CRISPRi-Mediated Treatment of Dominant Rhodopsin-Associated Retinitis Pigmentosa

Rhodopsin (RHO) mutations such as Pro23His are the leading cause of dominantly inherited retinitis pigmentosa in North America. As with other dominant retinal dystrophies, these mutations lead to production of a toxic protein product, and treatment will require knockdown of the mutant allele. The purpose of this study was to develop a CRISPR-Cas9-mediated transcriptional repression strategy using catalytically inactive Staphylococcus aureus Cas9 (dCas9) fused to the Krüppel-associated box (KRAB) transcriptional repressor domain. Using a reporter construct carrying green fluorescent protein (GFP) cloned downstream of the RHO promoter fragment (nucleotides -1403 to +73), we demonstrate a ∼74-84% reduction in RHO promoter activity in RHOpCRISPRi-treated versus plasmid-only controls. After subretinal transduction of human retinal explants and transgenic Pro23His mutant pigs, significant knockdown of rhodopsin protein was achieved. Suppression of mutant transgene in vivo was associated with a reduction in endoplasmic reticulum (ER) stress and apoptosis markers and preservation of photoreceptor cell layer thickness.

MicroRNA21 inhibition affects porcine oocyte maturation and alters protein expression critical for metabolic pathway function

MicroRNA21 (MIR21) abundance in porcine oocytes and cumulus cells increases during in vitro maturation. The mechanism by which MIR21 regulates oocyte maturation and the effect on the developmental competence of subsequent embryos remains unclear. The objective of this study was to assess the function of MIR21 during porcine oocyte maturation and its effect on embryonic development. Treatment with peptide nucleic acid MIR21 inhibitor (MIR21-PNA), designed to specifically bind to and prevent MIR21 activity during in vitro oocyte maturation, decreased cumulus cell expansion, and the oocyte ability to achieve metaphase II maturation stage when compared to control groups. Following parthenogenetic activation, the cleavage rate at 48 h in the MIR21-PNA group was decreased (p ≤ 0.03) relative to the control groups. Additionally, liquid chromatography-mass spectrometry (LC-MS/MS) of oocyte and cumulus cell total protein following MIR21-PNA treatment during in vitro maturation identified changes in signaling pathways with primary involvement of glucose metabolism (GM) pathways. Furthermore, there was no difference (p = 0.21) in oocyte maturation of control and MIR21-PNA treated oocytes when cultured in pyruvate lacking medium. Finally, MIR21-PNA treatment decreased (p = 0.04) glutathione and increased (p = 0.07) reactive oxygen species production in the oocyte. These data suggest that MIR21 influences porcine oocyte maturation by regulating GM pathways in the cumulus-oocyte complex.

Porcine endometrial heat shock proteins are differentially influenced by pregnancy status, heat stress, and altrenogest supplementation during the peri-implantation period

