121 research outputs found
Loss of Hsp70 Exacerbates Pathogenesis But Not Levels of Fibrillar Aggregates in a Mouse Model of Huntington's Disease
Endogenous protein quality control machinery has long been suspected of influencing the onset and progression of neurodegenerative diseases characterized by accumulation of misfolded proteins. Huntington's disease (HD) is a fatal neurodegenerative disorder caused by an expansion of a polyglutamine (polyQ) tract in the protein huntingtin (htt), which leads to its aggregation and accumulation in inclusion bodies. Here, we demonstrate in a mouse model of HD that deletion of the molecular chaperones Hsp70.1 and Hsp70.3 significantly exacerbated numerous physical, behavioral and neuropathological outcome measures, including survival, body weight, tremor, limb clasping and open field activities. Deletion of Hsp70.1 and Hsp70.3 significantly increased the size of inclusion bodies formed by mutant htt exon 1, but surprisingly did not affect the levels of fibrillar aggregates. Moreover, the lack of Hsp70s significantly decreased levels of the calcium regulated protein c-Fos, a marker for neuronal activity. In contrast, deletion of Hsp70s did not accelerate disease in a mouse model of infectious prion-mediated neurodegeneration, ruling out the possibility that the Hsp70.1/70.3 mice are nonspecifically sensitized to all protein misfolding disorders. Thus, endogenous Hsp70s are a critical component of the cellular defense against the toxic effects of misfolded htt protein in neurons, but buffer toxicity by mechanisms independent of the deposition of fibrillar aggregates
Cardiocutaneous syndrome is caused by aggregation of iASPP mutants
The ASPP (apoptosis-stimulating protein of p53) family of proteins is involved in many cellular interactions and is starting to emerge as a major scaffolding hub for numerous proteins involved in cancer biology, inflammation and cellular integrity. It consists of the three members ASPP1, ASPP2 and iASPP which are best known for modulating the apoptotic function of p53, thereby directing cell fate decision. Germline mutations in iASPP have been shown to cause cardiocutaneous syndromes, a combination of heart and skin defects usually leading to death before the age of five. Mutations in iASPP causing these syndromes do not cluster in hot spots but are distributed throughout the protein. To understand the molecular mechanism(s) of how mutations in iASPP cause the development of cardiocutaneous syndromes we analysed the stability and solubility of iASPP mutants, characterized their interaction with chaperones and investigated their influence on NF-ĸB activity. Here we show that three different mechanisms are responsible for loss of function of iASPP: loss of the complete C-terminal domain, mutations resulting in increased auto-inhibition and aggregation due to destabilization of the C-terminal domain. In contrast to these germline mutations causing cardiocutaneous syndromes, missense mutations found in cancer do not result in aggregation
Hsp70 and Hsp40 Functionally Interact with Soluble Mutant Huntingtin Oligomers in a Classic ATP-Dependent Reaction Cycle
Inclusion bodies of aggregated mutant huntingtin (htt) fragments are a neuropathological hallmark of Huntington disease (HD). The molecular chaperones Hsp70 and Hsp40 colocalize to inclusion bodies and are neuroprotective in HD animal models. How these chaperones suppress mutant htt toxicity is unclear but might involve direct effects on mutant htt misfolding and aggregation. Using size exclusion chromatography and atomic force microscopy, we found that mutant htt fragments assemble into soluble oligomeric species with a broad size distribution, some of which reacted with the conformation-specific antibody A11. Hsp70 associated with A11-reactive oligomers in an Hsp40- and ATP-dependent manner and inhibited their formation coincident with suppression of caspase 3 activity in PC12 cells. Thus, Hsp70 and Hsp40 (DNAJB1) dynamically target specific subsets of soluble oligomers in a classic ATP-dependent reaction cycle, supporting a pathogenic role for these structures in HD
Methylene blue modulates huntingtin aggregation intermediates and is protective in Huntingtons disease models.
