ABSTRACT
Male infertility affects approximately 7% of childbearing couples and is a major health issue. Although nearly 50% idiopathic infertile men are assumed to have a genetic basis, the underlying causes remain largely unknown in most infertility cases. Here, we report two rare homozygous variants in two previously uncharacterized genes, C9orf131 and C10orf120, identified in two unrelated men with asthenozoospermia. Both genes were predominantly expressed in the testes. Furthermore, C9orf131 and C10orf120 knockout mice were successfully generated using the CRISPR-Cas9 technology. However, both C9orf131-/- and C10orf120-/- adult male mice were fertile, with testis-to-body weight ratios comparable to those of wild-type mice. No overt differences were found between wild-type, C9orf131-/-, and C10orf120-/- mice regarding testicular/epididymal tissue morphology, sperm count, sperm motility, or sperm morphology. Moreover, TUNEL assays indicated that the number of apoptotic germ cells in testes was not significantly different between the three groups. In summary, these findings suggest that C9orf131 and C10orf120 are redundant genes in male infertility.
Subject(s)
Asthenozoospermia , Fertility , Fertility/genetics , Humans , Mice , Asthenozoospermia/genetics , Mice, Knockout , Testis/anatomy & histology , Male , Sperm Motility , Sperm Count , Spermatozoa/cytology , In Situ Nick-End Labeling , AnimalsABSTRACT
Diabetic retinopathy (DR) is a main factor affecting vision of patients, and its pathogenesis is not completely clear. The purpose of our study was to investigate correlations between MST2 and DR progression, and to study the possible mechanism of MST2 and its down pathway in high glucose (HG)-mediated RGC-5 apoptosis. The diabetic rat model was established by intraperitoneal injection of streptozotocin (STZ) 60 mg/kg. HE and TUNEL staining were used to evaluate the pathological changes and apoptosis of retinal cells in rats. Western blot, qRT-PCR and immunohistochemistry showed that levels of MST2 were increased in diabetic group (DM) than control. In addition, the differential expression of MST2 is related to HG-induced apoptosis of RGC-5 cells. CCK-8 and Hoechst 33,342 apoptosis experiments showed that MST2 was required in HG-induced apoptosis of RGC-5 cells. Further research revealed that MST2 regulated the protein expression of YAP1 at the level of phosphorylation in HG-induced apoptosis. Simultaneously, we found that Xmu-mp-1 acts as a MST2 inhibitor to alleviate HG-induced apoptosis. In summary, our study indicates that the MST2/YAP1 signaling pathway plays an important role in DR pathogenesis and RGC-5 apoptosis. This discovery provides new opportunities for future drug development targeting this pathway to prevent DR.
Subject(s)
Diabetes Mellitus, Experimental , Diabetic Retinopathy , Humans , Rats , Animals , Diabetic Retinopathy/metabolism , Diabetic Retinopathy/pathology , Diabetes Mellitus, Experimental/complications , Signal Transduction , Apoptosis , In Situ Nick-End LabelingABSTRACT
To investigate the feasibility of detection of apoptosis in vivo by 99mTc-HYNIC-Annexin V, Annexin V was labeled with 99mTc through HYNIC. 18 New Zealand rabbits implanted VX-2 were randomly divided into control (n = 8) and paclitaxel (PAC, n = 10) groups, given 2 mL/kg of normal saline or 2.4 mg/kg of PAC intravenously. The liver tumor imaging was detected by SPECT through intravenous injection of 99mTc-HYNIC-Annexin V before treatment, 24 hours and 48 hours after treatment respectively. Tumor radioactive count proportion to non-tumor sites was calculated. When the last imaging was finished, the rabbits were sacrificed. The tumor was taken out and divided into two pieces, one for TUNEL immunohistochemical analysis and the other for flow cytometry (FCM). We found that the rate of Annexin V labeled with 99mTc through HYNIC was more than 95%, and radiochemical purity was above 95%. The SPECT showed that two groups had no significant tumor imaging before the treatment. There is no significant tumor imaging in control group, while the PAC group 24 h and 48 h after treatment showed significant accumulation. The Tumor/non-Tumor (T/NT) in PAC group at 24 h and 48 h after chemotherapy was significantly different from that in the control group and PAC group prior to treatment. There was no significant difference between 24 h and 48 h in PAC group. The TUNEL-positive cells detected by immunohistochemistry and apoptotic rate detected by FCM in PAC group were significant different from those in control group. The T/NT was significantly correlated to TUNEL-positive cells and apoptotic rate of the tumor. PAC can induce apoptosis of rabbit VX-2 liver cancer cells. 24-48 h after paclitaxel chemotherapy is a window time for apoptosis detection. Apoptotic cells in vivo can be detected by SPECT through 99mTc-HYNIC-Annexin V.
