Faculty Bibliography

OBJECTIVE: It is well known that the embryo aneuploidy rate increases with women's age [1], but the effect of age on complex chromosomal abnormality (CCA) is less clear. Here, we addressed the relationship between maternal age and CCA with a retrospective cohort study. MATERIALS AND METHODS: We reviewed results of preimplantation genetic testing (PGT) by aCGH or NGS of embryo biopsies performed in an academic IVF unit between 2010 and 2019. We excluded PGT results from single gene disorder and egg donation cycles. CCA was defined as>=3 chromosome abnormalities (whole, partial and/or mosaic). Maternal age was categorized according to SART age groups: <35, 35-37, 38-40, 41-42, and >42 years. Statistical analyses were conducted using GraphPad Prism 8.
RESULT(S): 27,423 embryos were biopsied from 3,501 women aged 23 to 48 years. 4,740 embryos (16%) has CCA. Consistent with prior study [2], the most frequent chromosomes involved in CCA were 22, 16, 21 and 15, with incidences of 30.6%, 29.1%, 26.1% and 25.8% respectively. The number of chromosomal errors (from 3 to 42) involved in CCA did not correlate with maternal age (Spearman r = -0.0149, P = 0.3352). However, the rate of complex abnormal embryos tended to increase with advancing maternal age (9.7%, 11.2%, 10.9%, 24.8% and 43.6% in women aged < 35, 35-37, 38-40, 41-42, and > 42 years, respectively). Women over 40 years old had significantly higher rates of CCA compared to those under 40 years (Chisquare test, P < 0.0001). Surprisingly, the relationship between maternal age and CCA followed a U-shaped curve, decreasing from the 25 to 30 year old group (Pearson r = -0.831, P = 0.04) to the 30 to 35 year old group (Pearson r = 0.093, P = 0.861), then increased markedly in the 35 to 48 year old group (Pearson r = 0.921, P < 0.0001).
CONCLUSION(S):We found that CCA embryos share common features of aneuploidy, such as association with maternal age and preferential involvement of shorter chromosomes i.e. 22, 16, 21 and 15. Unexpectedly, our data showed that the relationship between CCA and maternal age assumes a U shape with increased rates at very young and very old ages. Both meiotic and mitotic errors contribute to chromosomal abnormality, and the contribution of each to CCA merits further investigation. IMPACT STATEMENT: The complex relationship between maternal age and embryo aneuploidy, which approximates a U-shape, may inform optimal timing of elective oocyte freezing and oocyte donation

TNFR1 and TNFR2 have received prominent attention because of their dominance in the pathogenesis of inflammation and autoimmunity. TNFR1 has been extensively studied and primarily mediates inflammation. TNFR2 remains far less studied, although emerging evidences demonstrate that TNFR2 plays an anti-inflammatory and immunoregulatory role in various conditions and diseases. Herein, we report that TNFR2 regulates macrophage polarization, a highly dynamic process controlled by largely unidentified intracellular regulators. Using biochemical co-purification and mass spectrometry approaches, we isolated the signaling molecule 14-3-3ε as a component of TNFR2 complexes in response to progranulin stimulation in macrophages. In addition, 14-3-3ε was essential for TNFR2 signaling-mediated regulation of macrophage polarization and switch. Both global and myeloid-specific deletion of 14-3-3ε resulted in exacerbated inflammatory arthritis and counteracted the protective effects of progranulin-mediated TNFR2 activation against inflammation and autoimmunity. TNFR2/14-3-3ε signaled through PI3K/Akt/mTOR to restrict NF-κB activation while simultaneously stimulating C/EBPβ activation, thereby instructing macrophage plasticity. Collectively, this study identifies 14-3-3ε as a previously-unrecognized vital component of the TNFR2 receptor complex and provides new insights into the TNFR2 signaling, particularly its role in macrophage polarization with therapeutic implications for various inflammatory and autoimmune diseases with activation of the TNFR2/14-3-3ε anti-inflammatory pathway.

