Dominant-negative mutations potentiated by the HSF1-regulated proteostasis network.

Protein mutational landscapes are sculpted by the impacts of the resulting amino acid substitutions on the protein's stability and folding or aggregation kinetics. These properties can, in turn, be modulated by the composition and activities of the cellular proteostasis network. Heat shock factor 1 (HSF1) is the master regulator of the cytosolic and nuclear proteostasis networks, dynamically tuning the expression of cytosolic and nuclear chaperones and quality control factors to meet demand.

An HSF1-JMJD6-HSP feedback circuit promotes cell adaptation to proteotoxic stress.

Heat Shock Factor 1 (HSF1) is best known as the master transcriptional regulator of the heat-shock response (HSR), a conserved adaptive mechanism critical for protein homeostasis (proteostasis). Combining a genome-wide RNAi library with an HSR reporter, we identified Jumonji domain-containing protein 6 (JMJD6) as an essential mediator of HSF1 activity. In follow-up studies, we found that JMJD6 is itself a noncanonical transcriptional target of HSF1 which acts as a critical regulator of proteostasis.

Tight regulation of a nuclear HAPSTR1-HUWE1 pathway essential for mammalian life.

The recently discovered HAPSTR1 protein broadly oversees cellular stress responses. This function requires HUWE1, a ubiquitin ligase that paradoxically marks HAPSTR1 for degradation, but much about this pathway remains unclear. Here, leveraging multiplexed proteomics, we find that HAPSTR1 enables nuclear localization of HUWE1 with implications for nuclear protein quality control.

The HAPSTR2 retrogene buffers stress signaling and resilience in mammals.

We recently identified HAPSTR1 (C16orf72) as a key component in a novel pathway which regulates the cellular response to molecular stressors, such as DNA damage, nutrient scarcity, and protein misfolding. Here, we identify a functional paralog to HAPSTR1: HAPSTR2. HAPSTR2 formed early in mammalian evolution, via genomic integration of a reverse transcribed HAPSTR1 transcript, and has since been preserved under purifying selection.

C16orf72/HAPSTR1 is a molecular rheostat in an integrated network of stress response pathways.

All cells contain specialized signaling pathways that enable adaptation to specific molecular stressors. Yet, whether these pathways are centrally regulated in complex physiological stress states remains unclear. Using genome-scale fitness screening data, we quantified the stress phenotype of 739 cancer cell lines, each representing a unique combination of intrinsic tumor stresses.

The mTORC1-SLC4A7 axis stimulates bicarbonate import to enhance de novo nucleotide synthesis.

Bicarbonate (HCO) ions maintain pH homeostasis in eukaryotic cells and serve as a carbonyl donor to support cellular metabolism. However, whether the abundance of HCO is regulated or harnessed to promote cell growth is unknown. The mechanistic target of rapamycin complex 1 (mTORC1) adjusts cellular metabolism to support biomass production and cell growth.

HSF2 cooperates with HSF1 to drive a transcriptional program critical for the malignant state.

Heat shock factor 1 (HSF1) is well known for its role in the heat shock response (HSR), where it drives a transcriptional program comprising heat shock protein (HSP) genes, and in tumorigenesis, where it drives a program comprising HSPs and many noncanonical target genes that support malignancy. Here, we find that HSF2, an HSF1 paralog with no substantial role in the HSR, physically and functionally interacts with HSF1 across diverse types of cancer. HSF1 and HSF2 have notably similar chromatin occupancy and regulate a common set of genes that include both HSPs and noncanonical transcriptional targets with roles critical in supporting malignancy.

A network of core and subtype-specific gene expression programs in myositis.

Myositis comprises a heterogeneous group of skeletal muscle disorders which converge on chronic muscle inflammation and weakness. Our understanding of myositis pathogenesis is limited, and many myositis patients lack effective therapies. Using muscle biopsy transcriptome profiles from 119 myositis patients (spanning major clinical and serological disease subtypes) and 20 normal controls, we generated a co-expression network of 8101 dynamically regulated transcripts.

FIREWORKS: a bottom-up approach to integrative coessentiality network analysis.

