Polycystins recruit cargo to distinct ciliary extracellular vesicle subtypes.

Therapeutic use of tiny extracellular vesicles (EVs) requires understanding cargo loading mechanisms. Here, we used a modular proximity label approach to identify EV cargo associated with the transient potential channel (TRP) polycystin PKD-2 of C. elegans. Polycystins are conserved receptor-TRP channel proteins affecting cilium function; dysfunction causes polycystic kidney disease in humans and mating deficits in C. elegans. Polycystin-2 EV localization is conserved from algae to humans, hinting at an ancient and unknown function. We discovered that polycystins associate with and direct specific cargo to EVs: channel-like PACL-1, dorsal and ventral membrane C-type lectins PAMLs, and conserved tumor necrosis-associated factor (TRAF) signaling adaptors TRF-1 and TRF-2. Loading of these components relied on polycystin-1 LOV-1. Our modular EV-TurboID approach can be applied in both cell- and tissue-specific manners to define the composition of distinct EV subtypes, addressing a major challenge of the EV field.

TAVR Beyond Fetal Viability: An Alternative to Preterm Delivery in Symptomatic Severe Aortic Stenosis.

A patient with structural valve degeneration of an aortic bioprosthesis with stenosis stage 3 underwent valve-in-valve transcatheter aortic valve replacement (TAVR) at 29 weeks with improvement. This is the first reported TAVR in the third trimester. TAVR may be an alternative to preterm delivery in cases of symptomatic aortic stenosis.

Human Cytomegalovirus in breast milk is associated with milk composition, the infant gut microbiome, and infant growth.

Human cytomegalovirus (CMV) is a highly prevalent herpesvirus that is often transmitted to the neonate via breast milk. Postnatal CMV transmission can have negative health consequences for preterm and immunocompromised infants, but any effects on healthy term infants are thought to be benign. Furthermore, the impact of CMV on the composition of the hundreds of bioactive factors in human milk has not been tested. Here, we utilize a cohort of exclusively breastfeeding full term mother-infant pairs to test for differences in the milk transcriptome and metabolome associated with CMV, and the impact of CMV in breast milk on the infant gut microbiome and infant growth. We find upregulation of the indoleamine 2,3- dioxygenase (IDO) tryptophan-to-kynurenine metabolic pathway in CMV+ milk samples, and that CMV+ milk is associated with decreased Bifidobacterium in the infant gut. Our data indicate a complex relationship between milk CMV, milk kynurenine, and infant growth; with kynurenine positively correlated, and CMV viral load negatively correlated, with infant weight-for-length at 1 month of age. These results suggest CMV transmission, CMV-related changes in milk composition, or both may be modulators of full term infant development.

Human milk variation is shaped by maternal genetics and impacts the infant gut microbiome.

Human milk is a complex mix of nutritional and bioactive components that provide complete nutrition for the infant. However, we lack a systematic knowledge of the factors shaping milk composition and how milk variation influences infant health. Here, we used multi-omic profiling to characterize interactions between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome in 242 exclusively breastfeeding mother-infant pairs. We identified 487 genetic loci associated with milk gene expression unique to the lactating mammary gland, including loci that impacted breast cancer risk and human milk oligosaccharide concentration. Integrative analyses uncovered connections between milk gene expression and infant gut microbiome, including an association between the expression of inflammation-related genes with IL-6 concentration in milk and the abundance of Bifidobacteria in the infant gut. Our results show how an improved understanding of the genetics and genomics of human milk connects lactation biology with maternal and infant health.

Bacterial, fungal, and interkingdom microbiome features of exclusively breastfeeding dyads are associated with infant age, antibiotic exposure, and birth mode.

