SARS-CoV-2 replication in airway epithelia requires motile cilia and microvillar reprogramming.

How SARS-CoV-2 penetrates the airway barrier of mucus and periciliary mucins to infect nasal epithelium remains unclear. Using primary nasal epithelial organoid cultures, we found that the virus attaches to motile cilia via the ACE2 receptor. SARS-CoV-2 traverses the mucus layer, using motile cilia as tracks to access the cell body. Depleting cilia blocks infection for SARS-CoV-2 and other respiratory viruses. SARS-CoV-2 progeny attach to airway microvilli 24 h post-infection and trigger formation of apically extended and highly branched microvilli that organize viral egress from the microvilli back into the mucus layer, supporting a model of virus dispersion throughout airway tissue via mucociliary transport. Phosphoproteomics and kinase inhibition reveal that microvillar remodeling is regulated by p21-activated kinases (PAK). Importantly, Omicron variants bind with higher affinity to motile cilia and show accelerated viral entry. Our work suggests that motile cilia, microvilli, and mucociliary-dependent mucus flow are critical for efficient virus replication in nasal epithelia.

Plant YTHDF proteins are direct effectors of antiviral immunity against an N6-methyladenosine-containing RNA virus.

In virus-host interactions, nucleic acid-directed first lines of defense that allow viral clearance without compromising growth are of paramount importance. Plants use the RNA interference pathway as a basal antiviral immune system, but additional RNA-based mechanisms of defense also exist. The infectivity of a plant positive-strand RNA virus, alfalfa mosaic virus (AMV), relies on the demethylation of viral RNA by the recruitment of the cellular N6-methyladenosine (m6 A) demethylase ALKBH9B, but how demethylation of viral RNA promotes AMV infection remains unknown. Here, we show that inactivation of the Arabidopsis cytoplasmic YT521-B homology domain (YTH)-containing m6 A-binding proteins ECT2, ECT3, and ECT5 is sufficient to restore AMV infectivity in partially resistant alkbh9b mutants. We further show that the antiviral function of ECT2 is distinct from its previously demonstrated function in the promotion of primordial cell proliferation: an ect2 mutant carrying a small deletion in its intrinsically disordered region is partially compromised for antiviral defense but not for developmental functions. These results indicate that the m6 A-YTHDF axis constitutes a novel branch of basal antiviral immunity in plants.

Evidence for an RNAi-independent role of Arabidopsis DICER-LIKE2 in growth inhibition and basal antiviral resistance.

Flowering plant genomes encode four or five DICER-LIKE (DCL) enzymes that produce small interfering RNAs (siRNAs) and microRNAs, which function in RNA interference (RNAi). Different RNAi pathways in plants effect transposon silencing, antiviral defense, and endogenous gene regulation. DCL2 acts genetically redundantly with DCL4 to confer basal antiviral defense. However, DCL2 may also counteract DCL4 since knockout of DCL4 causes growth defects that are suppressed by DCL2 inactivation. Current models maintain that RNAi via DCL2-dependent siRNAs is the biochemical basis of both effects. Here, we report that DCL2-mediated antiviral resistance and growth defects cannot be explained by the silencing effects of DCL2-dependent siRNAs. Both functions are defective in genetic backgrounds that maintain high levels of DCL2-dependent siRNAs, either with specific point mutations in DCL2 or with reduced DCL2 dosage because of heterozygosity for dcl2 knockout alleles. Intriguingly, all DCL2 functions require its catalytic activity, and the penetrance of DCL2-dependent growth phenotypes in dcl4 mutants correlates with DCL2 protein levels but not with levels of major DCL2-dependent siRNAs. We discuss this requirement and correlation with catalytic activity but not with resulting siRNAs, in light of other findings that reveal a DCL2 function in innate immunity activation triggered by cytoplasmic double-stranded RNA.

Insights into the conservation and diversification of the molecular functions of YTHDF proteins.