Subject(s)
Annexin A5 , Apoptosis , Liver Neoplasms , Organotechnetium Compounds , Tomography, Emission-Computed, Single-Photon , Animals , Rabbits , Apoptosis/drug effects , Annexin A5/metabolism , Annexin A5/chemistry , Organotechnetium Compounds/chemistry , Tomography, Emission-Computed, Single-Photon/methods , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/pathology , Liver Neoplasms/metabolism , Liver Neoplasms/drug therapy , Disease Models, Animal , In Situ Nick-End Labeling , Paclitaxel/pharmacology , Radiopharmaceuticals/chemistry , Flow Cytometry , Cell Line, TumorABSTRACT
INTRODUCTION: This study aimed to investigate the characteristics of retinal vascular degeneration and the expression of vessel-related claudin (CLD) proteins in retinal degeneration mouse (Pde6ßrd1/rd1 rd1 mouse). METHODS: Retinas from wild-type (WT) mice and rd1 mice at postnatal day 3 (P3), P5, P8, P11, P13, P15, P18, and P21 were collected. Immunofluorescence staining was used to assess the retinal vascular plexus, cell proliferation, CLD expression, and retinal ganglion cells (RGCs). The distribution of retinal superficial and deep vessels was determined by isolectin B4 fluorescence staining of retinal flat mounts and frozen sections. Hematoxylin and eosin staining and terminal deoxynucleotidyl transferase-mediated dNTP nick-end labeling were used to investigate retinal histological degeneration and apoptosis in rd1 mice, respectively. Quantitative real-time PCR and Western blot were used to measure the expression of vessel-related CLD-1, -2, -3, and -5, vascular endothelial growth factor A (VEGFA), and vascular endothelial growth factor receptor 2 (VEGFR2) in the retinas. RESULTS: Compared to the WT mice, the rd1 mice displayed delayed but completed progressive development in the retinal superficial vascular plexuses (SVPs) and deep vascular plexuses (DVPs). In the rd1 mice, the thickness of retinal layers gradually decreased and the retinas underwent progressive atrophy and degeneration. The deterioration got worse at the late developmental stage. The declined vessel density of SVP and DVP correlated with the decreased thickness of the full and inner parts of the retina and the reduced number of RGCs. DVP degeneration and the thinning of the outer nuclear layer exhibited an obvious reduction at P15. The expression levels of CLD-1, CLD-2, CLD-3, CLD-5, VEGFA, and VEGFR2 decreased and were consistently lower in the rd1 mice than in WT mice since P15. CONCLUSION: Rd1 mice exhibited progressive vascular degeneration of retinal SVP and DVP, the thinning and atrophy of retinal ONL and RGC, and the downregulation of vessel-related CLD proteins during the late developmental period. Thus, the rd1 mouse is a useful model of not only retinal neuro-degeneration but also retinal vascular degeneration.
Subject(s)
Blotting, Western , Claudins , Disease Models, Animal , Mice, Inbred C57BL , Retinal Degeneration , Retinal Ganglion Cells , Retinal Vessels , Animals , Mice , Retinal Degeneration/metabolism , Retinal Degeneration/pathology , Retinal Degeneration/genetics , Retinal Vessels/pathology , Retinal Vessels/metabolism , Claudins/genetics , Claudins/metabolism , Claudins/biosynthesis , Retinal Ganglion Cells/pathology , Retinal Ganglion Cells/metabolism , Real-Time Polymerase Chain Reaction , Vascular Endothelial Growth Factor A/metabolism , Vascular Endothelial Growth Factor A/genetics , Apoptosis , Cell Proliferation , In Situ Nick-End Labeling , Gene Expression Regulation , Vascular Endothelial Growth Factor Receptor-2/metabolism , Vascular Endothelial Growth Factor Receptor-2/geneticsABSTRACT
BACKGROUND: Circular RNAs (circRNAs) are implicated in retinal pathophysiology; however, their expression profiles and functions in photoreceptor apoptosis are largely unknown. We explored circRNA-expression profiles and circUvrag (host gene: Uvrag, ultraviolet radiation resistance associated gene) function in light-induced photoreceptor apoptosis. METHODS: Sprague-Dawley rats and 661 W photoreceptor cells were exposed to blue light to establish light-induced photoreceptor degeneration. Differentially expressed circRNAs were identified using microarrays. Potential functions of dysregulated circRNAs were analysed using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. CircUvrag expression and localization were evaluated using quantitative RT-PCR and fluorescence in situ hybridization, respectively. CircUvrag overexpression and knockdown were induced using a plasmid and a small interfering RNA, respectively, and retinal function and structure were assessed using scotopic electroretinography, haematoxylin-eosin staining, and TUNEL staining. Microglial migration was assessed using IBA1 immunostaining. The apoptosis ratio of photoreceptor cells in vitro was detected using flow cytometry. RESULTS: We identified 764 differentially expressed circRNAs, which were potentially related with the development of retinal structures, including neurons, dendrites, and synapses, and might participate in nervous-system pathophysiology. Light exposure enriched circUvrag in the cytoplasm of photoreceptors in the outer nuclear layer (ONL). CircUvrag knockdown decreased photoreceptor apoptosis and microglial migration to the ONL after light exposure, preserving ONL thickness and a-wave amplitude. In vitro, circUvrag knockdown inhibited photoreceptor apoptosis, although circUvrag overexpression slightly promoted photoreceptor apoptosis. CONCLUSIONS: CircUvrag knockdown attenuated light-induced photoreceptor apoptosis, and might be a potential target in retinal degeneration.