The composition and function of early life gut bacterial communities (microbiomes) have been proposed to modulate health for the long term. In addition to bacteria, fungi (mycobiomes) also colonize the early life gut and have been implicated in health disorders such as asthma and obesity. Despite the potential importance of mycobiomes in health, there has been a lack of study regarding fungi and their interkingdom interactions with bacteria during infancy. The goal of this study was to obtain a more complete understanding of microbial communities thought to be relevant for the early life programming of health. Breastmilk and infant feces were obtained from a unique cohort of healthy, exclusively breastfeeding dyads recruited as part of the Mothers and Infants Linked for Healthy Growth (MILk) study with microbial taxa characterized using amplicon-based sequencing approaches. Bacterial and fungal communities in breastmilk were both distinct from those of infant feces, consistent with niche-specific microbial community development. Nevertheless, overlap was observed among sample types (breastmilk, 1-month feces, 6-month feces) with respect to the taxa that were the most prevalent and abundant. Self-reported antibacterial antibiotic exposure was associated with micro- as well as mycobiome variation, which depended upon the subject receiving antibiotics (mother or infant), timing of exposure (prenatal, peri- or postpartum), and sample type. In addition, birth mode was associated with bacterial and fungal community variation in infant feces, but not breastmilk. Correlations between bacterial and fungal taxa abundances were identified in all sample types. For infant feces, congruency between bacterial and fungal communities was higher for older infants, consistent with the idea of co-maturation of bacterial and fungal gut communities. Interkingdom connectedness also tended to be higher in older infants. Additionally, higher interkingdom connectedness was associated with Cesarean section birth and with antibiotic exposure for microbial communities of both breastmilk and infant feces. Overall, these results implicate infant age, birth mode, and antibiotic exposure in bacterial, fungal and interkingdom relationship variation in early-life-relevant microbiomes, expanding the current literature beyond bacteria.

Targeted secretion: Myosin V delivers vesicles through formin condensates.

Secretory vesicles are often delivered to very specific targets, like pre-synaptic terminals or cell tips, to focus exocytosis. New work suggests that a biomolecular condensate focuses actin filaments that deliver incoming vesicles through the condensate to the plasma membrane.

Mechanism of commitment to a mating partner in Saccharomyces cerevisiae.

Many cells detect and follow gradients of chemical signals to perform their functions. Yeast cells use gradients of extracellular pheromones to locate mating partners, providing a tractable model for understanding how cells decode the spatial information in gradients. To mate, yeast cells must orient polarity toward the mating partner. Polarity sites are mobile, exploring the cell cortex until they reach the proper position, where they stop moving and "commit" to the partner. A simple model to explain commitment posits that a high concentration of pheromone is detected only upon alignment of partner cells' polarity sites and causes polarity site movement to stop. Here we explore how yeast cells respond to partners that make different amounts of pheromone. Commitment was surprisingly robust to various pheromone levels, ruling out the simple model. We also tested whether adaptive pathways were responsible for the robustness of commitment, but our results show that cells lacking those pathways were still able to accommodate changes in pheromone. To explain this robustness, we suggest that the steep pheromone gradients near each mating partner's polarity site trap the polarity site in place.

Pheromone Guidance of Polarity Site Movement in Yeast.

Cells' ability to track chemical gradients is integral to many biological phenomena, including fertilization, development, accessing nutrients, and combating infection. Mating of the yeast Saccharomyces cerevisiae provides a tractable model to understand how cells interpret the spatial information in chemical gradients. Mating yeast of the two different mating types secrete distinct peptide pheromones, called a-factor and α-factor, to communicate with potential partners. Spatial gradients of pheromones are decoded to guide mobile polarity sites so that polarity sites in mating partners align towards each other, as a prerequisite for cell-cell fusion and zygote formation. In ascomycetes including S. cerevisiae, one pheromone is prenylated (a-factor) while the other is not (α-factor). The difference in physical properties between the pheromones, combined with associated differences in mechanisms of secretion and extracellular pheromone metabolism, suggested that the pheromones might differ in the spatial information that they convey to potential mating partners. However, as mating appears to be isogamous in this species, it is not clear why any such signaling difference would be advantageous. Here we report assays that directly track movement of the polarity site in each partner as a way to understand the spatial information conveyed by each pheromone. Our findings suggest that both pheromones convey very similar information. We speculate that the different pheromones were advantageous in ancestral species with asymmetric mating systems and may represent an evolutionary vestige in yeasts that mate isogamously.