YT521-B homology (YTH) domain proteins act as readers of N6-methyladenosine (m6A) in mRNA. Members of the YTHDF clade determine properties of m6A-containing mRNAs in the cytoplasm. Vertebrates encode three YTHDF proteins whose possible functional specialization is debated. In land plants, the YTHDF clade has expanded from one member in basal lineages to eleven so-called EVOLUTIONARILY CONSERVED C-TERMINAL REGION1-11 (ECT1-11) proteins in Arabidopsis thaliana, named after the conserved YTH domain placed behind a long N-terminal intrinsically disordered region (IDR). ECT2, ECT3 and ECT4 show genetic redundancy in stimulation of primed stem cell division, but the origin and implications of YTHDF expansion in higher plants are unknown, as it is unclear whether it involves acquisition of fundamentally different molecular properties, in particular of their divergent IDRs. Here, we use functional complementation of ect2/ect3/ect4 mutants to test whether different YTHDF proteins can perform the same function when similarly expressed in leaf primordia. We show that stimulation of primordial cell division relies on an ancestral molecular function of the m6A-YTHDF axis in land plants that is present in bryophytes and is conserved over YTHDF diversification, as it appears in all major clades of YTHDF proteins in flowering plants. Importantly, although our results indicate that the YTH domains of all arabidopsis ECT proteins have m6A-binding capacity, lineage-specific neo-functionalization of ECT1, ECT9 and ECT11 happened after late duplication events, and involves altered properties of both the YTH domains, and, especially, of the IDRs. We also identify two biophysical properties recurrent in IDRs of YTHDF proteins able to complement ect2 ect3 ect4 mutants, a clear phase separation propensity and a charge distribution that creates electric dipoles. Human and fly YTHDFs do not have IDRs with this combination of properties and cannot replace ECT2/3/4 function in arabidopsis, perhaps suggesting different molecular activities of YTHDF proteins between major taxa.

A YTHDF-PABP interaction is required for m6 A-mediated organogenesis in plants.

N6-methyladenosine (m6 A) in mRNA is key to eukaryotic gene regulation. Many m6 A functions involve RNA-binding proteins that recognize m6 A via a YT521-B Homology (YTH) domain. YTH domain proteins contain long intrinsically disordered regions (IDRs) that may mediate phase separation and interaction with protein partners, but whose precise biochemical functions remain largely unknown. The Arabidopsis thaliana YTH domain proteins ECT2, ECT3, and ECT4 accelerate organogenesis through stimulation of cell division in organ primordia. Here, we use ECT2 to reveal molecular underpinnings of this function. We show that stimulation of leaf formation requires the long N-terminal IDR, and we identify two short IDR elements required for ECT2-mediated organogenesis. Of these two, a 19-amino acid region containing a tyrosine-rich motif conserved in both plant and metazoan YTHDF proteins is necessary for binding to the major cytoplasmic poly(A)-binding proteins PAB2, PAB4, and PAB8. Remarkably, overexpression of PAB4 in leaf primordia partially rescues the delayed leaf formation in ect2 ect3 ect4 mutants, suggesting that the ECT2-PAB2/4/8 interaction on target mRNAs of organogenesis-related genes may overcome limiting PAB concentrations in primordial cells.

Non-coding region variants upstream of MEF2C cause severe developmental disorder through three distinct loss-of-function mechanisms.

Clinical genetic testing of protein-coding regions identifies a likely causative variant in only around half of developmental disorder (DD) cases. The contribution of regulatory variation in non-coding regions to rare disease, including DD, remains very poorly understood. We screened 9,858 probands from the Deciphering Developmental Disorders (DDD) study for de novo mutations in the 5' untranslated regions (5' UTRs) of genes within which variants have previously been shown to cause DD through a dominant haploinsufficient mechanism. We identified four single-nucleotide variants and two copy-number variants upstream of MEF2C in a total of ten individual probands. We developed multiple bespoke and orthogonal experimental approaches to demonstrate that these variants cause DD through three distinct loss-of-function mechanisms, disrupting transcription, translation, and/or protein function. These non-coding region variants represent 23% of likely diagnoses identified in MEF2C in the DDD cohort, but these would all be missed in standard clinical genetics approaches. Nonetheless, these variants are readily detectable in exome sequence data, with 30.7% of 5' UTR bases across all genes well covered in the DDD dataset. Our analyses show that non-coding variants upstream of genes within which coding variants are known to cause DD are an important cause of severe disease and demonstrate that analyzing 5' UTRs can increase diagnostic yield. We also show how non-coding variants can help inform both the disease-causing mechanism underlying protein-coding variants and dosage tolerance of the gene.

