Sodium-Glucose Cotransporter 2 Inhibitors and Mycotic Genital or Urinary Tract Infections in Heart Failure.

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) improve clinical outcomes in persons with heart failure (HF). This class of agents has been consistently associated with an increased risk of mycotic genital infections (MGIs), and in some, but not all, trials, urinary tract infections (UTIs). Other medications widely used for cardiac conditions do not cause MGIs and UTIs, so cardiologists and their supporting teams will be encountering clinical questions that they previously did not have to address. This review provides clinicians with practical recommendations about SGLT2i use in individuals with HF as related to the associated MGI and possible UTI risks. Overall, given the benefit of SGLT2is in clinical outcomes, the threshold for not initiating or discontinuing SGLT2is due to concerns for MGIs or UTIs should be high for persons with HF. Likewise, when SGLT2is are discontinued for such concerns, the threshold for reinitiation should be low.

Reconstructed evolutionary history of the yeast septins Cdc11 and Shs1.

Septins are GTP-binding proteins conserved across metazoans. They can polymerize into extended filaments and, hence, are considered a component of the cytoskeleton. The number of individual septins varies across the tree of life-yeast (Saccharomyces cerevisiae) has seven distinct subunits, a nematode (Caenorhabditis elegans) has two, and humans have 13. However, the overall geometric unit (an apolar hetero-octameric protomer and filaments assembled there from) has been conserved. To understand septin evolutionary variation, we focused on a related pair of yeast subunits (Cdc11 and Shs1) that appear to have arisen from gene duplication within the fungal clade. Either Cdc11 or Shs1 occupies the terminal position within a hetero-octamer, yet Cdc11 is essential for septin function and cell viability, whereas Shs1 is not. To discern the molecular basis of this divergence, we utilized ancestral gene reconstruction to predict, synthesize, and experimentally examine the most recent common ancestor ("Anc.11-S") of Cdc11 and Shs1. Anc.11-S was able to occupy the terminal position within an octamer, just like the modern subunits. Although Anc.11-S supplied many of the known functions of Cdc11, it was unable to replace the distinct function(s) of Shs1. To further evaluate the history of Shs1, additional intermediates along a proposed trajectory from Anc.11-S to yeast Shs1 were generated and tested. We demonstrate that multiple events contributed to the current properties of Shs1: (1) loss of Shs1-Shs1 self-association early after duplication, (2) co-evolution of heterotypic Cdc11-Shs1 interaction between neighboring hetero-octamers, and (3) eventual repurposing and acquisition of novel function(s) for its C-terminal extension domain. Thus, a pair of duplicated proteins, despite constraints imposed by assembly into a highly conserved multi-subunit structure, could evolve new functionality via a complex evolutionary pathway.

Premature epiphyseal growth plate arrest after isotretinoin therapy for high-risk neuroblastoma: A case series and review of the literature.

BACKGROUND: Vitamin A-derived retinoids have been reported to cause skeletal abnormalities ranging from hypercalcemia to premature epiphyseal closure. Isotretinoin is a retinoid used as standard therapy for high-risk neuroblastoma and has been reported to cause premature epiphyseal growth plate arrest. PROCEDURE: We identified patients from the Children's Hospital Los Angeles (CHLA) database with high-risk neuroblastoma diagnosed from 1991 to 2018 who experienced premature epiphyseal growth plate arrest and compared their characteristics to other patients with high-risk neuroblastoma. We then performed a literature review of this complication. Data collection included diagnosis age of neuroblastoma, presentation age, agent of exposure, dose, exposure range, and skeletal deformity. RESULTS: Among 216 patients, high-risk neuroblastoma was diagnosed before age of five years (n = 165), between ages of 5 and 10 years (n = 41), and after 10 years of age (n = 13). Three out of 216 patients developed premature epiphyseal growth arrest after isotretinoin exposure (overall incidence = 1.38%). The incidence of bony abnormalities was significantly higher in patients diagnosed in 5- to 10-year age group than in other two groups (P = 0.014). Literature review identified eight additional patients with neuroblastoma who presented with retinoid associated skeletal abnormalities. The median range of isotretinoin exposure for these 11 patients was between 6.5 and 7.625 years (range, 2-14) with no cases of isotretinoin therapy completion before age 5 years. CONCLUSION: Bone toxicity associated with isotretinoin exposure is a concern. Growth plate arrest is a serious adverse effect that is attributable to isotretinoin therapy. Our findings suggest the prepubescent growth plate may be most at risk, and we recommend special attention to this population.

Pneumothorax presentation in endometrial sarcoma patients receiving chemotherapy: A case series.

