Faculty Bibliography
Searched for:
school:SOM
Department/Unit:Cell Biology
Total Results:
14040
Oocytes with impaired meiotic maturation contain increased mtDNA deletions
PURPOSE/OBJECTIVE:Induction of meiotic competence is a major goal of the controlled ovarian stimulation used in ART. Do factors intrinsic to the oocyte contribute to oocyte maturation? Deletions in mtDNA accumulate in long-lived post mitotic tissues and are found in human oocytes. If oogenesis cleanses the germline of deleterious deletions in mtDNA, meiotically competent oocytes should contain lower levels of mtDNA deletions vs. meiotically arrested oocytes. We tested this hypothesis using a novel PCR assay for a deletion ratio in human oocytes derived from IVF. METHODS:among oocytes which matured to metaphase II (MII) vs. oocytes arrested at GV or metaphase I (MI). RESULTS:51.75% of oocytes reached MII, and 17% remained at MI. Mean mtDNADR in GV, MI and MII oocytes were 27.87%, 31.88% and 20.05%, respectively. The difference in deletion ratios between GV and MII and between MI and MII stages was statistically significant p < 0.001 and p = 0.034, respectively. Additionally, patient age was found to be positively correlated with time to Polar body extrusion (- 0.278 Pearson correlation). CONCLUSIONS:Oocytes with impaired meiotic maturation contain an increased load of mtDNA deletions. This is the first report of an association between the mtDNA deletion ratio and human oocyte maturation in vitro.
PMID: 39863755
ISSN: 1573-7330
CID: 5802772
Phospholipid Transport Across the Bacterial Periplasm Through the Envelope-spanning Bridge YhdP
The outer membrane of Gram-negative bacteria provides a formidable barrier, essential for both pathogenesis and antimicrobial resistance. Biogenesis of this complex structure necessitates the transport of phospholipids across the cell envelope. Recently, YhdP was implicated as a major protagonist in the trafficking of inner membrane phospholipids to the outer membrane; however the molecular mechanism of YhdP mediated transport remains elusive. Here, utilising AlphaFold, we observe YhdP to form an elongated assembly of 60 β-strands that curve to form a continuous hydrophobic groove. This architecture is consistent with our negative stain electron microscopy data which reveals YhdP to be approximately 250 Å in length and thus sufficient to span the bacterial cell envelope. Furthermore, molecular dynamics simulations and bacterial growth assays indicate essential helical regions at the N- and C-termini of YhdP, that may embed into the inner and outer membranes respectively, reinforcing its envelope spanning nature. Our in vivo crosslinking data reveal phosphate-containing substrates captured along the length of the YhdP groove, providing direct evidence that YhdP interacts with a phosphate-containing substrate, which we propose to be phospholipids. This finding is congruent with our molecular dynamics simulations which demonstrate the propensity for inner membrane lipids to spontaneously enter the groove of YhdP. Collectively, our results support a model in which YhdP bridges the cell envelope, providing a hydrophobic environment for the transport of phospholipids to the outer membrane.
PMID: 39638236
ISSN: 1089-8638
CID: 5804572
Meeting report - Alpine desmosome disease meeting 2024: advances and emerging topics in desmosomes and related diseases
Desmosomes are adhesive cell contacts abundant in tissues exposed to mechanical strain, such as the stratified and simple epithelia of the epidermis and mucous membranes, as well as the myocardium. Besides their role in mechanical cell cohesion, desmosomes also modulate pathways important for tissue differentiation, wound healing and immune responses. Dysfunctional desmosomes, resulting from pathogenic variants in genes encoding desmosomal components, autoantibodies targeting desmosomal adhesion molecules or inflammation, cause the life-threatening diseases arrhythmogenic cardiomyopathy and pemphigus and contribute to the pathogenesis of inflammatory bowel diseases. The Alpine Desmosome Disease Meeting 2024 (ADDM 2024), held in Grainau, Germany in October 2024, connected international researchers from basic sciences with clinical experts from dermatology, cardiology, gastroenterology and surgery. The participants discussed recent advances, identified hot topics in desmosome biology and disease and provided new concepts for pathogenesis and treatment approaches.