HIV infection is associated with a less aggressive phenotype of inflammatory bowel disease. A multicenter study of the ENEIDA registry.

BACKGROUND: The coexistence of human immunodeficiency virus (HIV) infection and inflammatory bowel disease (IBD) is uncommon. Data on the impact of HIV on IBD course and its management is scarce. AIM: To describe the IBD phenotype, therapeutic requirements and prevalence of opportunistic infections (OI) in IBD patients with a coexistent HIV infection. METHODS: Case-control, retrospective study including all HIV positive patients diagnosed with IBD in the ENEIDA registry. Patients with positive HIV serology (HIV-IBD) were compared to controls (HIV seronegative), matched 1:3 by year of IBD diagnosis, age, gender and type of IBD. RESULTS: A total of 364 patients (91 HIV-IBD and 273 IBD controls) were included. In the whole cohort, 58% had ulcerative colitis (UC), 35% had Crohn's disease (CD) and 7% were IBD unclassified. The HIV-IBD group presented a significantly higher proportion of proctitis in UC and colonic location in CD but fewer extraintestinal manifestations than controls. Regarding treatments, non-biological therapies (37.4% vs. 57.9%; P=0.001) and biologicals (26.4% vs. 42.1%; P=0.007), were used less frequently among patients in the HIV-IBD group. Conversely, HIV-IBD patients developed more OI than controls regardless of non-biological therapies use. In the multivariate analysis, HIV infection (OR 4.765, 95%CI 2.48-9.14; P<0.001) and having ≥1 comorbidity (OR 2.445, 95%CI 1.23-4.85; P=0.010) were risk factors for developing OI, while CD was protective (OR 0.372, 95%CI 0.18-0.78;P=0.009). CONCLUSIONS: HIV infection appears to be associated with a less aggressive phenotype of IBD and a lesser use of non-biological therapies and biologicals but entails a greater risk of developing OI.

Hormonal profiles and biomarkers leading to parturition in cattle.

This study aimed to understand the physiological mechanisms regulating parturition and to identify potential biomarkers to predict onset of birth. Additionally, we compared hormone profiles between cows with shorter and longer gestation lengths. Twenty-eight days before due date until 3d postpartum, cows (n = 18) were blood sampled daily. Circulating concentrations were measured for progesterone (P4) and estradiol (E2) by RIA, testosterone, prostaglandin F2α metabolite (PGFM), cortisol, pregnancy-specific protein B (PSPB) by ELISA and lactate concentrations by colorimetric assay. At end of gestation, P4 decreased from d-14 to d-4 (from 3.6 to 1.4 ng/mL), most likely from rapid loss of placental P4 production (64% of decline in 24 h). A second rapid decrease in P4 to undetectable concentrations was observed from d-2 to parturition (from 1.4 to 0.1 ng/ml; most likely luteal origin) corresponding to increase in PGFM from d-2 to parturition (249.7 to 2868.4 pg/mL). Estradiol and PSPB increased ~8-fold from ~13d before parturition with acute rise in E2 but not PSPB (45% vs 13% in first 24 h). Testosterone decreased slightly during the same period. Cortisol and lactate increased only at calving. Comparison of cows with shorter vs longer gestation, when data were normalized to parturition day, a difference was detected in circulating E2 and PGFM patterns, but not P4 and PSPB. Thus, the first significant hormonal changes associated with parturition begin at d-14 with E2 and PSPB as two clear biomarkers of impending parturition. Cows with shorter and longer gestation had hormonal differences indicative of identifiable earlier placental maturation.

Persistence of human respiratory viral RNA in wastewater-settled solids.

