Candidate genes for litter size in Xinjiang sheep identified by Specific Locus Amplified Fragment (SLAF) sequencing

The aim of this study was to investigate the selection signatures at a genome-wide level in 'Pishan' sheep using Specific Locus Amplified Fragment (SLAF)-seq. Blood samples from 126 ewes were sequenced using SLAF tags, and the ovarian tissues from 8 ewes (Bashbay sheep, a single litter size group (SG group); 'Pishan' sheep, double litter size group (DG group)) were collected to detect expression levels by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Selection signature analysis was performed using global fixation index (Fst) and nucleotide diversity (π) ratio. A total of 1,192,168 high-quality SLAFs were identified. Notably, 2380 candidate regions under selection using two approaches were identified. A total of 2069 genes were identified, which were involved in dopaminergic synapses, thyroid hormone synthesis, ovarian steroidogenesis and thyroid hormone signalling pathways. Furthermore, Growth Differentiation Factor 9 (GDF9), Period Circadian Regulator 2 (PER2), Thyroid Stimulating Hormone Receptor (TSHR), and Nuclear Receptor Coactivator 1 (NCOA1) reside within these regions and pathways. The expression levels of GDF9 and PER2 genes in sheep tissue of the DG group were significantly higher than those in the SG group. These genes are interesting candidates for litter size and provide a starting point for further identification of conservation strategies for 'Pishan' sheep.

The Thyroid Hormone Axis and Female Reproduction

Thyroid function affects multiple sites of the female hypothalamic-pituitary gonadal (HPG) axis. Disruption of thyroid function has been linked to reproductive dysfunction in women and is associated with menstrual irregularity, infertility, poor pregnancy outcomes, and gynecological conditions such as premature ovarian insufficiency and polycystic ovarian syndrome. Thus, the complex molecular interplay between hormones involved in thyroid and reproductive functions is further compounded by the association of certain common autoimmune states with disorders of the thyroid and the HPG axes. Furthermore, in prepartum and intrapartum states, even relatively minor disruptions have been shown to adversely impact maternal and fetal outcomes, with some differences of opinion in the management of these conditions. In this review, we provide readers with a foundational understanding of the physiology and pathophysiology of thyroid hormone interactions with the female HPG axis. We also share clinical insights into the management of thyroid dysfunction in reproductive-aged women.

Radioactive Iodine-induced hypothyroidism interferes with the maturation of reproductive organs during puberty in immature female rats

Animal and human studies suggest that thyroid hormone may have critical roles in the development of the ovary. For example, thyroid deficiency disrupts the ovarian microarchitecture and menstrual cycle in neonate and adult women, respectively. Therefore, it is conceivable that thyroid deficiency might disrupt sexual maturation during the peri-pubertal period. To investigate the impact of radioactive iodine-induced thyroid deficiency on reproductive organs throughout puberty, immature female rats were given water containing radioactive iodine (0.37 MBq/g body weight) twice, on postnatal days 22 and 29. Radioactive iodine-induced hypothyroidism was revealed by low free thyroxin levels. Thyroid deficiency delayed the onset of vaginal opening, reduced ovarian weight and the number of medium-sized follicles and led to elongated uteri. However, there was no effect on the estrous cycle or absolute uterus weight. We conclude that radioactive iodine-induced thyroid deficiency delays sexual maturation and alters normal ovarian growth in peri-pubertal rats.