Genetic coessentiality analysis, a computational approach which identifies genes sharing a common effect on cell fitness across large-scale screening datasets, has emerged as a powerful tool to identify functional relationships between human genes. However, widespread implementation of coessentiality to study individual genes and pathways is limited by systematic biases in existing coessentiality approaches and accessibility barriers for investigators without computational expertise. We created FIREWORKS, a method and interactive tool for the construction and statistical analysis of coessentiality networks centered around gene(s) provided by the user.

Quantitative and multiplexed chemical-genetic phenotyping in mammalian cells with QMAP-Seq.

Chemical-genetic interaction profiling in model organisms has proven powerful in providing insights into compound mechanism of action and gene function. However, identifying chemical-genetic interactions in mammalian systems has been limited to low-throughput or computational methods. Here, we develop Quantitative and Multiplexed Analysis of Phenotype by Sequencing (QMAP-Seq), which leverages next-generation sequencing for pooled high-throughput chemical-genetic profiling.

Posttranslational Regulation of the Exon Skipping Machinery Controls Aberrant Splicing in Leukemia.

Splicing alterations are common in diseases such as cancer, where mutations in splicing factor genes are frequently responsible for aberrant splicing. Here we present an alternative mechanism for splicing regulation in T-cell acute lymphoblastic leukemia (T-ALL) that involves posttranslational stabilization of the splicing machinery via deubiquitination. We demonstrate there are extensive exon skipping changes in disease, affecting proteasomal subunits, cell-cycle regulators, and the RNA machinery.

Impact of Telemonitoring of Critically Ill Emergency Department Patients Awaiting ICU Transfer.

Objectives: Because of overcrowding and limited critical care resources, critically ill patients in the emergency department may spend hours to days awaiting transfer to the ICU. In these patients, often termed "ICU boarders," delayed ICU transfer is associated with poor outcomes. We implemented an emergency department-based, electronic ICU monitoring system for ICU boarders.

Myositis Autoantigen Expression Correlates With Muscle Regeneration but Not Autoantibody Specificity.

Objective: Although more than a dozen myositis-specific autoantibodies (MSAs) have been identified, most patients with myositis are positive for a single MSA. The specific overexpression of a given myositis autoantigen in myositis muscle has been proposed as initiating and/or propagating autoimmunity against that particular autoantigen. The present study was undertaken to test this hypothesis.

Muscle endurance deficits in myositis patients despite normal manual muscle testing scores.

Introduction: It is unclear whether quantitating muscle endurance adds nonredundant information useful for the care of patients with muscular disease.

Methods: Records were retrospectively reviewed for all Johns Hopkins Myositis Center patients with a muscle endurance assessment (n = 128, 226 patient-visits). Muscle endurance and strength were quantitated with the Myositis Functional Index-2 (FI2) and manual muscle testing (MMT), respectively.

Calcium dysregulation, functional calpainopathy, and endoplasmic reticulum stress in sporadic inclusion body myositis.

Sporadic inclusion body myositis (IBM) is the most common primary myopathy in the elderly, but its pathoetiology is still unclear. Perturbed myocellular calcium (Ca) homeostasis can exacerbate many of the factors proposed to mediate muscle degeneration in IBM, such as mitochondrial dysfunction, protein aggregation, and endoplasmic reticulum stress. Ca dysregulation may plausibly be initiated in IBM by immune-mediated membrane damage and/or abnormally accumulating proteins, but no studies to date have investigated Ca regulation in IBM patients.

Aging reversibility: from thymus graft to vegetable extract treatment-- application to cure an age-associated pathology.

Neonatal thymus graft and thymus calf extract (TME) in vivo treatment exert similar corrective actions on different mouse age-related alterations. The aim of the present paper is to investigate whether a vegetal extract, wheat sprout extract (WESPRE), could mimic the thymus action on recovering age-related alterations and if this extract can cure an age-associated pathology, the cataract in dogs. Present experiments were carried out by using WESPRE and TME in vivo in old mice to check their ability to recover the altered DNA synthesis in hepatocyte primary cultures.

Purified angiotensin converting enzyme from Rana esculenta ovary influences ovarian steroidogenesis in vitro.