Gestational Diabetes Mellitus Is Associated with Differences in Human Milk Hormone and Cytokine Concentrations in a Fully Breastfeeding United States Cohort.

It is unclear whether gestational diabetes mellitus (GDM) alters breast milk composition. We prospectively examined associations of GDM status with concentrations of six potentially bioactive elements (glucose, insulin, C-reactive protein (CRP), interleukin-6 (IL-6), leptin, and adiponectin) in human milk. These were measured at both 1 and 3 months postpartum in 189 fully breastfeeding women. Mixed-effects linear regression assessed GDM status-related differences in these milk bioactives, adjusting for demographics, maternal factors, and diet. At 1 and 3 months postpartum, milk CRP was higher (1.46 ± 0.31 ng/mL; p < 0.001 and 1.69 ± 0.31 ng/mL; p < 0.001) in women with GDM than in women without GDM, whereas milk glucose (−5.23 ± 2.22 mg/dL; p = 0.02 and −5.70 ± 2.22; p = 0.01) and milk insulin (−0.38 ± 0.17 µIU/mL; p = 0.03 and −0.53 ± 0.17; p = 0.003) were lower in women with GDM. These significant associations remained similar after additional adjustment for maternal weight status and its changes. No difference was found for milk IL-6, leptin, and adiponectin. There was no evidence of association between these milk bioactive compounds and 1 h non-fasting oral glucose challenge serum glucose in the women without GDM. This prospective study provides evidence that potentially bioactive elements of human milk composition are altered in women with GDM.

Chemotropism and Cell-Cell Fusion in Fungi.

Fungi exhibit an enormous variety of morphologies, including yeast colonies, hyphal mycelia, and elaborate fruiting bodies. This diversity arises through a combination of polar growth, cell division, and cell fusion. Because fungal cells are nonmotile and surrounded by a protective cell wall that is essential for cell integrity, potential fusion partners must grow toward each other until they touch and then degrade the intervening cell walls without impacting cell integrity. Here, we review recent progress on understanding how fungi overcome these challenges. Extracellular chemoattractants, including small peptide pheromones, mediate communication between potential fusion partners, promoting the local activation of core cell polarity regulators to orient polar growth and cell wall degradation. However, in crowded environments, pheromone gradients can be complex and potentially confusing, raising the question of how cells can effectively find their partners. Recent findings suggest that the cell polarity circuit exhibits searching behavior that can respond to pheromone cues through a remarkably flexible and effective strategy called exploratory polarization.

Gestational Diabetes Mellitus Is Associated with Altered Abundance of Exosomal MicroRNAs in Human Milk.

PURPOSE: Human milk (HM) is a unique biological fluid that is enriched with a variety of factors, including microRNAs (miRNAs) that potentially provide both short- and long-term benefits to the infants. miRNAs are packaged within exosomes, making them bioavailable to infants. Gestational diabetes mellitus (GDM) may affect the abundance of exosomal miRNAs in HM, providing a mechanism for growth and adiposity variation in infants of mothers with GDM in early life. Therefore, the purposes of this study were to examine the impact of GDM on select miRNAs (miRNA-148a, miRNA-30b, miRNA-let-7a, and miRNA-let-7d) involved in metabolism and to examine the association of these miRNAs with measures of infant body composition in the first 6 months of life. METHODS: Milk samples were collected from a cohort of 94 mothers (62 mothers without GDM and 32 mothers with GDM) matched on body mass index strata at 1 month post partum. miRNA abundance was measured by real-time polymerase chain reaction. Linear regression models were used to examine potential differences in miRNA abundance in women with and without GDM, testing associations between miRNA abundance and infant growth and body composition measures from 1 to 6 months. FINDINGS: The abundances of miRNA-148a, miRNA-30b, miRNA-let-7a, and miRNA-let-7d were reduced in milk from mothers with GDM. Independent of GDM status, higher maternal diet quality was associated with increased abundance of each of the measured miRNAs. miRNA-148a was negatively associated with infant weight, percentage of body fat, and fat mass, whereas miRNA-30b was positively associated with infant weight and fat mass at 1 month of age. There was no association of milk miRNA-148a and miRNA-30b with infant weight at 1 month of age or with body composition measures at 3 months of age; however, miRNA-148a was negatively associated with infant weight at 6 months of age. IMPLICATIONS: If supported by randomized dietary supplementation or other intervention trials, HM miRNAs may be a therapeutic target to mitigate risk of metabolic outcomes in offspring of women with GDM.