Wastewater-based epidemiology has emerged as a valuable tool for monitoring respiratory viral diseases within communities by analyzing concentrations of viral nucleic-acids in wastewater. However, little is known about the fate of respiratory virus nucleic-acids in wastewater. Two important fate processes that may modulate their concentrations in wastewater as they move from household drains to the point of collection include sorption or partitioning to wastewater solids and degradation. This study investigated the decay kinetics of genomic nucleic-acids of seven human respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respiratory syncytial virus (RSV), human coronavirus (HCoV)-OC43, HCoV-229E, HCoV-NL63, human rhinovirus (HRV), and influenza A virus (IAV), as well as pepper mild mottle virus (PMMoV) in wastewater solids. Viruses (except for PMMoV) were spiked into wastewater solids and their concentrations were followed for 50 days at three different temperatures (4°C, 22°C, and 37°C). Viral genomic RNA decayed following first-order kinetics with decay rate constants k from 0 to 0.219 per day. Decay rate constants k were not different from 0 for all targets in solids incubated at 4°C; k values were largest at 37°C and at this temperature, k values were similar across nucleic-acid targets. Regardless of temperature, there was limited viral RNA decay, with an estimated 0% to 20% reduction, over the typical residence times of sewage in the piped systems between input and collection point (<1 day). The k values reported herein can be used directly in fate and transport models to inform the interpretation of measurements made during wastewater surveillance.IMPORTANCEUnderstanding whether or not the RNA targets quantified for wastewater-based epidemiology (WBE) efforts decay during transport between drains and the point of sample collection is critical for data interpretation. Here we show limited decay of viral RNA targets typically measured for respiratory disease WBE.

Dissecting genetics of spectrum of epilepsies with eyelid myoclonia by exome sequencing.

OBJECTIVE: Epilepsy with eyelid myoclonia (EEM) spectrum is a generalized form of epilepsy characterized by eyelid myoclonia with or without absences, eye closure-induced seizures with electroencephalographic paroxysms, and photosensitivity. Based on the specific clinical features, age at onset, and familial occurrence, a genetic cause has been postulated. Pathogenic variants in CHD2, SYNGAP1, NEXMIF, RORB, and GABRA1 have been reported in individuals with photosensitivity and eyelid myoclonia, but whether other genes are also involved, or a single gene is uniquely linked with EEM, or its subtypes, is not yet known. We aimed to dissect the genetic etiology of EEM. METHODS: We studied a cohort of 105 individuals by using whole exome sequencing. Individuals were divided into two groups: EEM- (isolated EEM) and EEM+ (EEM accompanied by intellectual disability [ID] or any other neurodevelopmental/psychiatric disorder). RESULTS: We identified nine variants classified as pathogenic/likely pathogenic in the entire cohort (8.57%); among these, eight (five in CHD2, one in NEXMIF, one in SYNGAP1, and one in TRIM8) were found in the EEM+ subcohort (28.57%). Only one variant (IFIH1) was found in the EEM- subcohort (1.29%); however, because the phenotype of the proband did not fit with published data, additional evidence is needed before considering IFIH1 variants and EEM- an established association. Burden analysis did not identify any single burdened gene or gene set. SIGNIFICANCE: Our results suggest that for EEM, as for many other epilepsies, the identification of a genetic cause is more likely with comorbid ID and/or other neurodevelopmental disorders. Pathogenic variants were mostly found in CHD2, and the association of CHD2 with EEM+ can now be considered a reasonable gene-disease association. We provide further evidence to strengthen the association of EEM+ with NEXMIF and SYNGAP1. Possible new associations between EEM+ and TRIM8, and EEM- and IFIH1, are also reported. Although we provide robust evidence for gene variants associated with EEM+, the core genetic etiology of EEM- remains to be elucidated.

Evaluation of the Importance of Capsule Transparency in Dry Powder Inhalation Devices.

The aim of this work is to test whether the use of a transparent capsule affects the residual capsule weight after inhalation as a surrogate of the inhaled delivered dose for patients with non-reversible chronic airway disease. Researchers conducted an observational cross-sectional study with patients using a single-dose dry powder inhaler. The weight of the capsule was measured with a precision microbalance before and after inhalation. Ninety-one patients were included, of whom 63 (69.2%) used a transparent capsule. Inhalation with a transparent capsule achieved a weight decrease of 30.1% vs 8.6% for devices with an opaque capsule (P <0.001). These data reinforce the need to provide patients with mechanisms that verify the correct inhalation technique.

