The prevalence of hypertension increases with aging and is associated with increased arterial stiffness. Resistant hypertension is presented when drug treatments fail to regulate a sustained ...increased blood pressure. Given that the mechanisms between the sympathetic nervous system and the kidney play an important role in blood regulation, renal denervation (RDN) has emerged as a therapeutic potential in resistant hypertension. In this study, we investigated the effects of RDN on the biomechanical response and microstructure of elastic arteries. Common carotid arteries (CCA) excised from 3-month, 8-month, and 8-month denervated rats were subjected to biaxial extension-inflation test. Our results showed that hypertension developed in the 8-month-old rats. The sustained elevated blood pressure resulted in arterial remodeling which was manifested as a significant stress increase in both axial and circumferential directions after 8 months. RDN had a favorable impact on CCAs with a restoration of stresses in values similar to control arteries at 3 months. After biomechanical testing, arteries were imaged under a multi-photon microscope to identify microstructural changes in extracellular matrix (ECM). Quantification of multi-photon images showed no significant alterations of the main ECM components, elastic and collagen fibers, indicating that arteries remained intact after RDN. Regardless of the experimental group, our microstructural analysis of the multi-photon images revealed that reorientation of the collagen fibers might be the main microstructural mechanism taking place during pressurization with their straightening happening during axial stretching.
Eusocial insects use cuticular hydrocarbons as components of pheromones that mediate social behaviours, such as caste and nestmate recognition, and regulation of reproduction. In ants such as ...Harpegnathos saltator, the queen produces a pheromone which suppresses the development of workers' ovaries and if she is removed, workers can transition to a reproductive state known as gamergate. Here we functionally characterize a subfamily of odorant receptors (Ors) with a nine-exon gene structure that have undergone a massive expansion in ants and other eusocial insects. We deorphanize 22 representative members and find they can detect cuticular hydrocarbons from different ant castes, with one (HsOr263) that responds strongly to gamergate extract and a candidate queen pheromone component. After systematic testing with a diverse panel of hydrocarbons, we find that most Harpegnathos saltator Ors are narrowly tuned, suggesting that several receptors must contribute to detection and discrimination of different cuticular hydrocarbons important in mediating eusocial behaviour.Cuticular hydrocarbons (CHC) mediate the interactions between individuals in eusocial insects, but the sensory receptors for CHCs are unclear. Here the authors show that in ants such as H. saltator, the 9-exon subfamily of odorant receptors (HsOrs) responds to CHCs, and ectopic expression of HsOrs in Drosophila neurons imparts responsiveness to CHCs.
Leigh syndrome, an inherited neurometabolic disorder, is estimated to be the most common pediatric manifestation of mitochondrial disease. No treatments are currently available for Leigh syndrome due ...to many hurdles in drug discovery efforts. Leigh syndrome causal variants span over 110 different genes and likely lead to both unique and shared biochemical alterations, often resulting in overlapping phenotypic features. The mechanisms by which pathogenic variants in mitochondrial genes alter cellular phenotype to promote disease remain poorly understood. The rarity of cases of specific causal variants creates barriers to drug discovery and adequately sized clinical trials. BODY: To address the current challenges in drug discovery and facilitate communication between researchers, healthcare providers, patients, and families, the Boston University integrative Cardiovascular Metabolism and Pathophysiology (iCAMP) Lab and Cure Mito Foundation hosted a Leigh Syndrome Symposium. This symposium brought together expert scientists and providers to highlight the current successes in drug discovery and novel models of mitochondrial disease, and to connect patients to providers and scientists to foster community and communication.
In this symposium review, we describe the research presented, the hurdles ahead, and strategies to better connect the Leigh syndrome community members to advance treatments for Leigh syndrome.
Lesbian, gay, bisexual, transgender, and queer plus (LGBTQ+) students in undergraduate science, technology, engineering, and math (STEM) majors are more likely to drop out than their cisgender, ...heterosexual peers despite having equivalent grades and research exposure. It has been demonstrated that a sense of belonging, a very strong predictor of student retention, is low in LGBTQ+-identified STEM undergraduates. It has further been posited that faculty openness and authenticity can enhance a sense of belonging for LGBTQ+ students through the creation of an inclusive classroom culture. The authors of this article, three LGBTQ+-identified faculty in the health sciences department at Boston University, surveyed students enrolled in their courses to elicit student thoughts, feelings, and behaviors regarding the effect of faculty
) sharing their identity openly in the classroom, and
) actively working to create open, inclusive dialogue and space in their classrooms. Of 86 student participants across multiple classes, the large majority of students, both LGBTQ+-identified and non-LGBTQ+-identified, described feeling safe, included, and welcomed in the classroom. They described engaging more in peer-to-peer education and felt that instructor authenticity created a safe and inclusive classroom. A minority of LGBTQ+-identified students and non-LGBTQ+-identified students reported feeling unsure of voicing their opinions, for the former related to insecurity about being LGBTQ+ and the latter feeling a liberal bias existed in the classroom. Altogether, these results suggest a positive effect on student sense of belonging when faculty authenticity and intentionality create inclusive classroom environments in the health sciences.