Chemotactic movement of a polarity site enables yeast cells to find their mates.

How small eukaryotic cells can interpret dynamic, noisy, and spatially complex chemical gradients to orient growth or movement is poorly understood. We address this question using Saccharomyces cerevisiae, where cells orient polarity up pheromone gradients during mating. Initial orientation is often incorrect, but polarity sites then move around the cortex in a search for partners. We find that this movement is biased by local pheromone gradients across the polarity site: that is, movement of the polarity site is chemotactic. A bottom-up computational model recapitulates this biased movement. The model reveals how even though pheromone-bound receptors do not mimic the shape of external pheromone gradients, nonlinear and stochastic effects combine to generate effective gradient tracking. This mechanism for gradient tracking may be applicable to any cell that searches for a target in a complex chemical landscape.

Chromosomal microarray analysis in the investigation of prenatally diagnosed congenital heart disease.

BACKGROUND: Chromosomal microarray analysis has emerged as a primary diagnostic tool in prenatally diagnosed congenital heart disease and other structural anomalies in clinical practice. OBJECTIVE: Our study aimed to investigate the diagnostic yield of microarray analysis as a first-tier test for chromosomal abnormalities in fetuses with both isolated and nonisolated congenital heart disease and to identify the association of different pathogenic chromosomal abnormalities with different subgroups of congenital heart disease. STUDY DESIGN: Retrospective data from 217 pregnancies that were diagnosed with congenital heart disease between 2011 and 2016 were reviewed. All pregnancies were investigated with the use of microarray analysis during the study period. Classification of chromosomal abnormalities was done based on American College of Medical Genetics and Genomics guidelines into (1) pathogenic chromosomal abnormalities that included numeric chromosomal abnormalities (aneuploidy and partial aneuploidy) and pathogenic copy number variants (22q11.2 deletion and other microdeletions/microduplications), (2) variants of uncertain significance, and (3) normal findings. RESULTS: Our study found a detection rate for pathogenic chromosomal abnormalities (numeric and pathogenic copy number variants) of 36.9% in pregnancies (n=80) that were diagnosed prenatally with congenital heart disease who underwent invasive testing with chromosomal microarray. The detection rate for numeric abnormalities was 29.5% (n=64) and for pathogenic copy number variants was 7.4% (n=16) of which 4.2% were 22q11.2 deletion and 3.2% were other pathogenic copy number variants, most of which theoretically could have been missed by the use of conventional karyotype alone. Pathogenic copy number variants were most common in conotruncal defects (19.6%; 11/56) that included 42.9% in cases of interrupted aortic arch, 23.8% in cases of tetralogy of Fallot, 13.3% in cases of transposition of the great arteries, and 8.3% in cases of double outlet right ventricle. Of these changes, 81.8% were 22q11.2 deletion, and 18.2% were other microdeletions/microduplications. After conotruncal defects, pathogenic copy number variants were most common in right ventricular outflow tract and left ventricular outflow tract groups (8% and 2.2%, respectively) in which none were 22q11.2 deletion. Pathogenic chromosomal abnormalities (numeric and pathogenic copy number variants) detected by chromosomal microarray analysis were significantly more common in the nonisolated congenital heart disease group (64.5%; n=49) compared with the isolated group (22%; n=31; P<.001). CONCLUSION: In pregnancies that were diagnosed with congenital heart disease and had undergone diagnostic genetic testing, our study showed that chromosomal microarray analysis has an added value in the detection of pathogenic chromosomal abnormalities compared with conventional karyotype, particularly in cases of pathogenic copy number variants. This yield is influenced not only by the type of congenital heart disease but also by the presence of extracardiac anomalies.