Heat stress (HS) deleteriously affects multiple components of porcine reproduction and is causal to seasonal infertility. Environment-induced hyperthermia causes a HS response (HSR) typically characterized by increased abundance of intracellular heat shock proteins (HSP). Gilts exposed to HS during the peri-implantation period have compromised embryo survival, however if (or how) HS disrupts the porcine endometrium is not understood. Study objectives were to evaluate the endometrial HSP abundance in response to HS during this period and assess the effect of oral progestin (altrenogest; ALT) supplementation. Postpubertal gilts (n = 42) were artificially inseminated during behavioral estrus (n = 28) or were kept cyclic (n = 14), and randomly assigned to thermal neutral (TN; 21 ± 1 °C) or diurnal HS (35 ± 1 °C for 12 h/31.6 ± 1 °C for 12 h) conditions from day 3 to 12 postestrus (dpe). Seven of the inseminated gilts from each thermal treatment group received ALT (15 mg/d) during this period. Using quantitative PCR, transcript abundance of HSP family A (Hsp70) member 1A (HSPA1A, P = 0.001) and member 6 (HSPA6, P < 0.001), and HSP family B (small) member 8 (HSB8, P = 0.001) were increased while HSP family D (Hsp60) member 1 (HSPD1, P = 0.01) was decreased in the endometrium of pregnant gilts compared to the cyclic gilts. Protein abundance of HSPA1A decreased (P = 0.03) in pregnant gilt endometrium due to HS, while HSP family B (small) member 1 (HSPB1) increased (P = 0.01) due to HS. Oral ALT supplementation during HS reduced the transcript abundance of HSP90α family class B member 1 (HSP90AB1, P = 0.04); but HS increased HSP90AB1 (P = 0.001), HSPA1A (P = 0.02), and HSPA6 (P = 0.04) transcript abundance irrespective of ALT. ALT supplementation decreased HSP90α family class A member 1 (HSP90AA1, P = 0.001) protein abundance, irrespective of thermal environment, whereas ALT only decreased HSPA6 (P = 0.02) protein abundance in TN gilts. These results indicate a notable shift of HSP in the porcine endometrium during the peri-implantation period in response to pregnancy status and heat stress.

Circulating biomarkers associated with pelvic organ prolapse risk in late gestation sows

Sow mortality, as the result of pelvic organ prolapse (POP), has been increasing in the last decade in the U.S. swine industry. The objective of this study was to identify potential biological markers associated with risk of POP in sows. We hypothesized that sows differing in perineal score (PS) from PS1–PS3 (PS1—a presumed low POP risk; PS2—a presumed moderate POP risk; and PS3—a presumed high POP risk) would differ in circulatory biomarkers of inflammation and hormonal profiles. On gestation week 15, 2,864 individual sows were assigned a PS, and subsequently, 1.0%, 2.7%, and 23.4% of PS1, PS2, or PS3 sows, respectively, experienced POP. During PS assignment at days 107–116 of gestation, blood samples were collected from sows on two farms of similar genetics, feed sources, and health status. Whole blood was subjected to complete blood count (CBC) analysis (n = 212) and steroid hormones were measured in serum from a subset (n = 110) of animals assigned PS3 parity matched to PS1. Lipopolysaccharide-binding protein (LBP), tumor necrosis factor-alpha (TNF-α), haptoglobin, C-reactive protein (CRP), and creatine kinase (CK) levels were also evaluated. Complete blood count analysis revealed decreased (P ≤ 0.05) mean platelet volume (3.9%), lymphocytes (6.5%), and monocytes (7.5%) in PS3 compared to PS1 sows. Increased (P ≤ 0.02) abundance of androstenedione (13.4%), androsterone (18.2%), estrone (24.8%), and 17β-estradiol (26.2%) was observed in PS3 compared to PS1 sows. Additionally, a 25.8% increase (P = 0.04) in LBP in PS3 compared to PS1 sows was observed. Many dynamic physiological changes occur in sows during late gestation as they approach farrowing. The data presented herein demonstrate that distinct differences in concentrations of circulating biomarkers exist between late gestation sows at high or low risk for POP and may serve as a useful tool for understanding the etiology of POP and evaluation of mitigation strategies.

Altered eutopic endometrial T-regulatory and T-helper 17 lymphocyte ratio in women with unexplained subfertility

PROBLEM

Perturbations in T-helper lymphocyte profiles have previously been associated with endometriosis related subfertility and conception failure. Hence a retrospective in vitro study was conducted to evaluate the relationship between T-regulatory (Treg) and T-helper 17 (Th17) lymphocytes in the eutopic endometrium of women with unexplained subfertility and correlate these profiles to their conception status.

METHOD OF STUDY

Eutopic endometrial biopsies were collected during the mid-secretory phase of the menstrual cycle, from women with unexplained subfertility. These samples were evaluated immunohistochemically for Treg and Th17 lymphocytes as well as the related proinflammatory cytokine, Interleukin-17 (IL-17). These eutopic endometrial T lymphocyte subpopulations were compared to the patients' conception status in subsequent cycles.