Openness and authenticity of lesbian, gay, bisexual, transgender, and queer plus (LGBTQ+)-identified faculty in the health sciences positively affect students by helping them feel seen, welcomed, and included for both students who identify as LGBTQ+ and those who do not. Moreover, faculty openness fostered student action by encouraging them to have peer-to-peer discussions about inclusive language and engage more openly in classroom discussions. Creating academic job security for LGBTQ+-identified faculty to be open can enhance classroom culture, student engagement, and learning.
Background
Cancer cachexia is a metabolic wasting syndrome that is strongly associated with a poor prognosis. The initiating factors causing fat and muscle loss are largely unknown. Previously, we ...found that leukaemia inhibitory factor (LIF) secreted by C26 colon carcinoma cells was responsible for atrophy in treated myotubes. In the present study, we tested whether C26 tumour‐derived LIF is required for cancer cachexia in mice by knockout of Lif in C26 cells.
Methods
A C26 Lif null tumour cell line was made using CRISPR‐Cas9. Measurements of cachexia were compared in mice inoculated with C26 vs. C26Lif−/− tumour cells, and atrophy was compared in myotubes treated with medium from C26 vs. C26Lif−/− tumour cells. Levels of 25 cytokines/chemokines were compared in serum of mice bearing C26 vs. C26Lif−/− tumours and in the medium from these tumour cell lines.
Results
At study endpoint, C26 mice showed outward signs of sickness while mice with C26Lif−/− tumours appeared healthy. Mice with C26Lif−/− tumours showed a 55–75% amelioration of body weight loss, muscle loss, fat loss, and splenomegaly compared with mice with C26 tumours (P < 0.05). The heart was not affected by LIF levels because the loss of cardiac mass was the same in C26 and C26Lif−/− tumour‐bearing mice. LIF levels in mouse serum was entirely dependent on secretion from the tumour cells. Serum levels of interleukin‐6 and G‐CSF were increased by 79‐fold and 68‐fold, respectively, in C26 mice but only by five‐fold and two‐fold, respectively, in C26Lif−/− mice, suggesting that interleukin‐6 and G‐CSF increases are dependent on tumour‐derived LIF.
Conclusions
This study shows the first use of CRISPR‐Cas9 knockout of a candidate cachexia factor in tumour cells. The results provide direct evidence for LIF as a major cachexia initiating factor for the C26 tumour in vivo. Tumour‐derived LIF was also a regulator of multiple cytokines in C26 tumour cells and in C26 tumour‐bearing mice. The identification of tumour‐derived factors such as LIF that initiate the cachectic process is immediately applicable to the development of therapeutics to treat cachexia. This is a proof of principle for studies that when carried out in human cells, will make possible an understanding of the factors causing cachexia in a patient‐specific manner.
Hypertension, a major public health issue, is estimated to contribute to 10% of all deaths worldwide. Further, the salt sensitivity of blood pressure is a critical risk factor for the development of ...hypertension. The hypothalamic paraventricular nucleus (PVN) coordinates neuro-hormonal responses to alterations in plasma sodium and osmolality and multiple G Protein-Coupled Receptors (GPCRs) are involved in fluid and electrolyte homeostasis. In acute animal studies, our laboratory has shown that central Gαi/o subunit protein signal transduction mediates hypotensive and bradycardic responses and that Gz/q, proteins mediate the release of arginine vasopressin (AVP) and subsequent aquaretic responses to acute pharmacological stimuli. Extending these studies, our laboratory has shown that central Gαi
2
proteins selectively mediate the hypotensive, sympathoinhibitory and natriuretic responses to acute pharmacological activation of GPCRs and in response to acute physiological challenges to fluid and electrolyte balance. In addition, following chronically elevated dietary sodium intake, salt resistant rats demonstrate site-specific and subunit-specific upregulation of Gαi
2
proteins in the PVN, resulting in sympathoinhibition and normotension. In contrast, chronic dietary sodium intake in salt sensitive animals, which fail to upregulate PVN Gαi
2
proteins, results in the absence of dietary sodium-evoked sympathoinhibition and salt sensitive hypertension. Using
in situ
hybridization, we observed that Gαi
2
expressing neurons in parvocellular division of the PVN strongly (85%) colocalize with GABAergic neurons. Our data suggest that central Gαi
2
protein-dependent responses to an acute isotonic volume expansion (VE) and elevated dietary sodium intake are mediated by the peripheral sensory afferent renal nerves and do not depend on the anteroventral third ventricle (AV3V) sodium sensitive region or the actions of central angiotensin II type 1 receptors. Our translational human genomic studies have identified three G protein subunit alpha I2 (GNAI2) single nucleotide polymorphisms (SNPs) as potential biomarkers in individuals with salt sensitivity and essential hypertension. Collectively, PVN Gαi
2
proteins-gated pathways appear to be highly conserved in salt resistance to counter the effects of acute and chronic challenges to fluid and electrolyte homeostasis on blood pressure
via
a renal sympathetic nerve-dependent mechanism.
