Publications by authors named "Jung-Jae Ko"

Non-obstructive azoospermia is a major clinical issue associated with male infertility that remains to be addressed. Although neogenin is reportedly abundantly expressed in the testis, its role in mammalian spermatogenesis is unknown. We systematically investigated the role of neogenin during spermatogenesis by performing loss-of-function studies.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on patient-derived induced pluripotent stem cells (iPSCs) from Alzheimer's disease (AD) patients to explore mitochondrial DNA (mtDNA) mutations and their effects on neuronal function.
  • Researchers found that iPSCs from AD patients had significantly more mtDNA mutations than those from umbilical cord blood, affecting mitochondrial performance and contributing to β-amyloid (Aβ) accumulation.
  • The results highlight the importance of screening mtDNA mutations in iPSC lines, as these mutations could lead to mitochondrial dysfunction and inform potential therapies for Alzheimer's disease.
View Article and Find Full Text PDF

Millions of people around the world suffer from infertility, with the number of infertile couples and individuals increasing every year. Assisted reproductive technologies (ART) have been widely developed in recent years; however, some patients are unable to benefit from these technologies due to their lack of functional germ cells. Therefore, the development of alternative methods seems necessary.

View Article and Find Full Text PDF

When ejaculated sperm travels through the vagina to the uterus, mucus secreted by the cervical canal generally filters out sperm having low motility and poor morphology. To investigate this selection principle in vivo, we developed a microfluidic sperm-sorting chip with a viscous medium (polyvinylpyrrolidone: PVP) to imitate the biophysical environment mimic system of the human cervical canal. The material property of the PVP solution was tuned to the range of viscosities of cervical mucus using micro-viscometry.

View Article and Find Full Text PDF

The maturation of the oocyte is influenced by cumulus cells (CCs) and associated with pregnancy rate, whereas the influencing factors have not been completely elucidated in the CCs. In this study, we identified new regulators of CCs for high-quality oocytes and successful pregnancies during assisted reproductive techniques. CCs were collected from cumulus-oocyte complexes (COCs) in young (≤33 years old) and old (≥40 years old) women undergoing intracytoplasmic sperm injection (ICSI) procedures.

View Article and Find Full Text PDF

The purpose of this study was to investigate whether polymorphisms in five microRNAs (miRNAs), A>G, C>G, I/D, G>A, and C>T, are associated with the risk of idiopathic recurrent pregnancy loss (RPL). Blood samples were collected from 388 patients with idiopathic RPL (at least two consecutive spontaneous abortions) and 227 control participants. We found the AG and AG + GG genotypes of , the GA and GA + AA genotypes of , and the CT and CT + TT genotypes of are less frequent than the wild-type (WT) genotypes, AA, GG, and CC, respectively, in RPL patients.

View Article and Find Full Text PDF

Inflammation is a major cause of several chronic diseases and is reported to be recovered by the immuno-modulation of mesenchymal stem cells (MSCs). While most studies have focussed on the anti-inflammatory roles of MSCs in stem cell therapy, the impaired features of MSCs, such as the loss of homeostasis by systemic aging or pathologic conditions, remain incompletely understood. In this study, we investigated whether the altered phenotypes of human placenta-derived MSCs (hPD-MSCs) exposed to inflammatory cytokines, including TNF-α and IFN-γ, could be protected by MIT-001, a small anti-inflammatory and anti-necrotic molecule.

View Article and Find Full Text PDF

There is currently no cure for infertility in women with a poor ovarian response (POR). Neogenin is reported to be abundantly expressed in the ovary; however, its role in mammalian follicular development is unclear and its ligand and signaling pathway remain uncertain. We systematically investigated the role of neogenin and the ligand repulsive guidance molecule c (RGMc) during follicular development.

View Article and Find Full Text PDF

Successful pregnancy inevitably depends on the implantation of a competent embryo into a receptive endometrium. Although many substances have been suggested to improve the rate of embryo implantation targeting enhancement of endometrial receptivity, currently there rarely are effective evidence-based treatments to prevent or cure this condition. Here we strongly suggest minimally-invasive intra-uterine administration of embryo-secreted chemokine CXCL12 as an effective therapeutic intervention.