α-ketoglutarate (KG), also referred to as 2-oxoglutarate, is a key intermediate of cellular metabolism with pleiotropic functions. Cell-permeable esterified analogs are widely used to study how KG fuels bioenergetic and amino acid metabolism and DNA, RNA, and protein hydroxylation reactions, as cellular membranes are thought to be impermeable to KG. Here we show that esterified KG analogs rapidly hydrolyze in aqueous media, yielding KG that, in contrast to prevailing assumptions, imports into many cell lines. Esterified KG analogs exhibit spurious KG-independent effects on cellular metabolism, including extracellular acidification, arising from rapid hydrolysis and de-protonation of α-ketoesters, and significant analog-specific inhibitory effects on glycolysis or mitochondrial respiration. We observe that imported KG decarboxylates to succinate in the cytosol and contributes minimally to mitochondrial metabolism in many cell lines cultured in normal conditions. These findings demonstrate that nuclear and cytosolic KG-dependent reactions may derive KG from functionally distinct subcellular pools and sources.

Mutations of RAS genes drive cancer more frequently than any other oncogene. RAS proteins integrate signals from a wide array of receptors and initiate downstream signaling through pathways that control cellular growth. RAS proteins are fundamentally binary molecular switches in which the off/on state is determined by the binding of GDP or GTP, respectively. As such, the intrinsic and regulated nucleotide-binding and hydrolytic properties of the RAS GTPase were historically believed to account for the entirety of the regulation of RAS signaling. However, it is increasingly clear that RAS proteins are also regulated by a vast array of post-translational modifications (PTMs). The current challenge is to understand what are the functional consequences of these modifications and which are physiologically relevant. Because PTMs are catalyzed by enzymes that may offer targets for drug discovery, the study of RAS PTMs has been a high priority for RAS biologists.

Protein-protein interactions between G protein-coupled receptors (GPCRs) can augment their functionality and increase the repertoire of signaling pathways they regulate. New therapeutics designed to modulate such interactions may allow for targeting of a specific GPCR activity, thus reducing potential for side effects. Dopamine receptor (DR) heteromers are promising candidates for targeted therapy of neurological conditions such as Parkinson's disease since current treatments can have severe side effects. To facilitate development of such therapies, it is necessary to identify the various DR binding partners. We report here a new interaction partner for DRD₂ and DRD₃, the orphan receptor G protein-coupled receptor 143 (GPR143), an atypical GPCR that plays multiple roles in pigment cells and is expressed in several regions of the brain. We previously demonstrated that the DRD₂/ DRD₃ antagonist pimozide also modulates GPR143 activity. Using confocal microscopy and two FRET methods, we observed that the DRs and GPR143 colocalize and interact at intracellular membranes. Furthermore, co-expression of wildtype GPR143 resulted in a 57% and 67% decrease in DRD₂ and DRD₃ activity, respectively, as determined by β-Arrestin recruitment assay. GPR143-DR dimerization may negatively modulate DR activity by changing affinity for dopamine or delaying delivery of the DRs to the plasma membrane.

YiiP is a secondary transporter that couples Zn2+ transport to the proton motive force. Structural studies of YiiP from prokaryotes and Znt8 from humans have revealed three different Zn2+ sites and a conserved homodimeric architecture. These structures define the inward-facing and outward-facing states that characterize the archetypal alternating access mechanism of transport. To study the effects of Zn2+ binding on the conformational transition, we use cryo-EM together with molecular dynamics simulation to compare structures of YiiP from Shewanella oneidensis in the presence and absence of Zn2+. To enable single-particle cryo-EM, we used a phage-display library to develop a Fab antibody fragment with high affinity for YiiP, thus producing a YiiP/Fab complex. To perform MD simulations, we developed a nonbonded dummy model for Zn2+ and validated its performance with known Zn2+-binding proteins. Using these tools, we find that, in the presence of Zn2+, YiiP adopts an inward-facing conformation consistent with that previously seen in tubular crystals. After removal of Zn2+ with high-affinity chelators, YiiP exhibits enhanced flexibility and adopts a novel conformation that appears to be intermediate between inward-facing and outward-facing states. This conformation involves closure of a hydrophobic gate that has been postulated to control access to the primary transport site. Comparison of several independent cryo-EM maps suggests that the transition from the inward-facing state is controlled by occupancy of a secondary Zn2+ site at the cytoplasmic membrane interface. This work enhances our understanding of individual Zn2+ binding sites and their role in the conformational dynamics that govern the transport cycle.