Endometrial stromal sarcomas (ESS) account for 10-15% of uterine malignancies and are classified into four categories: endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LG-ESS), high-grade endometrial stromal sarcoma (HG-ESS) and undifferentiated uterine sarcoma (USS). Depending on stage, ESS is treated with surgery, hormone therapy, chemotherapy or targeted therapy. A rare complication of ESS with metastatic pulmonary disease is recurrent, bilateral pneumothoraces. The current literature has reported on patients with ESS who either presented with pneumothoraces at their initial diagnosis, and thus were untreated, or after treatment with surgical resection and hormone therapy. There have been no case reports of patients with ESS who presented with pneumothoraces while receiving chemotherapy. Furthermore, there have been no reported cases of patients with HG-ESS presenting with this rare complication. We would like to expand the literature by reporting on two patients with HG-ESS who presented with pneumothoraces while concurrently receiving chemotherapy.

Detection of protein-protein interactions at the septin collar in Saccharomyces cerevisiae using a tripartite split-GFP system.

Various methods can provide a readout of the physical interaction between two biomolecules. A recently described tripartite split-GFP system has the potential to report by direct visualization via a fluorescence signal the intimate association of minimally tagged proteins expressed at their endogenous level in their native cellular milieu and can capture transient or weak interactions. Here we document the utility of this tripartite split-GFP system to assess in living cells protein-protein interactions in a dynamic cytoskeletal structure-the septin collar at the yeast bud neck. We show, first, that for septin-septin interactions, this method yields a robust signal whose strength reflects the known spacing between the subunits in septin filaments and thus serves as a "molecular ruler." Second, the method yields little or no spurious signal even with highly abundant cytosolic proteins readily accessible to the bud neck (including molecular chaperone Hsp82 and glycolytic enzyme Pgk1). Third, using two proteins (Bni5 and Hsl1) that have been shown by other means to bind directly to septins at the bud neck in vivo, we validate that the tripartite split-GFP method yields the same conclusions and further insights about specificity. Finally, we demonstrate the capacity of this approach to uncover additional new information by examining whether three other proteins reported to localize to the bud neck (Nis1, Bud4, and Hof1) are able to interact physically with any of the subunits in the septin collar and, if so, with which ones.

Coordinate action of distinct sequence elements localizes checkpoint kinase Hsl1 to the septin collar at the bud neck in Saccharomyces cerevisiae.

Passage through the eukaryotic cell cycle requires processes that are tightly regulated both spatially and temporally. Surveillance mechanisms (checkpoints) exert quality control and impose order on the timing and organization of downstream events by impeding cell cycle progression until the necessary components are available and undamaged and have acted in the proper sequence. In budding yeast, a checkpoint exists that does not allow timely execution of the G2/M transition unless and until a collar of septin filaments has properly assembled at the bud neck, which is the site where subsequent cytokinesis will occur. An essential component of this checkpoint is the large (1518-residue) protein kinase Hsl1, which localizes to the bud neck only if the septin collar has been correctly formed. Hsl1 reportedly interacts with particular septins; however, the precise molecular determinants in Hsl1 responsible for its recruitment to this cellular location during G2 have not been elucidated. We performed a comprehensive mutational dissection and accompanying image analysis to identify the sequence elements within Hsl1 responsible for its localization to the septins at the bud neck. Unexpectedly, we found that this targeting is multipartite. A segment of the central region of Hsl1 (residues 611-950), composed of two tandem, semiredundant but distinct septin-associating elements, is necessary and sufficient for binding to septin filaments both in vitro and in vivo. However, in addition to 611-950, efficient localization of Hsl1 to the septin collar in the cell obligatorily requires generalized targeting to the cytosolic face of the plasma membrane, a function normally provided by the C-terminal phosphatidylserine-binding KA1 domain (residues 1379-1518) in Hsl1 but that can be replaced by other, heterologous phosphatidylserine-binding sequences.

The Carboxy-Terminal Tails of Septins Cdc11 and Shs1 Recruit Myosin-II Binding Factor Bni5 to the Bud Neck in Saccharomyces cerevisiae.

UNLABELLED: Septins are a conserved family of GTP-binding proteins that form heterooctameric complexes that assemble into higher-order structures. In yeast, septin superstructure at the bud neck serves as a barrier to separate a daughter cell from its mother and as a scaffold to recruit the proteins that execute cytokinesis. However, how septins recruit specific factors has not been well characterized. In the accompanying article in this issue, (Finnigan et al. 2015), we demonstrated that the C-terminal extensions (CTEs) of the alternative terminal subunits of septin heterooctamers, Cdc11 and Shs1, share a role required for optimal septin function in vivo. Here we describe our use of unbiased genetic approaches (both selection of dosage suppressors and analysis of synthetic interactions) that pinpointed Bni5 as a protein that interacts with the CTEs of Cdc11 and Shs1. Furthermore, we used three independent methods-construction of chimeric proteins, noncovalent tethering mediated by a GFP-targeted nanobody, and imaging by fluorescence microscopy-to confirm that a physiologically important function of the CTEs of Cdc11 and Shs1 is optimizing recruitment of Bni5 and thereby ensuring efficient localization at the bud neck of Myo1, the type II myosin of the actomyosin contractile ring.Related article in GENETICS: Finnigan, G. C. et al., 2015 Comprehensive Genetic Analysis of Paralogous Terminal Septin Subunits Shs1 and Cdc11 in Saccharomyces cerevisiae. Genetics 200: 841-861.