RESULTS

Though Treg cells were not indicative of conception success in subsequent cycles, patients who maintained their subfertile (no conception) status were observed to have a higher Th17 cell count in their eutopic endometrium. The ratio of Treg:Th17 cell counts was significantly correlated to patient conception status as well. These trends stayed consistent irrespective of concurrent endometriosis.

CONCLUSION

Patients with a high proinflammatory Th17 lymphocyte profile and low Treg:Th17 ratio in their eutopic endometrium during the secretory phase of their menstrual cycle are more likely to not conceive in subsequent cycles.

Effect of ARTEMIS (DCLRE1C) deficiency and microinjection timing on editing efficiency during somatic cell nuclear transfer and in vitro fertilization using the CRISPR/Cas9 system

The ability to efficiently introduce site-specific genetic modifications to the mammalian genome has been dramatically improved with the use of the CRISPR/Cas9 system. CRISPR/Cas9 is a powerful tool used to generate genetic modifications by causing double-strand breaks (DSBs) in DNA. Artemis (ART; also known as DCLRE1C), is a nuclear protein and is essential for DSB end joining in DNA repair via the canonical non-homologous end joining (c-NHEJ) pathway. In this work, we tested whether ART deficiency affects DNA repair following CRISPR/Cas9 induced DSBs in somatic cells. We also demonstrated the effect of microinjection timing on embryo developmental ability and gene targeting efficiency of CRISPR/Cas9 system to disrupt the interleukin 2 receptor subunit gamma (IL2RG) locus using porcine in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) derived embryos. In comparison to non-injected controls, CRISPR/Cas9 injection of IVF derived zygotes at 4 h and 8 h after fertilization did not impact cleavage and blastocyst rate. Gene modification rate was observed to be higher, 53.3% (9/16) in blastocysts injected 4 h post-fertilization as compared to 11.1% (1/9) in blastocysts injected 8 h post-fertilization. Microinjection 8 h after chemical activation of SCNT derived embryos decreased blastocyst development rate compared to non-injected controls but showed a higher gene modification efficiency of 66.7% as compared to 25% in the 4 h post-activation injection group. Furthermore, we observed that male ART^-/- and ART^+/- porcine fetal fibroblast (pFF) cells showed lower modification rates (2.5% and 1.9%, respectively) as compared to the ART intact cell line (8.3%). Interestingly, the female ART^-/- and ART^+/- pFF cells had modification rates (4.2% and 10.1%, respectively) similar to those seen in the ART intact cells. This study demonstrates the complex effect of various parameters such as microinjection timing and ART deficiency on gene editing efficiency in in vitro derived porcine embryos.

Characterization of the effects of heat stress on autophagy induction in the pig oocyte

BACKGROUND

Heat stress (HS) occurs when body heat accumulation exceeds heat dissipation and is associated with swine seasonal infertility. HS contributes to compromised oocyte integrity and reduced embryo development. Autophagy is a potential mechanism for the oocyte to mitigate the detrimental effects of HS by recycling damaged cellular components.

METHODS

To characterize the effect of HS on autophagy in oocyte maturation, we utilized an in vitro maturation (IVM) system where oocytes underwent thermal neutral (TN) conditions throughout the entire maturation period (TN/TN), HS conditions during the first half of IVM (HS/TN), or HS conditions during the second half of IVM (TN/HS).