A clear, inclusive, and accurate approach to the collection of demographic information in clinical research and medical practice is critical to understanding the healthcare needs of the specific ...population. Inclusive demography constitutes appropriate and accurate characterization of an individual's sexual orientation and gender identity (SOGI) data. Appropriate demography fosters sense of inclusion and belonging for those belonging to medically marginalized communities such as the lesbian, gay, bisexual, transgender, queer, intersex, asexual, and Indigenous Two-Spirit (LGBTQIA2S+) communities and improves health outcomes. Acquiring inclusive demographics in healthcare research is needed for the following critical reasons. First, LGBTQIA2S+ individuals experience undue psychological harm when their identities are not appropriately captured in survey data, promoting further alienation of the LGBTQIA2S+ community in medicine and research. Second, LGBTQIA2S+ populations are disproportionately burdened by several major cardiovascular and cardiovascular-associated diseases, including hypertension and diabetes. Failure to include these populations, and accurately characterize their participation, in research leads to failure to identify associations between identities and disease, resulting in worse health outcomes. Furthermore, this lack of precision in current data for sex, gender, and sexual orientation may lead to inaccurate data for all populations, not just the LGBTQIA2S+ community. Finally, there are currently major political and social threats and attacks on the LGBTQIA2S+ community and, in particular, on transgender and gender-diverse individuals. Proper medical inclusion and advocacy for the LGBTQIA2S+ community by the medical community may help protect the community from further undue harm through creating sense of belonging and reductions in marginalization-related health inequities.
Nuclear-mitochondrial DNA segments (NUMTs) are mitochondrial DNA (mtDNA) fragments that have been inserted into the nuclear genome. Some NUMTs are common within the human population but most NUMTs ...are rare and specific to individuals. NUMTs range in size from 24 base pairs to encompassing nearly the entire mtDNA and are found throughout the nuclear genome. Emerging evidence suggests that the formation of NUMTs is an ongoing process in humans. NUMTs contaminate sequencing results of the mtDNA by introducing false positive variants, particularly heteroplasmic variants present at a low variant allele frequency (VAF). In our review, we discuss the prevalence of NUMTs in the human population, the potential mechanisms of de novo NUMT insertion via DNA repair mechanisms, and provide an overview of the existing approaches for minimizing NUMT contamination. Apart from filtering known NUMTs, both wet lab-based and computational methods can be used to minimize the contamination of NUMTs in analyses of human mtDNA. Current approaches include: (1) isolating mitochondria to enrich for mtDNA; (2) applying basic local alignment to identify NUMTs for subsequent filtering; (3) bioinformatic pipelines for NUMT detection; (4) k-mer-based NUMT detection; and (5) filtering candidate false positive variants by mtDNA copy number, VAF, or sequence quality score. Multiple approaches must be applied in order to effectively identify NUMTs in samples. Although next-generation sequencing is revolutionizing our understanding of heteroplasmic mtDNA, it also raises new challenges with the high prevalence and individual-specific NUMTs that need to be handled with care in studies of mitochondrial genetics.
Mitochondrial DNA (mtDNA) variants cause a range of diseases from severe pediatric syndromes to aging-related conditions. The percentage of mtDNA copies carrying a pathogenic variant, variant allele ...frequency (VAF), must reach a threshold before a biochemical defect occurs, termed the biochemical threshold. Whether the often-cited biochemical threshold of >60% VAF is similar across mtDNA variants and cell types is unclear. In our systematic review, we sought to identify the biochemical threshold of mtDNA variants in relation to VAF by human tissue/cell type. We used controlled vocabulary terms to identify articles measuring oxidative phosphorylation (OXPHOS) complex activities in relation to VAF. We identified 76 eligible publications, describing 69, 12, 16, and 49 cases for complexes I, III, IV, and V, respectively. Few studies evaluated OXPHOS activities in diverse tissue types, likely reflective of clinical access. A number of cases with similar VAFs for the same pathogenic variant had varying degrees of residual activity of the affected complex, alluding to the presence of modifying variants. Tissues and cells with VAFs <60% associated with low complex activities were described, suggesting the possibility of a biochemical threshold of <60%. Using Kendall rank correlation tests, the VAF of the m.8993T > G variant correlated with complex V activity in skeletal muscle (τ = -0.58,
= 0.01, n = 13); however, no correlation was observed in fibroblasts (
= 0.7, n = 9). Our systematic review highlights the need to investigate the biochemical threshold over a wider range of VAFs in disease-relevant cell types to better define the biochemical threshold for specific mtDNA variants.
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