The aim of the present study was to purify and characterize angiotensin-converting enzyme (ACE) present in frog ovary (Rana esculenta). Detergent and trypsin-extracted enzymes were purified using a one-step process, consisting of affinity chromatography on lisinopril coupled to Sepharose 6B. The molecular mass was 150 kDa for both detergent-extracted and trypsin-extracted enzyme.

Seasonal changes in angiotensin converting enzyme activity in male and female frogs (Rana esculenta).

Gonad, lung, kidney and serum angiotensin converting enzyme (ACE) activities were determined by specific substrate hydrolysis in male and female Rana esculenta over 1 year. Ovary ACE activity showed the highest values among the different tissues, with a significant peak (223+/-52 nmol min(-1) mg protein(-1)) in late winter-early spring. Testis ACE activity followed a significant seasonal cycle, increasing from September to peak in April (2.

Degradation of thymic humoral factor gamma2 by human plasma: involvement of angiotensin converting enzyme.

The degradation of thymic humoral factor-gamma2 (THF-gamma2), an immunoregulatory octapeptide important for T-lymphocyte regulation, by enzymes present in human plasma, was investigated. THF-gamma2 was metabolized through two steps that involved the detaching of N-terminal amino acid leucine followed by hydrolysis of the Lys(6)-Phe(7) bond. The THF-gamma2 cleavages were sensitive to aminopeptidase and metalloproteinase inhibitors.

Noninvasive cardiac output assessment during heart surgery.

Objective: To evaluate the reliability of a new noninvasive method for the assessment of cardiac output with the partial carbon dioxide rebreathing technique.

Methods: This technique was applied to patients undergoing heart surgery. Values of cardiac index obtained with this equipment were compared with the artero-venous CO2 gradient, a reliable index of cardiovascular status.

Bradykinin is not involved in angiotensin converting enzyme modulation of ovarian steroidogenesis and prostaglandin production in frog Rana esculenta.

Angiotensin converting enzyme (ACE) was demonstrated to modulate the production of 17beta-estradiol, progesterone and prostaglandin E2 (PGE2) in frog ovary of Rana esculenta. However, the activity was not mediated by angiotensin II (Ang II). In an attempt to identify the peptide involved in the pathway modulated by ACE, bradykinin, another physiological substrate of ACE, was chosen and incubated in the presence of the membrane suspension purified from the frog ovary homogenate.

Effect of general and epidural anaesthesia on thyroid hormones and immunity in neonates.

Background: The aim of this study was to verify if variations of thyroid hormones related to circumstances of delivery and mode of maternal anaesthesia can contribute to neonatal neutrophil respiratory burst and natural killer cell activity.

Methods: We evaluated 10 infants born by vaginal delivery (group A), 10 infants born by caesarean section after epidural anaesthesia with lidocaine (group B) and 10 infants born by caesarean section after general anaesthesia with sevoflurane (group C).

Results: A significant reduction of neutrophil respiratory burst test was found in groups A and C compared with group B.

Does ethnicity predict lactation? A study of four ethnic communities.

Human lactation is influenced by a variety of interrelated factors. The purpose of the study was to see whether the racial/ethnic factor is predictive of the onset of lactation and of the volume of breast milk. We planned a prospective study enrolling 269 women who were classified into four ethnic groups: Group 1 Arabs, Group 2 Africans, Group 3 Eastern Europeans, Group 4 Italians.

Synthesis and characterization of tetramethylrhodaminethiocarbamoyl-(Glu(1))-epidermal mitosis-inhibiting pentapeptide.

A fluorescent analog of epidermal mitosis-inhibiting pentapeptide (pGlu-Glu-Asp-Ser-Gly) was synthesized by reacting tetramethylrhodamine isothiocyanate with ring-opened epidermal mitosis-inhibiting pentapeptide. The ring-opening reaction of the pyrrolidone moiety was performed with mild acidic hydrolysis and the product purified by reversed-phase high-performance liquid chromatography. Tetramethylrhodaminethiocarbamoyl-(Glu(1))-epidermal mitosis-inhibiting pentapeptide was purified by chromatography on Sephadex G-25 and reversed-phase high-performance liquid chromatography.