Preterm Birth of Infants Prenatally Diagnosed with Congenital Heart Disease, Characteristics, Associations, and Outcomes.

There are limited data on the relation between congenital heart disease (CHD) and preterm birth (PTB). We aimed to estimate the risk of PTB in newborns with CHD, to study associations and risk factors (modifiable and non-modifiable) as well as investigate postnatal outcomes. This was a retrospective cohort study of 336 pregnancies diagnosed with CHD between 2011 and 2016. Groups consisted of those delivered at or after 37 weeks, and those who delivered prior to 37 weeks. Collected data included maternal and fetal characteristics as well postnatal outcomes. Complete data were obtained from 237 singleton pregnancies. The overall proportion of PTB was 23.2% for all CHD, of which 38.2% were spontaneous PTB which was almost unchanged after excluding extracardiac anomalies and pathogenic chromosomal abnormalities. Significant non-modifiable risk factors were pregnancy-related HTN disorders (P < 0.001), fetal growth restriction (P = 0.01), and pathogenic chromosomal abnormalities (P = 0.046). Significant PTB modifiable risk factors included prenatal marijuana use (P = 0.01). Pregnancies delivered at 37-38 weeks had significantly more newborns with birthweight < 2500 g (P < 0.001), required more pre-operative NICU support including intubation (P = 0.049), vasopressors (P = 0.04), prostaglandins (P = 0.003), antibiotics (P = 0.01), and had longer hospital stay (P = 0.001) than those delivered at ≥ 39 weeks. Prenatally diagnosed pregnancies with CHD had higher PTB rate compared to the general population, with spontaneous PTB comprising 38.2% of these preterm deliveries. Most PTB risk factors were non-modifiable, however, significant modifiable factors included marijuana use in pregnancy. Outcomes were favorable in neonates delivered at or beyond 39 weeks.

Fetal Nasal Bone Length in the East African Population.

OBJECTIVES: To establish normal ranges of fetal nasal bone length throughout gestation in the East African population and to subsequently compare these measurements with the standardized reference. METHODS: A retrospective cross-sectional study was performed at the University of Minnesota from January 2011 to December 2016. Fetal nasal bone length measurements were generated in a midsagittal plane at an angle of insonation of 45° from ultrasound images of 1407 nonanomalous fetuses of 1130 mothers of East African decent between 14 and 40 weeks' gestation. The proportion of fetal nasal bone lengths of less than 5.2 mm at week 20 of gestation in the East African population was then compared with the 5% noted by the standardized reference by a χ2 test. RESULTS: The fetal nasal bone length increased linearly with advancing gestational age in fetuses of East African mothers (R2 = 0.53; P < .0001). The fetal nasal bone lengths of the East African fetuses were found to be shorter at all ages of gestation compared with the standard reference. At 20 weeks' gestation 17% (95% confidence interval, 13%-22%) of the nasal bone lengths of the East African fetuses were less than 5.2 mm compared with 5% of white and African American fetuses. CONCLUSIONS: Using the standard reference may lead to a greater than 3.5-fold overdiagnosis of hypoplastic nasal bones in the East African population. To improve aneuploidy risk stratification and patient counseling in the East African population, the introduction of a standardized East African-based fetal nasal bone length reference seems warranted.