RESULTS

To determine the effect of HS on autophagy induction within the oocyte, we compared the relative abundance and localization of autophagy-related proteins. Heat stress treatment affected the abundance of two well described markers of autophagy induction: autophagy related gene 12 (ATG12) in complex with ATG5 and the cleaved form of microtubule-associated protein 1 light chain 3 beta (LC3B-II). The HS/TN IVM treatment increased the abundance of the ATG12-ATG5 complex and exacerbated the loss of LC3B-II in oocytes. The B-cell lymphoma 2 like 1 protein (BCL2L1) can inhibit autophagy or apoptosis through its interaction with either beclin1 (BECN1) or BCL2 associated X, apoptosis regulator (BAX), respectively. We detected colocalization of BCL2L1 with BAX but not BCL2L1 with BECN1, suggesting that apoptosis is inhibited under the HS/TN treatment but not autophagy. Interestingly, low doses of the autophagy inducer, rapamycin, increased oocyte maturation.

CONCLUSIONS

Our results here suggest that HS increases autophagy induction in the oocyte during IVM, and that artificial induction of autophagy increases the maturation rate of oocytes during IVM. These data support autophagy as a potential mechanism activated in the oocyte during HS to recycle damaged cellular components and maintain developmental competence.

83 MicroRNA574-3p Influences Porcine Oocyte Maturation and Regulates Abundance of Proteins Critical to Early Embryo Development

MicroRNA are small non-coding RNA involved in post-transcriptional gene regulation impacting oocyte maturation and embryo development. MIR574-3p abundance decreases during oocyte in vitro maturation (IVM) and blastocyst development. The study objective was to evaluate the role of MIR574-3p during porcine oocyte maturation and early embryo development. To assess the function of MIR574-3p during these processes, denuded GV stage oocytes injected with MIR574-3p mimic (MIR574-3p-M), MIR574-3p inhibitor (MIR574-3p-I) or negative control oligo (NC) underwent IVM for 42 hours. The number of MII arrested oocytes was decreased (P = 0.06) in the MIR574-3p-M group (67.7 ± 1.4%) as compared to the NC group (76.1 ± 1.3%), whereas maturation was not affected by MIR574-3p-I (75.6 ± 1.5%) as compared to the NC group (73.1 ± 3.6%). MII arrested oocytes were parthenogenetically activated and cultured for 7 days. Neither mimic nor inhibitor affected the cleavage or blastocyst rate. Using LC-MS/MS we evaluated changes in global protein abundance in injected oocytes after 42 hours of IVM. We identified 971 proteins in MIR574-3p-M injected oocytes, of which 57 were differentially abundant as compared to the control group. In MIR574-3p-I injected oocytes, 1007 proteins were identified, of which 107 were differentially abundant as compared to the control group. Overall, MIR574-3p-M upregulated proteins critical to membrane binding mediating sperm receptors on the zona pellucida, while it downregulated intranuclear activity such as nucleotide biosynthesis, mitotic spindle assembly and orientation; whereas MIR574-3p-I induced upregulation of proteins involved in the processes between and including protein biosynthesis and metabolism, while downregulating proteins critical to ATP, RNA, DNA and protein binding. These data suggest artificially increasing MIR574-3p abundance during IVM alters the oocyte proteome and influences meiotic progression to MII. Project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2017-67015-26459 from the USDA National Institute of Food and Agriculture.