Subject(s)
Apoptosis , Light , Photoreceptor Cells, Vertebrate , RNA, Circular , RNA , Rats, Sprague-Dawley , Retinal Degeneration , Animals , RNA, Circular/genetics , Retinal Degeneration/genetics , Retinal Degeneration/metabolism , Retinal Degeneration/etiology , Retinal Degeneration/physiopathology , Rats , Photoreceptor Cells, Vertebrate/pathology , Photoreceptor Cells, Vertebrate/metabolism , Light/adverse effects , RNA/genetics , In Situ Hybridization, Fluorescence , Gene Expression Regulation , Disease Models, Animal , Electroretinography , Radiation Injuries, Experimental/genetics , Radiation Injuries, Experimental/metabolism , Real-Time Polymerase Chain Reaction , Gene Expression Profiling , In Situ Nick-End Labeling , Male , Flow CytometryABSTRACT
Several clinical laboratories assess sperm DNA fragmentation (sDF) in addition to semen analysis in male infertility diagnosis. Among tests evaluating sDF, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) and SCD (Sperm Chromatin Dispersion) are widely used. Our lab developed a modified version of TUNEL (TUNEL/PI) able to distinguish two sperm populations (PI Brighter and PI Dimmer) differently associated with sperm viability and reproductive outcomes. The aim of this study was to compare sDF levels detected by SCD and TUNEL/PI in the semen samples from 71 male subjects attending our Andrology Laboratory. Our results demonstrate that SCD is less sensitive in determining sDF compared to TUNEL/PI. The statistically significant positive correlation found between sDF evaluated by SCD and PI Dimmer (consisting of all dead spermatozoa) suggests that SCD mainly detects sDF in unviable spermatozoa. We confirmed that most spermatozoa detected by SCD are unviable by performing SCD after incubation in hypo-osmotic medium to discriminate viable and unviable cells in 52 samples. Such results might explain the lower ability of this test in discriminating couples having successful ART outcomes demonstrated in published metanalyses. Overall, our results indicate that SCD is less sensitive in evaluating sDF for diagnostic purposes.
Subject(s)
Chromatin , DNA Fragmentation , In Situ Nick-End Labeling , Semen Analysis , Spermatozoa , Male , Humans , Spermatozoa/metabolism , Chromatin/metabolism , In Situ Nick-End Labeling/methods , Semen Analysis/methods , Adult , Infertility, Male/diagnosis , Infertility, Male/geneticsABSTRACT
PURPOSE: Age-related cataract (ARC) is the most common cause of visual impairment and blindness in older adults. However, the role of CUL4B in the ARC remains unclear. Therefore, we investigated CUL4B expression and its effects on apoptosis. MATERIALS AND METHODS: CUL4B expression levels were detected by a quantitative real-time polymerase chain reaction from the anterior lens capsules of patients with ARC and HLE-B3 cells treated with different concentrations of H2O2. CUL4B expression was silenced by siRNA transfection to evaluate apoptosis. CUL4B and apoptotic proteins B cell lymphoma 2 (Bcl-2), myeloid cell leukemia 1 (Mcl-1), caspase-3, cleaved caspase-3, Bax, Bak, and Bid were assessed using western blot analysis. Apoptosis was monitored using the TUNEL assay. RESULTS: CUL4B expression was downregulated in the anterior lens capsules (P < 0.0001) and H2O2-treated HLE-B3 cells (P = 0.0405). CUL4B protein levels were significantly lower in 100 µmol/L (P = 0.0012) and 200 µmol/L (P = 0.0041) H2O2-treated HLE-B3 cells than in the untreated cells. CUL4B expression was significantly knocked down at the mRNA (P = 0.0043) and protein levels (P = 0.0002) in HLE-B3 cells. Bcl-2 (P = 0.0199), Mcl-1 (P = 0.0042), and caspase-3 (P = 0.0142) were significantly downregulated, whereas cleaved caspase-3 (P = 0.0089) and Bak (P = 0.009) were significantly upregulated in the knockdown group. The TUNEL assay showed a greater induction of apoptosis. CONCLUSIONS: CUL4B downregulation promotes the apoptosis of lens epithelial cells. Our study may help in understanding the role of CUL4B in ARC pathogenesis.