We measured the activities of epithelial Na channels (ENaC) and ROMK channels in the distal nephron of the mouse kidney and assessed their role in the process of K+ secretion under different physiological conditions. Under basal dietary conditions (0.5% K), ENaC activity, measured as amiloride-sensitive currents, was high in cells at the distal end of the distal convoluted tubule (DCT) and proximal end of the connecting tubule (CNT), a region we call the early CNT (CNTe). In more distal parts of the CNT (aldosterone-sensitive portion [CNTas]), these currents were minimal. This functional difference correlated with alterations in the intracellular location of ENaC, which was at or near the apical membrane in CNTe and more cytoplasmic in the CNTas. ROMK activity, measured as TPNQ-sensitive currents, was substantial in both segments. A mathematical model of the rat nephron suggested that K+ secretion by the CNTe predicted from these currents provides much of the urinary K+ required for K balance on this diet. In animals fed a K-deficient diet (0.1% K), both ENaC and ROMK currents in the CNTe decreased by ∼50%, predicting a 50% decline in K+ secretion. Enhanced reabsorption by a separate mechanism is required to avoid excessive urinary K+ losses. In animals fed a diet supplemented with 3% K, ENaC currents increased modestly in the CNTe but strongly in the CNTas, while ROMK currents tripled in both segments. The enhanced secretion of K+ by the CNTe and the recruitment of secretion by the CNTas account for the additional transport required for K balance. Therefore, adaptation to increased K+ intake involves the extension of robust K+ secretion to more distal parts of the nephron.

Advances in -omics analyses have tremendously enhanced our understanding of the role of the microbiome in human health and disease. Most research is focused on the bacteriome, but scientists have now realized the significance of the virome and microbial dysbiosis as well, particularly in noninfectious diseases such as cancer. In this review, we summarize the role of mycobiome in tumorigenesis, with a dismal prognosis, and attention to pancreatic ductal adenocarcinoma (PDAC). We also discuss bacterial and mycobial interactions to the host's immune response that is prevalently responsible for resistance to cancer therapy, including immunotherapy. We reported that the Malassezia species associated with scalp and skin infections, colonize in human PDAC tumors and accelerate tumorigenesis via activating the C3 complement-mannose-binding lectin (MBL) pathway. PDAC tumors thrive in an immunosuppressive microenvironment with desmoplastic stroma and a dysbiotic microbiome. Host-microbiome interactions in the tumor milieu pose a significant threat in driving the indolent immune behavior of the tumor. Microbial intervention in multimodal cancer therapy is a promising novel approach to modify an immunotolerant ("cold") tumor microenvironment to an immunocompetent ("hot") milieu that is effective in eliminating tumorigenesis.

OBJECTIVES/OBJECTIVE:To evaluate the outcomes of patients who underwent soft tissue flap coverage during treatment of a tibia fracture nonunion. DESIGN/METHODS:Retrospective analysis on prospectively collected data. SETTING/METHODS:Academic medical center. PATIENTS/PARTICIPANTS/METHODS:157 patients were treated for a fracture nonunion following a tibia fracture over a 15-year period. Sixty-six had sustained an open tibial fracture initially and 25 of these patients underwent soft tissue flaps for their open tibia fracture nonunion. INTERVENTION/METHODS:Manipulation of soft tissue flaps, either placement or elevation for graft placement in ununited previously open tibial fractures. MAIN OUTCOME MEASUREMENTS/METHODS:Bony healing, time to union, ultimate soft tissue status, postoperative complications, and functional outcome scores using the Short Musculoskeletal Functional Assessment (SMFA). This group was compared to a group of open tibial fracture nonunions that did not undergo soft tissue transfer. RESULTS:Bony healing was achieved in 24/25 patients (96.0%) who received flaps at a mean time to union of 8.7 ± 3.3 months compared to 39/41 patients (95.1%) at a mean 7.5 ± 3.2 months (p > 0.05) in the non-coverage group. Healing rate and time to union did not differ between groups. At latest follow-up, the flap coverage group reported a mean SMFA index of 17.1 compared to an SMFA index of 27.7 for the non-coverage group (p = 0.037). CONCLUSIONS:Utilization of soft tissue flaps in the setting of open tibia shaft nonunion repair surgery are associated with a high union rate (>90%). Coverage with or manipulation of soft tissue flaps did not result in improved bony healing rate or time to union compared to those who did not require flaps. However, soft tissue flap coverage was associated with higher functional scores at long-term follow-up. LEVEL OF EVIDENCE/METHODS:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.