117 Improved Growth Performance in the F1 Heterozygous Generation of an SSTR2 Knockout Model in Swine

Targeted genetic alteration provides opportunities for rapid genetic improvement in resilience, welfare and production traits. Somatostatin (SST) acts via negative feedback to regulate growth hormone (GH) activity by antagonizing GH releasing hormone via SST receptors (SSTR) located in the anterior pituitary. Our objective was to reduce the negative effect of SST in the anterior pituitary on protein accretion by reducing the number of functional copies of SSTR2 using the CRISPR/Cas9 system. We hypothesized that a reduction or elimination of SSTR2 would lead to improved growth performance. To test this hypothesis, three commercial gilts were bred with semen from a founder boar in a compound heterozygous state at the SSTR2 locus with a 1bp deletion in one allele resulting in a premature stop codon and a 3bp deletion in the other allele resulting in the loss of a single amino acid predicted to remain functional after translation. Three litters of F1 offspring were produced (n = 46) and all piglets were confirmed to be heterozygous at the SSTR2 locus with one wild type allele and the other possessing either the 1bp deletion (n = 22) or the 3bp (n = 2 4) deletion. No differences (P &gt; 0.43; n=46) in body weight (1.27±0.03 kg) across comparisons were observed at birth. At weaning (n = 36), males (6.19±0.20 kg) were heavier (P = 0.007) than females (5.41±0.19 kg), and piglets possessing a 1bp deletion (6.00±0.20 kg) were numerically heavier (P = 0.14) than 3bp deletion pigs (5.59±0.18 kg). This observation was more pronounced in males at weaning, where the males with the 1bp deletion were 13% heavier (P = 0.058) than those with the 3bp deletion. These data suggest that altering SSTR2 may be a viable genetic advancement strategy to improve growth performance in pigs. This project was supported by the Lloyd L. Anderson Professorship in Physiology at Iowa State University.

79 Direct and Indirect Effects of Heat Stress on the Hepatic and Ovarian Proteome in Gilts

Seasonal infertility (SI) caused by heat stress (HS) impacts the US swine industry by reducing litter size, farrowing rates, and production efficiency. Identifying the biological underpinnings of SI is a foundational step towards developing mitigation strategies to reduce the nearly $1 billion annual revenue losses to the swine industry. The study objective was to investigate the direct and indirect effects of HS via HS conditioned serum infusion in swine. We hypothesized gilts housed in thermoneutral (TN) conditions receiving gradual infusions of serum obtained from HS gilts would experience altered endocrine and metabolic function compared to gilts receiving serum from TN gilts. Prepubertal gilts (n = 18) were assigned to donor or recipient groups and donors were allocated to TN or HS environments. Blood was collected from HS donors and TN donors exposed to 24-hours of HS or TN conditions, respectively. Serum was infused into recipients housed in TN conditions via indwelling jugular catheters. Over a 24-hour period approximately 20% of the estimated recipient gilt serum volume from donors (pooled by treatment) was infused into recipients. After infusions were completed, gilts were euthanized and tissues collected. Increased rectal temperatures were observed in HS recipients compared to TN recipients (P ≤ 0.05). Protein extracts from liver and ovary underwent proteomic analysis via liquid-chromatography with tandem mass-spectrometry (LC-MS/MS) to assess protein abundance. In the liver and ovary, we identified 135 and 264 proteins, respectively, that were differentially abundant between TN and HS recipients (P &lt; 0.10). Gene Ontology enrichment analysis identified alterations to pathways involved in hormone regulation, immune response, and apoptosis. Collectively, these data demonstrate gilts receiving HS serum experienced altered endocrine and metabolic function compared to gilts receiving TN serum. This project was supported in part by the Iowa Pork Producers Association. USDA is an equal opportunity provider and employer.

Inhibition of germinal vesicle breakdown using IBMX increases microRNA-21 in the porcine oocyte

BACKGROUND

Germinal vesicle breakdown (GVBD) occurs during oocyte meiotic maturation, a period when transcriptional processes are virtually inactive. Thus, the maturing oocyte is reliant on processes such as post-transcriptional gene regulation (PTGR) to regulate the mRNA and protein repertoire. MicroRNA (miRNA) are a class of functional small RNA that target mRNA to affect their abundance and translational efficiency. Of particular importance is miRNA-21 (MIR21) due to its role in regulating programmed cell death 4 (PDCD4). The objective of this study was to characterize the abundance and regulation of MIR21 in relation to GVBD.

METHODS

Oocytes were collected from aspirated porcine tertiary follicles. Relative abundance of mature MIR21 was quantified at 0, 8, 16, 24, 32, and 42 h of in vitro (IVM) with or without treatment with 3-isobutyl-1-methylxanthine (IBMX).