Impact of photoperiod on uterine redox/inflammatory and metabolic status of golden hamster, Mesocricetus auratus

Photoperiod modulates reproductive physiology at multiple levels in seasonally breeding animals. Golden hamsters are long-day breeders that diminish their fertility during the short days. Photoperiod is known to regulate hormonal milieu and uterus is a hormone-sensitive dynamic tissue. However, there is lack of molecular insight regarding the impact of photoperiod on uterine physiology with respect to redox and metabolic status in Mesocricetus auratus. We evaluated the impact of photoperiod on circulatory hormonal parameters (triiodothyronine [T3], thyroxin [T4], estradiol [E2], progesterone [P4], melatonin, and insulin), their receptor expressions and key markers associated with redox (SIRT-1/FOXO-1), inflammatory (NFĸB/COX-2) and metabolic (IR/GLUT4) status in uterus. Adult female golden hamsters were exposed to different photoperiodic regimes, that is, short photoperiod (SP; 8L:16D) and long photoperiod (LP; 16L:8D) for 12 weeks. SP drastically decreased peripheral hormone profiles (T3, T4, E2, and P4) and compromised uterine histoarchitecture when compared with LP-exposed hamsters. Further, SP markedly decreased thyroid hormone receptor-α (TRα), insulin receptor, and glucose uptake transporter-4 (GLUT-4) expressions in uterus. We noted enhanced uterine oxidative (increased MDA and decreased SOD/CAT levels), SIRT-1/FOXO-1 expression and inflammatory (NFĸB/COX-2) load in SP condition. Further, elevated levels of circulatory insulin, melatonin, and its receptor (MT-1) expression in uterus was noted under SP condition. Thus, we may suggest that photoperiod might regulate uterine seasonality through modulation of local hormonal and redox/metabolic homeostasis thereby may restrict offspring bearing capacity under short days.

Hypothyroidism is prevalent among adult women with chronic lower urinary tract symptoms

OBJECTIVE

To define the prevalence of hypothyroidism in women with chronic lower urinary tract symptoms (LUTS) and to compare the severity of each symptom between patients with hypothyroidism and controls.

SUBJECTS AND METHODS

In this prospective observational study, we screened all adult women who came to the urology clinic between March 2017 and September 2020, and enrolled patients with chronic LUTS in the study. We assessed thyroid function. We evaluated the severity of voiding and storage urinary symptoms by the International Prostate Symptom Score. We also assessed the severity of urge urinary incontinence (UUI) and stress urinary incontinence (SUI). For between-group analysis, we selected age-matched cases and controls and compared them regarding the distribution and severity of urinary symptoms.

RESULTS

Seven hundred and twenty-five women with a mean age of 51.7 ± 14.0 years were included in the final analysis. Two hundred fifty-eight patients (35.6%) had hypothyroidism. Age-matched case and control groups consisting of 210 patients each were selected. There was no significant difference in the severity and distribution of voiding LUTS and UUI between the study groups (P values >0.05). The severity of storage symptoms was lower in patients with hypothyroidism (P = 0.04). Sixty-seven patients with hypothyroidism (31.9%) had SUI, which was significantly higher than controls (23.3%) (P = 0.03).

CONCLUSION

More than one-third of women with chronic LUTS have hypothyroidism which is much more frequent than in the general population. We also suggest a possible relationship between hypothyroidism and the severity of SUI and an inverse relationship between hypothyroidism and storage symptoms.

Congenital Hypothyroidism Can Dictate the Mode of Delivery and Intra-Labor Medication Usage

Background: Pregnancy and parturition reflect the complex interaction between physiological conditions of the mother and her offspring, and fetal health characteristics may affect maternal health throughout pregnancy and delivery. We aimed to investigate the characteristics of the mother-infant dyad of term infants detected as having congenital hypothyroidism (CH). Methods: A retrospective cohort study of 108,717 term infants delivered liveborn at Lis Maternity and Women's Hospital between 2010 and 2017. Infants were detected by the National Newborn Screening Program as having CH (131, 0.12%). Three years of surveillance in the Pediatric Endocrine Clinic revealed that 65 infants had transient CH and 66 had permanent CH. Data on maternal, pregnancy, delivery, and perinatal characteristics of the mother-infant dyads were retrieved from the hospital's electronic database. Results: Mode of delivery differed: a higher proportion of deliveries of CH infants required vacuum assistance, and more infants with CH were born through a cesarean section compared with the general population (p < 0.001). Medication during labor also differed, with higher rates of oxytocin (p < 0.001) and antibiotics (p = 0.008) administered to mothers of CH infants. A multivariate logistic regression model revealed an increased demand for oxytocin administration during the labor of a CH infant in a hypothyroidism severity-dependent manner, expressed as a threefold risk associated with permanent but not transient CH. Conclusions: Our findings of increased utilization of medical interventions during the labor and delivery of CH infants suggest that the prenatal fetal thyroid function may affect the development and progress of labor and delivery, in response to oxytocin.