Subject(s)
Apoptosis , Cataract , Cullin Proteins , Humans , Cataract/metabolism , Cataract/genetics , Cataract/etiology , Cullin Proteins/genetics , Cullin Proteins/metabolism , Cullin Proteins/biosynthesis , Male , Female , Aged , Blotting, Western , Real-Time Polymerase Chain Reaction , Middle Aged , Aging , Gene Expression Regulation , Lens Capsule, Crystalline/metabolism , Lens Capsule, Crystalline/pathology , In Situ Nick-End LabelingABSTRACT
There are an increasing number of experiments to study programmed cell death/apoptosis, one of the characteristics of which is DNA fragmentation. The only current method for in situ detection of DNA fragmentation is Terminal deoxynucleotidyl transferase mediated-dUTP Nick End Labeling, TUNEL. In this study, a new method for in situ detection of apoptotic DNA fragments, namely In Situ Hybridization Chain Reaction, isHCR, was established. The principle of the assay is that the sticky end sequence of the apoptotic cell DNA fragment non-specifically initiates a hybridization chain reaction that specifically detects the apoptotic cell. The results of the combined TUNEL and isHCR method demonstrated that the majority of isHCR-positive cells were also labeled by TUNEL. In situ HCR often detect DNA fragments in the cytoplasm that the classical TUNEL method couldnot, and these cells may be in the early stages of apoptosis. It also indicates that DNA fragments are transferred to the cytoplasm during apoptosis. Because the staining process does not require terminal deoxynucleotidyl transferase as TUNEL staining does, isHCR staining cost low and can be performed on a large number of tissue specimens. It is believed that isHCR has the potential to detect DNA fragmentation of apoptotic cells in situ.
Subject(s)
Apoptosis , DNA Nucleotidylexotransferase , Apoptosis/genetics , DNA Nucleotidylexotransferase/genetics , In Situ Nick-End Labeling , DNA Fragmentation , DNA , In Situ HybridizationABSTRACT
The Golgi-associated RAB GTPases, RAB6A and RAB6A', regulate anterograde and retrograde transport pathways from and to the Golgi. In vitro, RAB6A/A' control several cellular functions including cell division, migration, adhesion and polarity. However, their role remains poorly described in vivo Here, we generated BlgCre; Rab6aF/F mice presenting a specific deletion of Rab6a in the mammary luminal secretory lineage during gestation and lactation. Rab6a loss severely impaired the differentiation, maturation and maintenance of the secretory tissue, compromising lactation. The mutant epithelium displayed a decreased activation of STAT5, a key regulator of the lactogenic process primarily governed by prolactin. Data obtained with a mammary epithelial cell line suggested that defective STAT5 activation might originate from a perturbed transport of the prolactin receptor, altering its membrane expression and signaling cascade. Despite the major functional defects observed upon Rab6a deletion, the polarized organization of the mammary epithelial bilayer was preserved. Altogether, our data reveal a crucial role for RAB6A/A' in the lactogenic function of the mammary gland and suggest that the trafficking pathways controlled by RAB6A/A' depend on cell-type specialization and tissue context.