View Article and Find Full Text PDF

Mesenchymal stem cells (MSCs) are multipotent cells with critical roles in homeostasis and regeneration. MSCs undergo aging in response to various stresses, and this causes many diseases including degenerative disorders. Thus, regulation of aging factors is crucial for healthy aging.

View Article and Find Full Text PDF

Background: Aging has detrimental effects on the ovary, such as a progressive reduction in fertility and decreased hormone production, that greatly reduce the quality of life of women. Thus, the current study was undertaken to investigate whether human placenta-derived mesenchymal stem cell (hPD-MSC) treatment can restore the decreases in folliculogenesis and ovarian function that occur with aging.

Methods: Acclimatized 52-week-old female SD rats were randomly divided into four groups: single hPD-MSC (5 × 10) therapy, multiple (three times, 10-day intervals) hPD-MSC therapy, control (PBS), and non-treated groups.

View Article and Find Full Text PDF

Objective: Despite extensive research on implantation failure, little is known about the molecular mechanisms underlying the crosstalk between the embryo and the maternal endometrium, which is critical for successful pregnancy. Profilin 1 (PFN1), which is expressed both in the embryo and in the endometrial epithelium, acts as a potent regulator of actin polymerization and the cytoskeletal network. In this study, we identified the specific role of endometrial PFN1 during embryo implantation.

View Article and Find Full Text PDF

Objective: Endometrial fibrosis, the primary pathological feature of intrauterine adhesion, may lead to disruption of endometrial tissue structure, menstrual abnormalities, infertility, and recurrent pregnancy loss. At present, no ideal therapeutic strategy exists for this fibrotic disease. Eupatilin, a major pharmacologically active flavone from Artemisia, has been previously reported to act as a potent inducer of dedifferentiation of fibrotic tissue in the liver and lung.

View Article and Find Full Text PDF

Sperm motility is a crucial factor for normal fertilisation that is partly supported by mitochondrial activity. Enzymatic biofuel cells (EBFCs) generate electric currents by an electron grade from anodic to cathodic electrodes in a culture media. We demonstrate that electrical stimulation by EBFC at the nano-Ampere range enhances sperm motility that can potentially allow the development of a new therapeutic tool for male infertility, including poor motility.

View Article and Find Full Text PDF

Mitochondrial dysfunction is strongly associated with the oocyte quality and aging, wherein the aged oocytes are related to the actin cytoskeleton integrity; however, whether this integrity is associated with mitochondrial dysfunction in oocytes from aged mice remains unclear. In the present study, we investigated the relationship between mitochondrial dysfunction and actin cytoskeleton instability in oocytes from the aged mice. We performed comparable analysis of mitochondrial motility between young, 1.

View Article and Find Full Text PDF

Previously, we found that the silencing of growth arrest-specific gene 6 (Gas6) expression in oocytes impairs cytoplasmic maturation through mitochondrial overactivation with concurrent failure of pronuclear formation after fertilization. In this study, we report that Gas6 regulates mitophagy and safeguards mitochondrial activity by regulating mitophagy-related genes essential to the complete competency of oocytes. Based on RNA-Seq and RT-PCR analysis, in Gas6-silenced MII oocytes, expressions of mitophagy-related genes were decreased in Gas6-silenced MII oocytes, while mitochondrial proteins and Ptpn11, the downstream target of Gas6, was increased.

View Article and Find Full Text PDF

Objective: The purpose of this study was to investigate the association of microRNA polymorphisms (miR-25T>C, miR-32C>A, miR-125C>T, and miR-222G>T) with primary ovarian insufficiency (POI) in Korean women.

Methods: We conducted a case-control study of Korean women: 142 participants with POI and 266 controls with at least 1 live birth and no history of pregnancy loss.

Results: The haplotype-based multifactor dimensionality reduction analysis revealed that the T-C-T-G (miR-25/-32/-125/-222), T-A-C-G (miR-25/-32/-125/-222), C-T-G (miR-32/-125/-222), A-C-G (miR-32/-125/-222), T-G (miR-122/-222), C-T (miR-32/-125), and C-C (miR-25/-32) inferred haplotypes were significantly less frequent in POI (P < 0.