Fetal Hypothyroidism Impairs Aortic Vasorelaxation Responses in Adulthood: Involvement of Hydrogen Sulfide and Nitric Oxide Cross talk

ABSTRACT

Thyroid hormones have a wide range of effects on growth, differentiation, evolution, metabolism, and physiological function of all tissues, including the vascular bed. In this study, the effect of fetal hypothyroidism on impairment of aortic vasorelaxation responses in adulthood was investigated with emphasis on possible involvement of hydrogen sulfide (H2S)/nitric oxide interaction. Two groups of female rats were selected. After mating and observation of vaginal plaque, one group received propylthiouracil (200 ppm in drinking water) until the end of pregnancy and another group had no propylthiouracil treatment during the fetal period. In adult rats, aortic relaxation responses to l-arginine and GYY4137 were assessed in the presence or absence of Nω-nitro-L-arginine methyl ester hydrochloride and dl-propargylglycine in addition to the biochemical measurement of thyroid hormones and some related factors. Obtained findings showed a lower vasorelaxation response for GYY4137 and l-arginine in the fetal hypothyroidism group, and preincubation with Nω-nitro-L-arginine methyl ester hydrochloride or dl-propargylglycine did not significantly aggravate this weakened relaxation response. In addition, aortic levels of sirtuin 3, endothelial nitric oxide synthase, cystathionine gamma-lyase, and H2S were significantly lower in the fetal hypothyroidism group. Meanwhile, no significant changes were obtained regarding serum levels of thyroid hormones including free triiodothyronine;, total triiodothyronine, free thyroxine, total thyroxine, and thyroid-stimulating hormone in adult rats. It can be concluded that hypothyroidism in the fetal period has inappropriate effects on the differentiation and development of vascular bed with subsequent functional abnormality that persists into adulthood, and part of this vascular abnormality is mediated through weakened interaction and/or cross talk between H2S and nitric oxide.

Using High-Density SNP Array to Reveal Selection Signatures Related to Prolificacy in Chinese and Kazakhstan Sheep Breeds

Selection signature provides an efficient tool to explore genes related to traits of interest. In this study, 176 ewes from one Chinese uniparous breed and three Kazakhstan multiparous breeds are genotyped using Affymetrix 600K HD single nucleotide polymorphism (SNP) arrays, F-statistics (Fst), and a Cross Population Extend Haplotype Homozygosity Test (XPEHH). These are conducted to identify genomic regions that might be under selection in three population pairs comprised the one multiparous breed and the uniparous breed. A total of 177 and 3072 common selective signatures were identified by Fst and XPEHH test, respectively. Nearly half of the common signatures detected by Fst were also captured by XPEHH test. In addition, 1337 positive and 1735 common negative signatures were observed by XPEHH in three Kazakhstan multiparous breeds. In total, 242 and 798 genes were identified in selective regions and positive selective regions identified by Fst and XPEHH, respectively. These genes were further clustered in 50 gene ontology (GO) functional terms and 66 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in enrichment analysis. The GO terms and pathways were relevant with reproductive processes, e.g., oxytocin signaling pathway, thyroid hormone synthesis and GnRH signaling pathway, vascular smooth muscle contraction and lipid metabolism (alpha-Linolenic acid metabolism and Linoleic acid metabolism), etc. Based on the findings, six potential candidate genes ESR1, OXTR, MAPK1, RYR1, PDIA4, and CYP19A1, under positive selection related to characteristics of multiparous sheep breeds were revealed. Our results improve our understanding of the mechanisms of selection that underlies the prolificacy trait in sheep, and provide essential references for future sheep breeding.