Huntingtons disease (HD) is a devastating neurodegenerative disorder with no disease-modifying treatments available. The disease is caused by expansion of a CAG trinucleotide repeat and manifests with progressive motor abnormalities, psychiatric symptoms, and cognitive decline. Expression of an expanded polyglutamine repeat within the Huntingtin (Htt) protein impacts numerous cellular processes, including protein folding and clearance. A hallmark of the disease is the progressive formation of inclusions that represent the culmination of a complex aggregation process. Methylene blue (MB), has been shown to modulate aggregation of amyloidogenic disease proteins. We investigated whether MB could impact mutant Htt-mediated aggregation and neurotoxicity. MB inhibited recombinant protein aggregation in vitro, even when added to preformed oligomers and fibrils. MB also decreased oligomer number and size and decreased accumulation of insoluble mutant Htt in cells. In functional assays, MB increased survival of primary cortical neurons transduced with mutant Htt, reduced neurodegeneration and aggregation in a Drosophila melanogaster model of HD, and reduced disease phenotypes in R6/2 HD modeled mice. Furthermore, MB treatment also promoted an increase in levels of BDNF RNA and protein in vivo. Thus, MB, which is well tolerated and used in humans, has therapeutic potential for HD
Deceased donor uterus transplantation: religious perceptions
BackgroundUterus transplant now offers an alternative deceased donation treatment option for women with uterine infertility. Limited research exists on religious opinions that may impact the addition of the uterus to current multi-organ deceased donor programsObjectiveTo explore the acceptability of uterus transplantation and deceased uterus donation across different religious groups.DesignA cross-sectional survey of 2,497 participants was conducted between October 2022 and January 2023 in NSW Australia. Australia is a culturally and religiously diverse nation with over 60% of people identifying with a religion, including Christianity (43%), Islam (3.2%), Buddhism (2.7%), Hinduism (2.4%). This survey captured awareness and attitudes towards deceased uterus donation. Descriptive statistics and regression analyses were used to explore factors influencing organ donation and next-of-kin perceptions.ResultsA total of 2,497 respondents completed the survey. Christians had greater awareness of organ donation but were less likely to be registered donors, or consent to uterus donation. Those of Hindu faith were less likely to be registered organ donors. Next-of-kin from the Islamic faith were reluctant to consent to organ donation if the donor's pre-death wishes were unknown, and less likely to consent to uterus donation. Participants identifying as Buddhist had a higher awareness of uterus transplantation.ConclusionOrgan donor awareness and consent rates varied across religious groups, including for uterus donation. Differences may stem from varying beliefs about bodily integrity, and reproductive rights, which may influence attitudes toward uterus donation. Tailored culturally and linguistically sensitive educational campaigns should address the unique aspects of uterus donation
Methylene Blue Modulates Huntingtin Aggregation Intermediates and is Protective in Huntington\u27s Disease Models
Huntington\u27s disease (HD) is a devastating neurodegenerative disorder with no disease-modifying treatments available. The disease is caused by expansion of a CAG trinucleotide repeat and manifests with progressive motor abnormalities, psychiatric symptoms, and cognitive decline. Expression of an expanded polyglutamine repeat within the Huntingtin (Htt) protein impacts numerous cellular processes, including protein folding and clearance. A hallmark of the disease is the progressive formation of inclusions that represent the culmination of a complex aggregation process. Methylene blue (MB), has been shown to modulate aggregation of amyloidogenic disease proteins. We investigated whether MB could impact mutant Htt-mediated aggregation and neurotoxicity. MB inhibited recombinant protein aggregation in vitro, even when added to preformed oligomers and fibrils. MB also decreased oligomer number and size and decreased accumulation of insoluble mutant Htt in cells. In functional assays, MB increased survival of primary cortical neurons transduced with mutant Htt, reduced neurodegeneration and aggregation in a Drosophila melanogaster model of HD, and reduced disease phenotypes in R6/2 HD modeled mice. Furthermore, MB treatment also promoted an increase in levels of BDNF RNA and protein in vivo. Thus, MB, which is well tolerated and used in humans, has therapeutic potential for HD
Chemosaturation Percutaneous Hepatic Perfusion: A Systematic Review