Nuclear and cytoplasmic RNA exosomes and PELOTA1 prevent miRNA-induced secondary siRNA production in Arabidopsis.

Amplification of short interfering RNA (siRNAs) via RNA-dependent RNA polymerases (RdRPs) is of fundamental importance in RNA silencing. Plant microRNA (miRNA) action generally does not involve engagement of RdRPs, in part thanks to a poorly understood activity of the cytoplasmic exosome adaptor SKI2. Here, we show that inactivation of the exosome subunit RRP45B and SKI2 results in similar patterns of miRNA-induced siRNA production. Furthermore, loss of the nuclear exosome adaptor HEN2 leads to secondary siRNA production from miRNA targets largely distinct from those producing siRNAs in ski2. Importantly, mutation of the Release Factor paralogue PELOTA1 required for subunit dissociation of stalled ribosomes causes siRNA production from miRNA targets overlapping with, but distinct from, those affected in ski2 and rrp45b mutants. We also show that in exosome mutants, miRNA targets can be sorted into producers and non-producers of illicit secondary siRNAs based on trigger miRNA levels and miRNA:target affinity rather than on presence of 5'-cleavage fragments. We propose that stalled RNA-Induced Silencing Complex (RISC) and ribosomes, but not mRNA cleavage fragments released from RISC, trigger siRNA production, and that the exosome limits siRNA amplification by reducing RISC dwell time on miRNA target mRNAs while PELOTA1 does so by reducing ribosome stalling.

Selective serotonin reuptake inhibitors during pregnancy and lactation: A scoping review of effects on the maternal and infant gut microbiome.

Perinatal mood disorders are a tremendous burden to childbearing families and treatment with selective serotonin reuptake inhibitor (SSRI) antidepressants is increasingly common. Exposure to SSRIs may affect serotonin signaling and ultimately, microbes that live in the gut. Health of the gut microbiome during pregnancy, lactation, and early infancy is critical, yet there is limited evidence to describe the relationship between SSRI exposure and gut microbiome status in this population. The purpose of this Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)-compliant scoping review is to assess evidence and describe key concepts regarding whether SSRI exposure affects the maternal and infant gut microbiome. Sources were collected from PubMed, Web of Science, and Scopus databases, and an additional gray literature search was performed. Our search criteria returned only three sources, two rodent models and one human subjects research study. Results suggest that fluoxetine (SSRI) exposure may affect maternal gut microbiome dynamics during pregnancy and lactation. There were no available sources to describe the relationship between perinatal SSRI exposure and the infant gut microbiome. There is a significant gap in the literature regarding whether SSRI antidepressants affect the maternal and infant gut microbiome. Future studies are required to better understand how SSRI antidepressant exposure affects perinatal health.

Graduate Student Literature Review: Mammary gland development in dairy cattle - quantifying growth and development.

Mammary gland development research in dairy cattle has improved tremendously over the years, ranging from palpation to methods such as DNA/RNA sequencing, histological imaging, and medical imaging. Despite these advancements, there is limited evidence relating milk production with early mammary development due to incomplete and conflicting data. Further, data is typically not collected longitudinally in the same animals allowing for repeated measures analysis. Additional research is necessary to better understand development of the mammary gland and its direct relationship with subsequent ability to produce milk. As ultrasound has been shown to be a reliable method of visualizing mammary gland structure and parenchymal composition throughout the different stages of development in dairy cattle, it is possible that ultrasound technology can be used in future research to monitor and visualize longitudinal mammary development in dairy cattle noninvasively, and identify quantitative features indicative of milk production potential without culling. Identification of features indicative of higher milk production potential would not only aid in the selection of replacement heifers, but also has potential applications to human medicine with possible prediction of lactation potential in humans.

Intravenous infusion of 5-hydroxytryptophan to mid-lactation Holstein cows transiently affects milk production and circulating amino acid concentrations.