PMID: 39838950
ISSN: 1477-9137
CID: 5778512
The impact of neoadjuvant therapy in patients with left-sided resectable pancreatic cancer: an international multicenter study
PURPOSE/OBJECTIVE:To assess the association between neoadjuvant therapy and overall survival (OS) in patients with left-sided resectable pancreatic cancer (RPC) compared to upfront surgery. BACKGROUND:Left-sided pancreatic cancer is associated with worse OS compared to right-sided pancreatic cancer. Although neoadjuvant therapy is currently seen as not effective in patients with RPC, current randomized trials included mostly patients with right-sided RPC. METHODS:International multicenter retrospective study including consecutive patients after left-sided pancreatic resection for pathology-proven RPC, either after neoadjuvant therapy or upfront surgery in 76 centers from 18 countries on 4 continents (2013-2019). Primary endpoint is OS from diagnosis. Time-dependent Cox regression analysis was performed to investigate the association of neoadjuvant therapy with OS, adjusting for confounders at time of diagnosis. Adjusted OS probabilities were calculated. RESULTS:=0.96) involvement. CONCLUSIONS:Neoadjuvant therapy in patients with left-sided RPC was associated with improved OS compared to upfront surgery. The impact of neoadjuvant therapy increased with larger tumor size and higher serum CA19-9 at diagnosis. Randomized controlled trials on neoadjuvant therapy specifically in patients with left-sided RPC are needed.
PMID: 39814200
ISSN: 1569-8041
CID: 5776932
Exploring the Rise in Pediatric "Skincare Routines" on Social Media [Letter]
PMID: 39803709
ISSN: 1365-4632
CID: 5776242
An integrated approach for the accurate detection of HERV-K HML-2 transcription and protein synthesis
Human endogenous retroviruses (HERVs) occupy a large portion of the human genome. Most HERVs are transcriptionally silent, but they can be reactivated during pathological states such as viral infection and certain cancers. The HERV-K HML-2 clade includes elements that recently integrated have in the human germ line and often contain intact open reading frames that possibly support peptide and protein expression. Understanding HERV-K-host interactions and their potential as biomarkers is problematic due to the high similarity among different elements. Previously, we described a long-read single molecule real-time sequencing (PacBio) strategy to analyze HERV-K RNA expression profiles in different cell types. However, identifying HERV-K HML-2 proteins accurately is difficult without robust and reliable methods and reagents. Here we present a new approach to characterize the HML-2 elements that (a) are being translated and (b) produce enough protein to be detected and identified by mass spectrometry. Our data reveal that RNA expression profiling alone cannot accurately predict which HML-2 elements are responsible for protein production, as we observe several differences between the highest expressed RNAs and the elements that are the predominant source of HERV-K HML-2 protein synthesis. These studies represent an important advance toward untangling the complexity of HERV-K-host interactions.
PMCID:11744191
PMID: 39831303
ISSN: 1362-4962
CID: 5778442
A fiducial-assisted strategy compatible with resolving small MFS transporter structures in multiple conformations using cryo-EM
Advancements in cryo-EM have stimulated a revolution in structural biology. Yet, for membrane proteins near the cryo-EM size threshold of approximately 40 kDa, including transporters and G-protein coupled receptors, the absence of distinguishable structural features makes image alignment and structure determination a significant challenge. Furthermore, resolving more than one protein conformation within a sample, a major advantage of cryo-EM, represents an even greater degree of difficulty. Here, we describe a strategy for introducing a rigid fiducial marker (BRIL domain) at the C-terminus of membrane transporters from the Major Facilitator Superfamily (MFS) with AlphaFold2. This approach involves fusion of the last transmembrane domain helix of the target protein with the first helix of BRIL through a short poly-alanine linker to promote helicity. Combining this strategy with a BRIL-specific Fab, we elucidated four cryo-EM structures of the 42 kDa Staphylococcus aureus transporter NorA, three of which were derived from a single sample corresponding to inward-open, inward-occluded, and occluded conformations. Hence, this fusion construct facilitated experiments to characterize the conformational landscape of NorA and validated our design to position the BRIL/antibody pair in an orientation that avoids steric clash with the transporter. The latter was enabled through AlphaFold2 predictions, which minimized guesswork and reduced the need for screening several constructs. We further validated the suitability of the method to three additional MFS transporters (GlpT, Bmr, and Blt), results that supported a rigid linker between the transporter and BRIL. The successful application to four MFS proteins, the largest family of secondary transporters in nature, and analysis of predicted structures for the family indicates this strategy will be a valuable tool for studying other MFS members using cryo-EM.
