Deficient for the Lymphatic Hyaluronan Receptor LYVE-1

Molecular and Cellular Biology ◽

10.1128/mcb.01503-06 ◽

2006 ◽

Vol 27 (2) ◽

pp. 595-604 ◽

Cited By ~ 144

Author(s):

Nicholas W. Gale ◽

Remko Prevo ◽

Jorge Espinosa ◽

David J. Ferguson ◽

Melissa G. Dominguez ◽

...

Keyword(s):

Lymphatic Vessels ◽

Physiological Role ◽

Normal Growth ◽

Skin Inflammation ◽

Lewis Lung ◽

Lymphatic Development ◽

Lymph Node Sinus ◽

And Function ◽

Draining Lymph Nodes ◽

Hyaluronan Receptor

ABSTRACT The hyaluronan receptor LYVE-1 is expressed abundantly on the surfaces of lymphatic vessels and lymph node sinus endothelial cells from early development, where it has been suggested to function both in cell adhesion/transmigration and as a scavenger for hyaluronan turnover. To investigate the physiological role(s) of LYVE-1, we generated mice in which the gene for the receptor was inactivated by replacement with a β-galactosidase reporter. LYVE-1−/− mice displayed an apparently normal phenotype, with no obvious alteration in lymphatic vessel ultrastructure or function and no apparent change in secondary lymphoid tissue structure or cellularity. In addition, the levels of hyaluronan in tissue and blood were unchanged. LYVE-1−/− mice also displayed normal trafficking of cutaneous CD11c+ dendritic cells to draining lymph nodes via afferent lymphatics and normal resolution of oxazolone-induced skin inflammation. Finally, LYVE-1−/− mice supported normal growth of transplanted B16F10 melanomas and Lewis lung carcinomas. These results indicate that LYVE-1 is not obligatory for normal lymphatic development and function and suggest either the existence of compensatory receptors or a role more specific than that previously envisaged.

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