In dairy cows, the lactating mammary glands synthesize serotonin, which acts in an autocrine-paracrine manner in the glands and is secreted into the periphery. Serotonin signaling during lactation modulates nutrient metabolism in peripheral tissues such as adipose and liver. We hypothesized that the elevation of circulating serotonin during lactation would increase nutrient partitioning to the mammary glands, thereby promoting milk production. Our objective was to elevate circulating serotonin via intravenous infusion of the serotonin precursor 5-hydroxytryptophan (5-HTP) to determine its effects on mammary supply and extraction efficiency of AA, and milk components production. Twenty-two multiparous mid-lactation Holstein cows were intravenously infused with 5-HTP (1 mg/kg body weight) or saline, in a crossover design with two 21-d periods. Treatments were infused via jugular catheters for 1 h/d, on d 1 to 3, 8 to 10, and 15 to 17 of each period, to maintain consistent elevation of peripheral serotonin throughout the period. Milk and blood samples were collected in the last 96 h of each period. Whole-blood serotonin concentration was elevated above saline control for 96 h after the last 5-HTP infusion. Dry matter intake was decreased for cows receiving 5-HTP, and on average they lost body weight over the 21-d period, in contrast to saline cows who gained body weight. Milk production and milk protein yield were lower in cows receiving 5-HTP during the 3 infusion days, but both recovered to saline cow yields in the days after. Although milk fat yield exhibited a day-by-treatment interaction, no significant difference occurred on any given day. Milk urea nitrogen concentration was lower in 5-HTP cows on the days following the end of infusions, but not different from saline cows on infusion days. Meanwhile, plasma urea nitrogen was not affected by 5-HTP infusion. Circulating concentrations of AA were overall transiently decreased by 5-HTP, with concentrations mostly returning to baseline within 7 h after the end of 5-HTP infusion. Mammary extraction efficiency of AA was unaffected by 5-HTP infusion. Overall, both lactation performance and circulating AA were transiently reduced in cows infused with 5-HTP, despite sustained elevation of circulating serotonin concentration.

Apoptotic Marker Expression of Resected Lacrimal Gland Adenoid Cystic Carcinoma Tumor Margins After Intra-arterial Chemotherapy and Globe-Sparing Excision.

PURPOSE: Lacrimal gland adenoid cystic carcinoma (LGACC) is a rare orbital malignancy with devastating lethality. Neoadjuvant intra-arterial chemotherapy (IACC) has demonstrated cytoreductive effects on LGACC macroscopically, but limited studies have examined cellular and molecular determinants of the cytoreductive effect. This post hoc study assessed apoptotic marker expression on excised tumor specimens after neoadjuvant IACC and globe-sparing resection, emphasizing the examination of tumor margins. METHODS: This retrospective study identified LGACC specimens resected in a globe-sparing technique after neoadjuvant IACC by reviewing the Florida Lions Ocular Pathology database at Bascom Palmer Eye Institute. Histopathology slides of the specimens were re-examined to confirm the diagnosis and identify the tumor margin. Immunofluorescent staining was performed for apoptotic markers, including P53, cleaved caspase-3, cleaved PARP-1, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Positive expression was determined by comparison to the negative control. RESULTS: Tumor specimens from 5 patients met inclusion criteria. All 5 cases were positive at the center and the margin for TUNEL, p53, and cleaved caspase-3. One case did not show positive expression of cleaved PARP-1 at the margin but was positive for the other apoptotic markers. CONCLUSIONS: This post hoc study demonstrated positive staining for multiple apoptotic markers in post-IACC tumor specimens at the tumor center and margin. Apoptotic marker expression along the margins of post-treatment specimens is important, as it may offer surrogate information to speculate on the state of residual cancer cells adjacent to the excision margin inadvertently remaining in the orbit.

Longitudinal change in symptoms of depression, anxiety and post-traumatic stress disorder during the COVID-19 pandemic among Mexican college students.