Subject(s)
Mammary Glands, Human/metabolism , STAT5 Transcription Factor/metabolism , rab GTP-Binding Proteins/metabolism , Animals , Blotting, Western , Cell Line , Female , Flow Cytometry , Humans , In Situ Nick-End Labeling , Mammary Glands, Human/cytology , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , STAT5 Transcription Factor/genetics , rab GTP-Binding Proteins/geneticsABSTRACT
Background and Objectives: Sperm DNA fragmentation refers to any break in one or both of the strands of DNA in the head of a sperm. The most widely used methodologies for assessing sperm DNA fragmentation are the sperm chromatin structure assay (SCSA), the sperm chromatin dispersion assay (SCD), the single-cell gel electrophoresis assay (SCGE-comet), and the terminal-deoxynucleotidyl-transferase (TdT)-mediated dUTP nick end labelling (TUNEL) assay. The aim of this study was to compare the efficiency and sensitivity of the analysis of sperm DNA fragmentation using TUNEL via fluorescence microscopy, and flow cytometry. Materials and Methods: Semen samples were collected and analyzed for standard characteristics using light microscopy, and for sperm DNA fragmentation using both TUNEL via fluorescence microscopy, and flow cytometry. Results: There were no significant differences in the values of the sperm DNA fragmentation index (DFI) obtained when the analysis was performed using TUNEL or flow cytometry (p = 0.543). Spearman's correlation analysis revealed a significant negative correlation between sperm motility (%) and sperm DNA fragmentation (p < 0.01), as well as between sperm concentration and sperm DNA fragmentation (p < 0.05). The Mann-Whitney U test showed no significant difference in the DFI among couples with repeated implantation failure (RIF) and miscarriages (p = 0.352). Conclusions: Both methods (TUNEL via fluorescence microscopy, and flow cytometry) have a high efficiency and sensitivity in accurately detecting sperm DNA fragmentation, and can be effectively used to assess male fertility.
Subject(s)
Semen Analysis , Semen , Male , Humans , DNA Fragmentation , Semen Analysis/methods , In Situ Nick-End Labeling , Flow Cytometry/methods , Sperm Motility , Spermatozoa , Chromatin , Microscopy, FluorescenceABSTRACT
Apoptosis is the best-known programmed cell death that maintains tissue homeostasis in eukaryotic cells. The morphological characteristics include nuclear and cytoplasmic contraction and cytoplasmic blebbing, its biochemical hallmarks include caspase protease activity and DNA fragmentation. In rat ovaries, cell death is a normal process that occurs throughout the organism's life. Granulosa cells, the more abundant cell type forming the ovarian follicles, are eliminated via different routes of cell death. Most granulosa cells are eliminated through apoptotic cell death. In this work, we analyzed the behavior of nuclear components throughout the apoptotic process and determined how they are regionalized and conserved during follicular atresia in rat ovaries. Apoptosis was detected based on caspase-3 activity and DNA fragmentation using the TUNEL technique. We identified the transcription markers H3ac and RNA Pol II, and splicing factor SC35 by immunodetection. The nucleolar components were analyzed via light microscopy and transmission electron microscopy through immunodetection of the proteins nucleolin and nucleophosmin-1. The nuclear ultrastructure was analyzed using standard contrast and preferential ribonucleoprotein contrast. Our results demonstrate that during the progression of apoptosis, chromatin is remodeled to constitute apoptotic bodies; transcription and spliceosome elements are reorganized along with the nucleolar components. Additionally, the splicing and transcription factors are segregated into specific territories inside the apoptotic bodies, suggesting that transcriptional elements are reorganized during the apoptotic process. Our results indicate that apoptotic bodies not only are compacted, and chromatin degraded but all the nuclear components are progressively reorganized during cell elimination; moreover, the transcriptional components are preserved.
Subject(s)
Apoptosis , Follicular Atresia , Animals , Apoptosis/genetics , Chromatin/genetics , Female , Follicular Atresia/metabolism , In Situ Nick-End Labeling , RNA Splicing Factors , RatsABSTRACT
Antibiotic screens typically rely on growth inhibition to characterize compound bioactivity-an approach that cannot be used to assess the bactericidal activity of antibiotics against bacteria in drug-tolerant states. To address this limitation, we developed a multiplexed assay that uses metabolism-sensitive staining to report on the killing of antibiotic-tolerant bacteria. This method can be used with diverse bacterial species and applied to genome-scale investigations to identify therapeutic targets against tolerant pathogens.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Drug Resistance, Bacterial , Escherichia coli/drug effects , Microbial Sensitivity Tests , Ciprofloxacin/pharmacology , DNA Damage , Escherichia coli/growth & development , Gene Deletion , In Situ Nick-End Labeling , Microscopy, Fluorescence , Mutation , Phenotype , Species SpecificityABSTRACT
Krüppel-like factor 2 (KLF2) belongs to the KLF family of zinc-finger transcription factors and mediates the occurrence and progression of various cancers. However, little is known about its expression pattern and biological role in retinoblastoma (RB). In the present study, we showed that KLF2 was markedly downregulated in human RB tissue compared with retina. KLF2 overexpression significantly inhibited RB cell proliferation and decreased proliferating cell nuclear antigen (PCNA) expression. Subsequently, we confirmed that KLF2 arrested cells at the G1-S phase transition, accompanied by the upregulation of p21 and downregulation of CyclinD1, as well as the activation of mitochondria-mediated apoptosis in RB cells. In addition, KLF2 overexpression contributed to suppressing RB cell migration and invasion by downregulating matrix metallopeptidase 9 (MMP9). On the contrary, KLF2 downregulation promoted RB cells proliferation, migration and invasion. Notably, the KLF2 expression pattern was opposite to that of C-X-C chemokine receptor 4 (CXCR4) in the two RB cell lines, KLF2 overexpression significantly decreased CXCR4 expression, silencing KLF2 had the opposite effect. Furthermore, dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays confirmed that KLF2 directly bound to the CXCR4 promoter and negatively regulated its expression in RB cells. Collectively, our results suggested that KLF2 function as a tumor suppressor in RB and may represent a potential therapeutic target for RB.