RESULTS

IBMX increased abundance of MIR21 at 24 h approximately 30-fold compared to control oocytes (P < 0.05), and the induced increase in MIR21 abundance at 24 h was concomitant with premature depletion of PDCD4 protein abundance. To characterize the effect of artificially increasing MIR21 on oocyte competence without inhibiting GVBD, a MIR21 mimic, scrambled microRNA negative control, or nuclease free water was micro-injected into denuded oocytes at 21 h of IVM. The maturation rate of oocytes injected with synthetic MIR21 (63.0 ± 7.5%) was higher than oocytes injected with negative controls (P < 0.05).

CONCLUSIONS

Inhibition of nuclear meiotic maturation via IBMX significantly increased MIR21 and decreased its target, PDCD4. Injection of a MIR21 mimic increased oocyte maturation rate. Our results indicate MIR21 is active and important during meiotic maturation of the oocyte.

Differentiating between the effects of heat stress and lipopolysaccharide on the porcine ovarian heat shock protein response1

Heat stress (HS) negatively affects both human and farm-animal health and undermines efficiency in a variety of economically important agricultural variables, including reproduction. HS impairs the intestinal barrier, allowing for translocation of the resident microflora and endotoxins, such as lipopolysaccharide (LPS), from the gastrointestinal lumen into systemic circulation. While much is known about the cellular function of heat shock proteins (HSPs) in most tissues, the in vivo ovarian HSP response to stressful stimuli remains ill-defined. The purpose of this study was to compare the effects of HS or LPS on ovarian HSP expression in pigs. We hypothesized that ovarian HSPs are responsive to both HS and LPS. Altrenogest (15 mg/d) was administered per os for estrus synchronization (14 d) prior to treatment and three animal paradigms were used: (i) gilts were exposed to cyclical HS (31 ± 1.4 °C) or thermoneutral (TN; 20 ± 0.5 °C) conditions immediately following altrenogest withdrawal for 5 d during follicular development; (ii) gilts were subjected to repeated (4×/d) saline (CON) or LPS (0.1 μg/kg BW) i.v. infusion immediately following altrenogest withdrawal for 5 d; and (iii) gilts were subjected to TN (20 ± 1 °C) or cyclical HS (31 to 35 °C) conditions 2 d post estrus (dpe) until 12 dpe during the luteal phase. While no differences were detected for transcript abundances of the assessed ovarian HSP, the protein abundance of specific HSP was influenced by stressors during the follicular and luteal phases. HS during the follicular phase tended (P < 0.1) to increase ovarian protein abundance of HSP90AA1 and HSPA1A, and increased (P ≤ 0.05) HSF1, HSPD1, and HSPB1 compared with TN controls, while HS decreased HSP90AB1 (P = 0.01). Exposure to LPS increased (P < 0.05) HSP90AA1 and HSPA1A and tended (P < 0.1) to increase HSF1 and HSPB1 compared with CON gilts, while HSP90AB1 and HSPD1 were not affected by LPS. HS during the luteal phase increased (P < 0.05) abundance of HSPB1 in corpora lutea (CL), decreased (P < 0.05) CL HSP90AB1, but did not impact HSF1, HSPD1, HSP90AA1, or HSPA1A abundance. Thus, these data support that HS and LPS similarly regulate expression of specific ovarian HSP, which suggest that HS effects on the ovary are in part mediated by LPS.

Anti-Müllerian hormone inhibits luteinizing hormone-induced androstenedione synthesis in porcine theca cells