Mating in wild yeast: delayed interest in sex after spore germination.

Studies of laboratory strains of Saccharomyces cerevisiae have uncovered signaling pathways involved in mating, including information-processing strategies to optimize decisions to mate or to bud. However, lab strains are heterothallic (unable to self-mate), while wild yeast are homothallic. And while mating of lab strains is studied using cycling haploid cells, mating of wild yeast is thought to involve germinating spores. Thus, it was unclear whether lab strategies would be appropriate in the wild. Here, we have investigated the behavior of several yeast strains derived from wild isolates. Following germination, these strains displayed large differences in their propensity to mate or to enter the cell cycle. The variable interest in sex following germination was correlated with differences in pheromone production, which were due to both cis- and trans-acting factors. Our findings suggest that yeast spores germinating in the wild may often enter the cell cycle and form microcolonies before engaging in mating.

Home Monitoring for Fetal Heart Rhythm During Anti-Ro Pregnancies.

BACKGROUND: Fetal atrioventricular block (AVB) occurs in 2% to 4% of anti-Ro antibody-positive pregnancies and can develop in <24 h. Only rarely has standard fetal heart rate surveillance detected AVB in time for effective treatment. OBJECTIVES: Outcome of anti-Ro pregnancies was surveilled with twice-daily home fetal heart rate and rhythm monitoring (FHRM) and surveillance echocardiography. METHODS: Anti-Ro pregnant women were recruited from 16 international centers in a prospective observational study. Between 18 and 26 weeks' gestation, mothers checked FHRM twice daily with a commercially available Doppler monitor and underwent weekly or biweekly surveillance fetal echocardiograms. If FHRM was abnormal, a diagnostic echocardiogram was performed. Cardiac cycle length and atrioventricular interval were measured, and cardiac function was assessed on all echocardiograms. After 26 weeks, home FHRM and echocardiograms were discontinued, and mothers were monitored during routine obstetrical visits. Postnatal electrocardiograms were performed. RESULTS: Most mothers (273 of 315, 87%) completed the monitoring protocol, generating 1,752 fetal echocardiograms. Abnormal FHRM was detected in 21 mothers (6.7%) who sought medical attention >12 h (n = 7), 3 to 12 h (n = 9), or <3 h (n = 5) after abnormal FHRM. Eighteen fetuses had benign rhythms, and 3 had second- or third-degree AVB. Treatment of second-degree AVB <12 h after abnormal FHRM restored sinus rhythm. Four fetuses had first-degree AVB diagnosed by echocardiography; none progressed to second-degree AVB. No AVB was missed by home FHRM or developed after FHRM. CONCLUSIONS: Home FHRM confirms the rapid progression of normal rhythm to AVB and can define a window of time for successful therapy. (Prospective Maternal Surveillance of SSA [Sjögren Syndrome A] Positive Pregnancies Using a Hand-held Fetal Heart Rate Monitor; NCT02920346).

Asterless is required for centriole length control and sperm development.

Centrioles are the foundation of two organelles, centrosomes and cilia. Centriole numbers and functions are tightly controlled, and mutations in centriole proteins are linked to a variety of diseases, including microcephaly. Loss of the centriole protein Asterless (Asl), the Drosophila melanogaster orthologue of Cep152, prevents centriole duplication, which has limited the study of its nonduplication functions. Here, we identify populations of cells with Asl-free centrioles in developing Drosophila tissues, allowing us to assess its duplication-independent function. We show a role for Asl in controlling centriole length in germline and somatic tissue, functioning via the centriole protein Cep97. We also find that Asl is not essential for pericentriolar material recruitment or centrosome function in organizing mitotic spindles. Lastly, we show that Asl is required for proper basal body function and spermatid axoneme formation. Insights into the role of Asl/Cep152 beyond centriole duplication could help shed light on how Cep152 mutations lead to the development of microcephaly.