Subject(s)
Kruppel-Like Transcription Factors/physiology , Retinal Neoplasms/metabolism , Retinoblastoma/metabolism , Tumor Suppressor Proteins/physiology , Apoptosis/physiology , Blotting, Western , Cell Cycle/physiology , Cell Line, Tumor , Cell Proliferation/physiology , Cyclin D1/genetics , Gene Expression Regulation, Neoplastic/physiology , Humans , In Situ Nick-End Labeling , Plasmids , Proliferating Cell Nuclear Antigen/genetics , RNA, Small Interfering/genetics , Real-Time Polymerase Chain Reaction , Retinal Neoplasms/pathology , Retinoblastoma/pathology , Transfection , p21-Activated Kinases/geneticsABSTRACT
Retinal pigment epithelium (RPE) cell apoptosis arising from all-trans-retinal (atRAL) is in close contact with the etiology of dry age-related macular degeneration (AMD) and autosomal recessive Stargardt's disease (STGD1), but its underlying mechanisms remain elusive. In this study, we reported that c-Jun N-terminal kinase (JNK) activation facilitated atRAL-induced apoptosis of RPE cells. Reactive oxygen species production and endoplasmic reticulum stress were identified as two of major upstream events responsible for activating JNK signaling in atRAL-loaded RPE cells. Inhibiting JNK signaling rescued RPE cells from apoptosis induced by atRAL through attenuating caspase-3 activation leading to poly-ADP-ribose polymerase (PARP) cleavage, and DNA damage response. Abca4-/-Rdh8-/- mice upon light exposure exhibit rapidly increased accumulation of atRAL in the retina, and display severe RPE degeneration, a primary attribute of dry AMD and STGD1. Reducing JNK signaling by intraperitoneally injected JNK-IN-8 was highly effective in preventing RPE atrophy and apoptosis in light-exposed Abca4-/-Rdh8-/- mice. These findings afford a further understanding for contribution of JNK activation by atRAL to retinal damage.
Subject(s)
JNK Mitogen-Activated Protein Kinases/metabolism , Retinal Degeneration/prevention & control , Retinal Pigment Epithelium/pathology , Retinaldehyde/metabolism , Signal Transduction/physiology , ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Alcohol Oxidoreductases/genetics , Alcohol Oxidoreductases/metabolism , Animals , Apoptosis , Blotting, Western , Caspase 3/metabolism , Cells, Cultured , Chromatography, High Pressure Liquid , Endoplasmic Reticulum Stress/physiology , Fluorescent Antibody Technique, Indirect , Humans , In Situ Nick-End Labeling , Mice , Mice, Inbred C57BL , Mice, Knockout , Reactive Oxygen Species/metabolism , Retinal Degeneration/metabolism , Retinal Degeneration/pathology , Retinal Pigment Epithelium/metabolism , Zonula Occludens-1 Protein/metabolismABSTRACT
Zebrafish possess the ability to completely regenerate the retina following injury, however little is understood about the damage signals that contribute to inducing Müller glia reprogramming and proliferation to regenerate lost neurons. Multiple studies demonstrated that iron contributes to various retinal injuries, however no link has been shown between iron and zebrafish retinal regeneration. Here we demonstrate that Müller glia exhibit transcriptional changes following injury to regulate iron levels within the retina, allowing for increased iron uptake and decreased export. The response of the zebrafish retina to intravitreal iron injection was then characterized, showing that ferrous, and not ferric, iron induces retinal cell death. Additionally, iron chelation resulted in decreased numbers of TUNEL-positive photoreceptors and fewer proliferating Müller glia. Despite the contribution of iron to retinal cell death, inhibition of ferroptosis did not significantly reduce cell death following light treatment. Finally, we demonstrate that both the anti-ferroptotic protein Glutathione peroxidase 4b and the Transferrin receptor 1b are required for Müller glia proliferation following light damage. Together these findings show that iron contributes to cell death in the light-damaged retina and is essential for inducing the Müller glia regeneration response.