Changes in nitric oxide synthase levels are associated with impaired cardiac function and tolerance to ischemia-reperfusion injury in male rats with transient congenital hypothyroidism

Transient congenital hypothyroidism (TCH) has long-lasting consequences on the cardiovascular system during adulthood. The aim of this study was to determine whether nitric oxide (NO) and NO-producing enzymes are involved in impaired cardiac function as well as decreased tolerance to ischemia-reperfusion (IR) injury in adult male rats with TCH. Pregnant rats were divided into control and hypothyroid groups. Male offspring rats were categorized in control and hypothyroid (TCH) groups at week 16. Levels of NOx (nitrate+nitrite) and neuronal NOS (nNOS), inducible NOS (iNOS), and endothelial NOS (eNOS) were measured in hearts of rats and isolated perfused hearts from both groups were subjected to IR. Levels of NOx and NOSs were also measured in both groups after ischemia. Compared with controls, heart NOx levels were higher at baseline (48.0 ± 4.9 vs. 35.0 ± 2.6 μmol/L; P = 0.034) and following IR (103.6 ± 4.2 vs. 70.2 ± 2.7 μmol/L; P < 0.001) in rat with TCH. At baseline, compared with controls, heart iNOS and nNOS levels were significantly higher in rats with TCH (6.12 ± 0.34 vs. 4.78 ± 0.27 ng/mg protein; P = 0.008 for iNOS and 4.87 ± 0.28 vs. 3.55 ± 0.23 ng/mg protein; P = 0.003 for nNOS). Following IR, in rats with TCH, heart iNOS levels increased (11.75 ± 2.02 vs. 6.12 ± 0.34, ng/mg protein; P = 0.015) whereas nNOS level decreased (4.10 ± 0.25 vs. 4.87 ± 0.28 ng/mg protein; P = 0.063). Adverse effects of TCH on cardiac function are associated with increased ratio of iNOS/eNOS; in addition, increased heart nNOS levels are involved in impaired cardiac function while its decrease is associated with decreased tolerance to IR injury.

Hypothyroidism induces uterine hyperplasia and inflammation related to sex hormone receptors expression in virgin rabbits

AIMS

In women, uterine alterations have been associated with sex steroid hormones. Sex hormones regulate the expression of thyroid hormone receptors (TRs) in the uterus, but an inverse link is unknown. We analyzed the impact of hypothyroidism on histological characteristics, vascular endothelial growth factor (VEGF-A), progesterone receptors (PR), estrogen receptors (ER), thyroid hormone receptors (TRs), perilipin (PLIN-A), and lipid content in the uterus of virgin rabbits.

MAIN METHODS

Twelve Chinchilla-breed adult female rabbits were grouped into control (n = 6) and hypothyroid (n = 6; 0.02% of methimazole for 30 days). The thickness of endometrium and myometrium, number of uterine glands, and infiltration of immune cells were analyzed. The expression of VEGF-A, PR, ERα, and PLIN-A was determined by RT-PCR and western blot. The uterine content of triglycerides (TAG), total cholesterol (TC), and malondialdehyde (MDA) was quantified.

KEY FINDINGS

Hypothyroidism promoted uterine hyperplasia and a high infiltration of immune cells into the endometrium, including macrophages CD163+. It also increased the expression of VEGF-A, TRA, and ERα-66 but reduced that of PR and ERα-46. The uterine content of PLIN-A, TAG, and TC was reduced, but that of MDA was augmented in hypothyroid rabbits.

SIGNIFICANCE

Our results suggest that uterine hyperplasia and inflammation promoted by hypothyroidism should be related to changes in the VEGF-A, PR, ER, and TRs expression, as well as to modifications in the PLIN-A expression, lipid content, and oxidative status. These results suggest that hypothyroidism should affect the fertility of females.