AMH (Anti-Müllerian Hormone) is involved in the regulation of follicle growth initiation and inhibits FSH-induced aromatase expression and estrogen production in granulosa cells. However, the function of AMH in steroidogenesis by theca cells remains unclear. The aim of this study is to investigate the role of AMH as a regulator of the basal and stimulated steroid production by pig granulosa cells (pGCs) and theca cells (pTCs). PGCs and pTCs were incubated with hormones AMH, LH (luteinizing hormone), FSH (follicle stimulating hormone), individually or in combination. The expression of CYP19A1, HSD3B1, CYP11A1, LHCGR, and CYP17A1 mRNA were evaluated by quantitative reverse transcriptase PCR. In pGCs, 10 ng/mL AMH significantly decreased the FSH-stimulated effect on FSHR and CYP19A1 expression and estradiol production. In pTCs, LH treatment significantly increased the expression of HSD3B1, CYP11A1, LHCGR, and androstenedione or progesterone production (P < 0.05). Additionally, 10 ng/mL AMH also significantly decreased the LH-stimulated effects on the expression of HSD3B1, CYP11A1, CYP17A1, LHCGR and androstenedione production. Transfection with siAMHR2-I abolished the suppressive effects of AMH on LH-induced HSD3B1 expression and androstenedione production. Taken together, these results demonstrate that AMH is involved in FSH induced estradiol production in pGCs and LH induced androstenedione production in pTCs by regulating the steroidogenesis pathway.

208 Molecular mechanisms through which heat stress compromises reproduction in pigs

Seasonal variations in environmental temperatures impose added stress on domestic species bred for economically important production traits. These heat-mediated stressors vary on a seasonal, daily, or spatial scale, and negatively impact behavior and reduce feed intake and growth rate, which inevitably leads to reduced herd productivity. The seasonal infertility observed in domestic swine is primarily characterized by depressed reproductive performance manifesting as delayed puberty onset, reduced farrowing rates, and extended weaning-to-estrus intervals. Understanding the effects of heat stress at the organismal, cellular, and molecular level is a prerequisite to identifying mitigation strategies that could reduce the economic burden of compromised reproduction. Additionally, hyperthermia experienced in utero influences industry-relevant postnatal phenotypes. Understanding tissue-specific molecular mechanisms through which heat stress confers suppressed reproductive ability is essential to the development of mitigation focused hypothesis driven solutions. This work was supported by the National Pork Board and the Iowa Pork Producers Association.

Human Ovarian Cancer Tumor Formation in Severe Combined Immunodeficient (SCID) Pigs

Ovarian cancer (OvCa) is the most lethal gynecologic malignancy, with two-thirds of patients having late-stage disease (II-IV) at diagnosis. Improved diagnosis and therapies are needed, yet preclinical animal models for ovarian cancer research have primarily been restricted to rodents, for data on which can fail to translate to the clinic. Thus, there is currently a need for a large animal OvCa model. Therefore, we sought to determine if pigs, being more similar to humans in terms of anatomy and physiology, would be a viable preclinical animal model for OvCa. We injected human OSPC-ARK1 cells, a chemotherapy-resistant primary ovarian serous papillary carcinoma cell line, into the neck muscle and ear tissue of four severe combined immune deficient (SCID) and two non-SCID pigs housed in novel biocontainment facilities to study the ability of human OvCa cells to form tumors in a xenotransplantation model. Tumors developed in ear tissue of three SCID pigs, while two SCID pigs developed tumors in neck tissue; no tumors were detected in non-SCID control pigs. All tumor masses were confirmed microscopically as ovarian carcinomas. The carcinomas in SCID pigs were morphologically similar to the original ovarian carcinoma and had the same immunohistochemical phenotype based on expression of Claudin 3, Claudin 4, Cytokeratin 7, p16, and EMA. Confirmation that OSPC-ARK1 cells form carcinomas in SCID pigs substantiates further development of orthotopic models of OvCa in pigs.