The Hepatic CHEMOSAT(®) Delivery System is an innovative medical device for the treatment of patients with unresectable primary liver tumors or unresectable hepatic metastases from solid organ malignancies. This system is used to perform chemosaturation percutaneous hepatic perfusion (CS-PHP), a procedure in which a high dose of the chemotherapeutic agent melphalan is delivered directly to the liver while limiting systemic exposure. In a clinical trial program, CS-PHP with melphalan significantly improved hepatic progression-free survival in patients with unresectable hepatic metastases from ocular or cutaneous melanoma. Clinically meaningful hepatic responses were also observed in patients with hepatocellular carcinoma or neuroendocrine tumors. Furthermore, the results of published studies and case reports demonstrated that CS-PHP with melphalan resulted in favorable tumor response rates in a range of tumor histologies (ocular or cutaneous melanoma, colorectal cancer, and hepatobiliary tumors). Analyses of the safety profile of CS-PHP revealed that the most common adverse effects were hematologic events (thrombocytopenia, anemia, and neutropenia), which were clinically manageable. Taken together, these findings indicate that CS-PHP is a promising locoregional therapy for patients with primary and secondary liver tumors and has a acceptable safety profile. Funding: Delcath Systems Inc., New York, NY, USA
Mutant Ras and inflammation-driven skin tumorigenesis is suppressed via a JNK-iASPP-AP1 axis
Concurrent mutation of a RAS oncogene and the tumor suppressor p53 is common in tumorigenesis, and inflammation can promote RAS-driven tumorigenesis without the need to mutate p53. Here, we show, using a well-established mutant RAS and an inflammation-driven mouse skin tumor model, that loss of the p53 inhibitor iASPP facilitates tumorigenesis. Specifically, iASPP regulates expression of a subset of p63 and AP1 targets, including genes involved in skin differentiation and inflammation, suggesting that loss of iASPP in keratinocytes supports a tumor-promoting inflammatory microenvironment. Mechanistically, JNK-mediated phosphorylation regulates iASPP function and inhibits iASPP binding with AP1 components, such as JUND, via PXXP/SH3 domain-mediated interaction. Our results uncover a JNK-iASPP-AP1 regulatory axis that is crucial for tissue homeostasis. We show that iASPP is a tumor suppressor and an AP1 coregulator
CEERS Epoch 1 NIRCam Imaging:Reduction Methods and Simulations Enabling Early JWST Science Results
We present the data release and data reduction process for the Epoch 1 NIRCam observations for the Cosmic Evolution Early Release Science Survey (CEERS). These data consist of NIRCam imaging in six broadband filters (F115W, F150W, F200W, F277W, F356W and F444W) and one medium-band filter (F410M) over four pointings, obtained in parallel with primary CEERS MIRI observations. We reduced the NIRCam imaging with the JWST Calibration Pipeline, with custom modifications and reduction steps designed to address additional features and challenges with the data. Here we provide a detailed description of each step in our reduction and a discussion of future expected improvements. Our reduction process includes corrections for known prelaunch issues such as 1/f noise, as well as in-flight issues including snowballs, wisps, and astrometric alignment. Many of our custom reduction processes were first developed with prelaunch simulated NIRCam imaging over the full 10 CEERS NIRCam pointings. We present a description of the creation and reduction of this simulated data set in the Appendix. We provide mosaics of the real images in a public release, as well as our reduction scripts with detailed explanations to allow users to reproduce our final data products. These represent one of the first official public data sets released from the Directors Discretionary Early Release Science (DD-ERS) program.</p
CEERS Epoch 1 NIRCam Imaging: Reduction Methods and Simulations Enabling Early JWST Science Results
We present the data release and data reduction process for the Epoch 1 NIRCam
observations for the Cosmic Evolution Early Release Science Survey (CEERS).
These data consist of NIRCam imaging in six broadband filters (F115W, F150W,
F200W, F277W, F356W and F444W) and one medium band filter (F410M) over four
pointings, obtained in parallel with primary CEERS MIRI observations (Yang et
al. in prep). We reduced the NIRCam imaging with the JWST Calibration Pipeline,
with custom modifications and reduction steps designed to address additional
features and challenges with the data. Here we provide a detailed description
of each step in our reduction and a discussion of future expected improvements.
Our reduction process includes corrections for known pre-launch issues such as
1/f noise, as well as in-flight issues including snowballs, wisps, and
astrometric alignment. Many of our custom reduction processes were first
developed with pre-launch simulated NIRCam imaging over the full 10 CEERS
NIRCam pointings. We present a description of the creation and reduction of
this simulated dataset in the Appendix. We provide mosaics of the real images
in a public release, as well as our reduction scripts with detailed
explanations to allow users to reproduce our final data products. These
represent one of the first official public datasets released from the Directors
Discretionary Early Release Science (DD-ERS) program.Comment: 27 pages, 14 figures, submitted to ApJ. Accompanying CEERS public
Data Release 0.5 available at ceers.github.io/releases.htm
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