View Article and Find Full Text PDF

Objectives: The aim of this study was to investigate the effects of the activated P2X7 receptors on the proliferation and growth of human pancreatic cancer cells.

Methods: Proliferation was measured by incorporating bromodeoxyuridine into pancreatic cancer cells, MIA PaCa-2 and HPAC. Expression of P2 receptors and signal molecules was examined using quantitative reverse transcription/polymerase chain reaction and/or Western blot.

View Article and Find Full Text PDF

Background/aims: Cyclic adenosine monophosphate (cAMP)-dependent type 2 regulatory subunit beta (Prkar2b) is a regulatory isoform of cAMP-dependent protein kinase (PKA), which is the primary target for cAMP actions. In oocytes, PKA and the pentose phosphate pathway (PPP) have important roles during the germinal vesicle (GV) stage arrest of development. Although the roles of the PKA signal pathway have been studied in the development of oocyte, there has been no report on the function of PRKAR2B, a key regulator of PKA.

View Article and Find Full Text PDF

Background/aims: Previously, we found that silencing of growth arrest-specific gene 6 (Gas6) in oocytes impaired cytoplasmic maturation, resulting in failure of sperm chromatin decondensation (SCD) and pronuclear (PN) formation after fertilization. Thus, we conducted this study to determine the effect of Gas6 RNAi on downstream genes and to elucidate the working mechanism of Gas6 on oocyte cytoplasmic maturation and SCD.

Methods: Using RT-PCR, Western blot and immunofluorescence, the expression levels of various target genes and the localization of heparan sulfate (HS) were analyzed after Gas6 RNAi.

View Article and Find Full Text PDF

MicroRNAs post-transcriptionally regulate gene expression in animals and plants. The aim of this study was to identify new target genes for microRNA polymorphisms (miR-146aC>G and miR-196a2T>C) in primary ovarian insufficiency (POI). We cloned and transfected miR-146aC>G and miR-196a2T>C into human granulosa cells and used microarrays and qPCR-arrays to examine the changes in the messenger RNA expression profile.

View Article and Find Full Text PDF

In previous studies, we observed that Zeta-chain-associated protein kinase 70 (Zap70) regulates spindle assembly and chromosome alignment in mouse oocyte and that Ran binding protein 2 (RanBP2) is a highly associated gene with Zap70 based on a microarray analysis. Because RanBP2 is related to nuclear envelope breakdown (NEBD) during mitosis, the aim of the present study was to elucidate the molecular mechanism of Zap70 with respect to RanBP2 in the germinal vesicle breakdown (GVBD) of oocytes. Results indicated that RanBP2 expression was regulated by Zap70 and that depletion of RanBP2 using RanBP2 RNAi manifested comparable phenotypes to those observed in Zap70 RNAi-treated oocytes, which presented faster processing of GVBD.

View Article and Find Full Text PDF

Premature ovarian failure during chemotherapy is a serious problem for young women with cancer. To preserve the fertility of these patients, approaches to prevent chemotherapy-induced ovarian failure are needed. In a previous study, we reported that melatonin treatment prevents the depletion of the dormant follicle pool via repression of the simultaneous activation of dormant primordial follicles by cisplatin.

View Article and Find Full Text PDF

MicroRNAs (miRNAs) post-transcriptionally regulate gene expression in animals and plants. The aim of this study was to investigate whether polymorphisms in are associated with the risk of primary ovarian insufficiency (POI) and POI-related target gene regulation. We identified the G>A polymorphisms within the seed sequence of mature miRNA and aligned the seed sequence with the 3' untranslated region (UTR) of the gonadotropin-releasing hormone receptor () mRNA, a miR-938 target gene.

View Article and Find Full Text PDF

Background: Ras dexamethasone-induced protein (RASD1) is a member of Ras superfamily of small GTPases. RASD1 regulates various signaling pathways involved in iron homeostasis, growth hormone secretion, and circadian rhythm. However, RASD1 function in oocyte remains unknown.

View Article and Find Full Text PDF