Creating effective biocontainment facilities and maintenance protocols for raising specific pathogen-free, severe combined immunodeficient (SCID) pigs

Severe combined immunodeficiency (SCID) is defined by the lack of an adaptive immune system. Mutations causing SCID are found naturally in humans, mice, horses, dogs, and recently in pigs, with the serendipitous discovery of the Iowa State University SCID pigs. As research models, SCID animals are naturally tolerant of xenotransplantation and offer valuable insight into research areas such as regenerative medicine, cancer therapy, as well as immune cell signaling mechanisms. Large-animal biomedical models, particularly pigs, are increasingly essential to advance the efficacy and safety of novel regenerative therapies on human disease. Thus, there is a need to create practical approaches to maintain hygienic severe immunocompromised porcine models for exploratory medical research. Such research often requires stable genetic lines for replication and survival of healthy SCID animals for months post-treatment. A further hurdle in the development of the ISU SCID pig as a biomedical model involved the establishment of facilities and protocols necessary to obtain clean SPF piglets from the conventional pig farm on which they were discovered. A colony of homozygous SCID boars and SPF carrier sows has been created and maintained through selective breeding, bone marrow transplants, innovative husbandry techniques, and the development of biocontainment facilities.

Physiological mechanisms through which heat stress compromises reproduction in pigs

Seasonal variations in environmental temperatures impose added stress on domestic species bred for economically important production traits. These heat-mediated stressors vary on a seasonal, daily, or spatial scale, and negatively impact behavior and reduce feed intake and growth rate, which inevitably lead to reduced herd productivity. The seasonal infertility observed in domestic swine is primarily characterized by depressed reproductive performance, which manifests as delayed puberty onset, reduced farrowing rates, and extended weaning-to-estrus intervals. Understanding the effects of heat stress at the organismal, cellular, and molecular level is a prerequisite to identifying mitigation strategies that should reduce the economic burden of compromised reproduction. In this review, we discuss the effect of heat stress on an animal's ability to maintain homeostasis in multiple systems via several hypothalamic-pituitary-end organ axes. Additionally, we discuss our understanding of epigenetic programming and how hyperthermia experienced in utero influences industry-relevant postnatal phenotypes. Further, we highlight the recent recognized mechanisms by which distant tissues and organs may molecularly communicate via extracellular vesicles, a potentially novel mechanism contributing to the heat-stress response.

Using CRISPR-Cas9 to Generate Gene-Corrected Autologous iPSCs for the Treatment of Inherited Retinal Degeneration

Patient-derived induced pluripotent stem cells (iPSCs) hold great promise for autologous cell replacement. However, for many inherited diseases, treatment will likely require genetic repair pre-transplantation. Genome editing technologies are useful for this application. The purpose of this study was to develop CRISPR-Cas9-mediated genome editing strategies to target and correct the three most common types of disease-causing variants in patient-derived iPSCs: (1) exonic, (2) deep intronic, and (3) dominant gain of function. We developed a homology-directed repair strategy targeting a homozygous Alu insertion in exon 9 of male germ cell-associated kinase (MAK) and demonstrated restoration of the retinal transcript and protein in patient cells. We generated a CRISPR-Cas9-mediated non-homologous end joining (NHEJ) approach to excise a major contributor to Leber congenital amaurosis, the IVS26 cryptic-splice mutation in CEP290, and demonstrated correction of the transcript and protein in patient iPSCs. Lastly, we designed allele-specific CRISPR guides that selectively target the mutant Pro23His rhodopsin (RHO) allele, which, following delivery to both patient iPSCs in vitro and pig retina in vivo, created a frameshift and premature stop that would prevent transcription of the disease-causing variant. The strategies developed in this study will prove useful for correcting a wide range of genetic variants in genes that cause inherited retinal degeneration.

Detection of miRNA in Mammalian Oocytes and Embryos

MicroRNAs (miRNAs) play a crucial role in the regulation of many post-transcriptional processes in reproductive cells. Regulation of maternal mRNA translation and activation of zygotic mRNA are essential to successful embryonic development. Moreover, the precise development of embryonic cell and/or tissue lineages requires temporal and spatial control of gene expression, mRNA abundance, and translation into proteins, which is in part regulated via miRNA. Here, we describe some key protocols that can be utilized to detect and quantify miRNA in in vitro produced oocytes and embryos.