Longitudinal studies suggest the psychological difficulties precipitated by the COVID-19 pandemic have gradually declined, but our understanding of the factors that predict change in mental health is limited. We evaluated the mental health of Mexican college students during the early stage of the pandemic and 4 months later, as well as predictors of change in students' mental health. Participants were 648 students (71% women, Mage = 21.46) from a private University in Northern Mexico who completed online surveys from May 2020 to September 2020. Students' self-reported levels of mental health symptoms (depression, anxiety and post-traumatic stress disorder) significantly decreased from May to September. Poor physical health, more COVID-related worry and higher initial levels of peer social support predicted less change in psychological symptoms. On the other hand, more hours of sleep per night and a pre-existing mental health diagnosis predicted steeper decreases in symptoms. Findings suggest reductions in mental health difficulties that are consistent with theoretical frameworks of resilience among Mexican college students. In addition, results underscore the interplay between physical, psychological and social functioning, and the need for continued monitoring of mental health and intervention efforts that address physical health, sleep and pandemic-related worry in University settings.

Syntheses and medicinal chemistry of spiro heterocyclic steroids.

There is compelling evidence that incorporating a heterocyclic moiety into a steroid can alter its pharmacological and pharmacokinetic properties, driving intense interest in the synthesis of such hybrids among research groups. In this review, we present an overview of recent synthetic methodologies, spanning the period from 2000 to 2023, for the preparation of spiro heterocyclic steroids. The compounds surveyed encompass four-, five-, six-, and seven-membered heterocycles appended to various positions of steroidal backbones, with spirocycles containing oxygen, nitrogen, and sulfur atoms being predominant. The outlined synthetic procedures emphasize the pivotal steps for constructing the heterocycles, often accompanied by a detailed account of the overall synthesis pathway. The review encompasses innovative compounds, including bis-steroids linked by a spiro heterocycle and steroids conjugated to heterocyclic moieties containing three or more (hetero)cycles. Moreover, many compounds are accompanied by data on their biological activities, such as antiproliferative, antimalarial, antimicrobial, antifungal, steroid antagonist, and enzyme inhibition, among others, aimed at furnishing pertinent insights for the future design of more potent and selective drugs.

The Serotonergic System and Bone Metabolism During Pregnancy and Lactation and the Implications of SSRI Use on the Maternal-Offspring Dyad.

Lactation is a physiological adaptation of the class Mammalia and is a product of over 200 million years of evolution. During lactation, the mammary gland orchestrates bone metabolism via serotonin signaling in order to provide sufficient calcium for the offspring in milk. The role of serotonin in bone remodeling was first discovered over two decades ago, and the interplay between serotonin, lactation, and bone metabolism has been explored in the years following. It is estimated that postpartum depression affects 10-15% of the population, and selective serotonin reuptake inhibitors (SSRI) are often used as the first-line treatment. Studies conducted in humans, nonhuman primates, sheep, and rodents have provided evidence that there are consequences on both parent and offspring when serotonin signaling is disrupted during the peripartal period; however, the long-term consequences of disruption of serotonin signaling via SSRIs during the peripartal period on the maternal and offspring skeleton are not fully known. This review will focus on the relationship between the mammary gland, serotonin, and bone remodeling during the peripartal period and the skeletal consequences of the dysregulation of the serotonergic system in both human and animal studies.

Longitudinal analysis of bovine mammary gland development.

Many studies on bovine mammary glands focus on one stage of development. Often missing in those studies are repeated measures of development from the same animals. As milk production is directly affected by amount of parenchymal tissue within the udder, understanding mammary gland growth along with visualization of its structures during development is essential. Therefore, analysis of ultrasound and histology data from the same animals would result in better understanding of mammary development over time. Thus, this research aimed to describe mammary gland development using non-invasive and invasive tools to delineate growth rate of glandular tissue responsible for potential future milk production. Mammary gland ultrasound images, biopsy samples, and blood samples were collected from 36 heifer dairy calves beginning at 10 weeks of age, and evaluated at 26, 39, and 52 weeks. Parenchyma was quantified at 10 weeks of age using ultrasound imaging and histological evaluation, and average echogenicity was utilized to quantify parenchyma at later stages of development. A significant negative correlation was detected between average echogenicity of parenchyma at 10 weeks and total adipose as a percent of histological whole tissue at 52 weeks. Additionally, a negative correlation between average daily gain at 10 and 26 weeks and maximum echogenicity at 52 weeks was present. These results suggest average daily gain and mammary gland development prior to 39 weeks of age is associated with development of the mammary gland after 39 weeks. These findings could be predictors of future milk production, however this must be further explored.