Subject(s)
Cell Proliferation/drug effects , Ependymoglial Cells/drug effects , Ferrous Compounds/toxicity , Photoreceptor Cells/drug effects , Radiation Injuries, Experimental/etiology , Retinal Degeneration/chemically induced , Animals , Animals, Genetically Modified , Apoptosis , Deferiprone/pharmacology , Ependymoglial Cells/metabolism , In Situ Nick-End Labeling , Intravitreal Injections , Light , Phospholipid Hydroperoxide Glutathione Peroxidase/metabolism , Photoreceptor Cells/radiation effects , Radiation Injuries, Experimental/metabolism , Receptors, Transferrin/metabolism , Retinal Degeneration/metabolism , Zebrafish , Zebrafish Proteins/metabolismABSTRACT
Lipocalin-2 (LCN2) has been implicated in promoting apoptosis and neuroinflammation in neurological disorders; however, its role in neural transplantation remains unknown. In this study, we cultured and differentiated Lund human mesencephalic (LUHMES) cells into human dopaminergic-like neurons and found that LCN2 mRNA was progressively induced in mouse brain after the intrastriatal transplantation of human dopaminergic-like neurons. The induction of LCN2 protein was detected in a subset of astrocytes and neutrophils infiltrating the core of the engrafted sites, but not in neurons and microglia. LCN2-immunoreactive astrocytes within the engrafted sites expressed lower levels of A1 and A2 astrocytic markers. Recruitment of microglia, neutrophils, and monocytes after transplantation was attenuated in LCN2 deficiency mice. The expression of M2 microglial markers was significantly elevated and survival of engrafted neurons was markedly improved after transplantation in LCN2 deficiency mice. Brain type organic cation transporter (BOCT), the cell surface receptor for LCN2, was induced in dopaminergic-like neurons after differentiation, and treatment with recombinant LCN2 protein directly induced apoptosis in dopaminergic-like neurons in a dose-dependent manner. Our results, therefore, suggested that LCN2 is a neurotoxic factor for the engrafted neurons and a modulator of neuroinflammation. LCN2 inhibition may be useful in reducing rejection after neural transplantation.
Subject(s)
Graft Rejection/metabolism , Lipocalin-2/metabolism , Lipocalin-2/physiology , Neurons/metabolism , Neurons/transplantation , Animals , Apoptosis/genetics , Apoptosis/physiology , Brain/cytology , Brain/metabolism , Cells, Cultured , Flow Cytometry , Graft Rejection/genetics , Humans , Immunohistochemistry , In Situ Nick-End Labeling , Lipocalin-2/genetics , Male , Mice , Mice, Inbred C57BL , Real-Time Polymerase Chain ReactionABSTRACT
Sjögren's syndrome (SS) is an autoimmune disease characterized by exocrinopathy that leads to dry eye and mouth. Although lymphocyte infiltration into exocrine glands and the generation of autoantibodies have been reported in SS, its pathogenic mechanism remains elusive. Here, we show that mice lacking the transcriptional regulator IκB-ζ developed SS-like inflammation characterized by lymphocyte-infiltrated dacryoadenitis and SS-associated autoantibodies. In particular, epithelial cells, but not hematopoietic cells, lacking IκB-ζ were essential for the development of inflammation. IκB-ζ-deficient epithelial cells in the lacrimal glands exhibited enhanced apoptosis even in the absence of lymphocytes. Administration of caspase inhibitors ameliorated the inflammation, indicating the critical role of caspase-mediated apoptosis. Furthermore, epithelial cell-specific STAT3-deficient mice developed SS-like inflammation with impaired IκB-ζ expression in the lacrimal glands. Thus, this study reveals a pathogenic mechanism of SS in which dysfunction of epithelial cells caused by disruption of STAT3-mediated IκB-ζ induction elicits the activation of self-reactive lymphocytes.