PMCID:11695964
PMID: 39746942
ISSN: 2041-1723
CID: 5779252
Evaluating the Severity Spectrum: A Hierarchical Analysis of Complications during Hip Fracture Admission Associated with Mortality
OBJECTIVES/OBJECTIVE:To determine which in-hospital complications following the operative treatment of hip fractures are associated with increased inpatient, 30-day and 1 year mortality. METHODS:Design: Retrospective study. SETTING/METHODS:A single academic medical center and a Level 1 Trauma Center. PATIENT SELECTION CRITERIA/UNASSIGNED:All patients who were operatively treated for hip fractures (OTA/AO 31A, 31B and Vancouver A,B, and C periprosthetic fractures) at a single center between October, 2014 and June, 2023. OUTCOME MEASURES AND COMPARISONS/UNASSIGNED:Occurrence of an in-hospital complication was recorded. Cohorts were based upon mortality time points (during admission, 30-days and 1-year) and compared to patients who were alive at those time points to determine which in- hospital complications were most associated with mortality. Correlation analysis was performed between patients who died and those who were alive at each time point. RESULTS:A total of 3,134 patients (average age of 79.6 years, range 18-104 years and 66.6% female) met inclusion for this study. The overall mortality rate during admission, 30 days and 1 year were found to be 1.6%, 3.9% and 11.1%, respectively. Sepsis was the complication most associated with increased in-hospital mortality (OR: 7.79, 95% CI 3.22 - 18.82, p<0.001) compared to other in-hospital complications. Compared to other in-hospital complications, stroke was the complication most associated with 30-day mortality (OR: 7.95, 95% CI 1.82 - 34.68, p<0.001). Myocardial infarction was the complication most associated with 1-year mortality (OR: 2.86, 95% CI 1.21 - 6.77, p=0.017) compared to other in-hospital complications. CONCLUSIONS:Post-operative sepsis, stroke and myocardial infraction were the three complications most associated with mortality during admission, 30-day mortality and 1-year mortality, respectively, during the operative treatment of hip fractures. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
PMID: 39207724
ISSN: 1531-2291
CID: 5729922
Tau is a receptor with low affinity for glucocorticoids and is required for glucocorticoid-induced bone loss
Glucocorticoids (GCs) are the most prescribed anti-inflammatory and immunosuppressive drugs. However, their use is often limited by substantial side effects, such as GC-induced osteoporosis (GIO) with the underlying mechanisms still not fully understood. In this study, we identify Tau as a low-affinity binding receptor for GCs that plays a crucial role in GIO. Tau deficiency largely abolished bone loss induced by high-dose dexamethasone, a synthetic GC, in both inflammatory arthritis and GIO models. Furthermore, TRx0237, a Tau inhibitor identified from an FDA-approved drug library, effectively prevented GIO. Notably, combinatorial administration of TRx0237 and dexamethasone completely overcame the osteoporosis adverse effect of dexamethasone in treating inflammatory arthritis. These findings present Tau as a previously unrecognized GC receptor with low affinity, and provide potential strategies to mitigate a spectrum of GC-related adverse effects, particularly osteoporosis.
PMCID:11701132
PMID: 39743632
ISSN: 1748-7838
CID: 5781852
MetFinder: A Tool for Automated Quantitation of Metastatic Burden in Histological Sections From Preclinical Models
As efforts to study the mechanisms of melanoma metastasis and novel therapeutic approaches multiply, researchers need accurate, high-throughput methods to evaluate the effects on tumor burden resulting from specific interventions. We show that automated quantification of tumor content from whole slide images is a compelling solution to assess in vivo experiments. In order to increase the outflow of data collection from preclinical studies, we assembled a large dataset with annotations and trained a deep neural network for the quantitative analysis of melanoma tumor content on histopathological sections of murine models. After assessing its performance in segmenting these images, the tool obtained consistent results with an orthogonal method (bioluminescence) of measuring metastasis in an experimental setting. This AI-based algorithm, made freely available to academic laboratories through a web-interface called MetFinder, promises to become an asset for melanoma researchers and pathologists interested in accurate, quantitative assessment of metastasis burden.
PMID: 39254030
ISSN: 1755-148x
CID: 5690152