Subject(s)
Apoptosis/immunology , Autoimmune Diseases/immunology , Epithelial Cells/immunology , STAT3 Transcription Factor/immunology , Sjogren's Syndrome/immunology , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/immunology , Animals , Apoptosis/genetics , Autoimmune Diseases/genetics , Autoimmune Diseases/metabolism , Epithelial Cells/metabolism , Female , Immunohistochemistry , In Situ Nick-End Labeling , Inflammation/genetics , Inflammation/immunology , Inflammation/metabolism , Lacrimal Apparatus/immunology , Lacrimal Apparatus/metabolism , Lymphocytes/immunology , Lymphocytes/metabolism , Male , Mice , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Nuclear Proteins/genetics , Nuclear Proteins/immunology , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , Signal Transduction/genetics , Signal Transduction/immunology , Sjogren's Syndrome/genetics , Sjogren's Syndrome/metabolismABSTRACT
RESEARCH QUESTION: Does sperm DNA fragmentation (SDF) affect reproductive success of IVF and intracytoplasmic sperm injection (ICSI) cycles measured as cumulative live birth rates (CLBR) in unselected couples? DESIGN: Clinical data from 1339 couples undergoing 2759 IVF/ICSI cycles using autologous oocytes with a SDF test by TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labelling (TUNEL) assay on their ejaculated spermatozoa were retrospectively evaluated. Main outcomes were calculated according to two different analyses: using 15% SDF as cut-off point (low ≤15% and high >15%); and categorizing participants based on four SDF ranges (<10%, 10- <20%, 20-30% and >30%). Live birth rate and CLBR per number of embryo transfers, per number of embryos replaced and consumed oocytes required to achieve the first live birth according to level of SDF were the main outcomes assessed. RESULTS: No significant difference was found in clinical pregnancy rate and miscarriage rate between both groups. No differences in LBR per embryo transfer were found for the first or for all embryo transfers when comparing ≤15% and >15% sperm DNA fragmentation or by SDF ranges. The CLBR according to the number of embryo transfers and the number of embryos replaced showed no statistically significant differences between different SDF groups. When the same number of oocytes were inseminated, similar CLBR were obtained regardless of the degree of male sperm DNA fragmentation. CONCLUSIONS: High SDF did not impair live birth rates of unselected males undergoing IVF/ICSI cycles with autologous oocytes per transfer or the cumulative probability of a live birth.
Subject(s)
Birth Rate , Sperm Injections, Intracytoplasmic , DNA Fragmentation , Female , Fertilization in Vitro , Humans , In Situ Nick-End Labeling , Live Birth , Male , Oocytes , Pregnancy , Pregnancy Rate , Retrospective Studies , SpermatozoaABSTRACT
Thyroid hormones (THs) are important regulators of development, metabolism and homeostasis in metazoans. Specifically, they have been shown to regulate the metamorphic transitions of vertebrates and invertebrates alike. Indirectly developing sea urchin larvae accelerate the formation of juvenile structures in response to thyroxine (T4) treatment, while reducing their larval arm length. The mechanisms underlying larval arm reduction are unknown and we hypothesized that programmed cell death (PCD) is linked to this process. To test this hypothesis, we measured larval arm retraction in response to different THs (T4, T3, rT3, Tetrac) and assessed cell death in larvae using three different methods (TUNEL, YO-PRO-1 and caspase-3 activity) in the sea urchin Strongylocentrotus purpuratus. We also compared the extent of PCD in response to TH treatment before and after the invagination of the larval ectoderm, which marks the initiation of juvenile development in larval sea urchin species. We found that T4 treatment results in the strongest reduction of larval arms but detected a significant increase of PCD in response to T4, T3 and Tetrac in post-ingression but not pre-ingression larvae. As post-ingression larvae have initiated metamorphic development and therefore allocate resources to both larval and the juvenile structures, these results provide evidence that THs regulate larval development differentially via PCD. PCD in combination with cell proliferation likely has a key function in sea urchin development.
Subject(s)
Sea Urchins , Thyroid Hormones , Animals , Cell Death , Apoptosis , In Situ Nick-End Labeling , LarvaABSTRACT
Hepatic ischemia/reperfusion injury (IRI) is an adverse effect for liver transplantation which is characterized by immune response mediated inflammation. Recent studies report that neutrophil extracellular traps (NETs) are implicated in hepatic IRI. The aim of this study was to explore the mechanism of action of tetramethylpyrazine (TMP), the main chemical composition of Ligusticum chuanxiong in treatment of ischemic related diseases. Data showed that hepatic IRI increases the leak of alanine aminotransferase (ALT) and aspartate transaminase (AST), and stimulates formation of NETs. Extracellular DNA/NETs assay, hematoxylin-eosin (HE) staining, immunofluorescence assay, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and Western blot assay, showed that TMP significantly reduces formation of NETs and alleviates hepatic IRI. Moreover, TMP and Diphenyleneiodonium (DPI) suppressed ROS production in neutrophils. In addition, analysis showed that activation of NADPH oxidase plays a role in formation of NETs triggered by hepatic IRI. Notably, TMP inhibited formation of NETs though inhibition of NADPH oxidase. Additionally, Combination treatment using TMP and DPI was more effective compared with monotherapy of either of the two drugs. These findings show that combination therapy using TMP and DPI is a promising method for treatment hepatic IRI.