Identification of a novel embryo-prevalent gene, Gm11545, involved in preimplantation embryogenesis in mice.

In mammals, the early embryo travels down the oviduct to the uterus and prepares for implantation. The unique features of preimplantation development include compaction followed by blastocyst formation. This first cell lineage specification involves various proteins including cell polarity regulators, kinases, and transcription factors. In this study, a novel gene named predicted gene 11545 (Gm11545) expressed predominantly in mouse early embryos was identified and characterized at the transcript, protein, cellular, and functional levels. The Gm11545 protein localized to both cytoplasmic and membrane regions of preimplantation embryos. Remarkably, knockdown of Gm11545 led to arrest of mouse embryos at the morula stage and consequent impairment of blastocyst formation. Expression patterns of the key transcription factors critical for early lineage specification, octamer-binding transcription factor 4 and caudal type homeobox 2, were affected by Gm11545 depletion. Based on the collective findings, we propose that the novel protein identified in this study, Gm11545, is implicated in cell proliferation and cell lineage specification critical for blastocyst formation.-Kim, J., Kim, J., Jeong, J., Hong, S. H., Kim, D., Choi, S., Choi, I., Oh, J. S., Cho, C. Identification of a novel embryo-prevalent gene, Gm11545, involved in preimplantation embryogenesis in mice.

SPATC1L maintains the integrity of the sperm head-tail junction.

Spermatogenesis is a tightly regulated process involving germ cell-specific and germ cell-predominant genes. Here we investigate a novel germ cell-specific gene, Spatc1l (spermatogenesis and centriole associated 1 like). Expression analyses show that SPATC1L is expressed in mouse and human testes. We find that mouse SPATC1L localizes to the neck region in testicular sperm. Moreover, SPATC1L associates with the regulatory subunit of protein kinase A (PKA). Using CRISPR/Cas9-mediated genome engineering, we generate mice lacking SPATC1L. Disruption of Spatc1l in mice leads to male sterility owing to separation of sperm heads from tails. The lack of SPATC1L is associated with a reduction in PKA activity in testicular sperm, and we identify capping protein muscle Z-line beta as a candidate target of phosphorylation by PKA in testis. Taken together, our results implicate the SPATC1L-PKA complex in maintaining the stability of the sperm head-tail junction, thereby revealing a new molecular basis for sperm head-tail integrity.

Profiling of testis-specific long noncoding RNAs in mice.

BACKGROUND: Spermatogenesis, which is the complex and highly regulated process of producing haploid spermatozoa, involves testis-specific transcripts. Recent studies have discovered that long noncoding RNAs (lncRNAs) are novel regulatory molecules that play important roles in various biological processes. However, there has been no report on the comprehensive identification of testis-specific lncRNAs in mice. RESULTS: We performed microarray analysis of transcripts from mouse brain, heart, kidney, liver and testis. We found that testis harbored the highest proportion of tissue-specific lncRNAs (11%; 1607 of 14,256). Testis also harbored the largest number of tissue-specific mRNAs among the examined tissues, but the proportion was lower than that of lncRNAs (7%; 1090 of 16,587). We categorized the testis-specific lncRNAs and found that a large portion corresponded to long intergenic ncRNAs (lincRNAs). Genomic analysis identified 250 protein-coding genes located near (≤ 10 kb) 194 of the loci encoding testis-specific lincRNAs. Gene ontology (GO) analysis showed that these protein-coding genes were enriched for transcriptional regulation-related terms. Analysis of male germ cell-related cell lines (F9, GC-1 and GC-2) revealed that some of the testis-specific lncRNAs were expressed in each of these cell lines. Finally, we arbitrarily selected 26 testis-specific lncRNAs and performed in vitro expression analysis. Our results revealed that all of them were expressed exclusively in the testis, and 23 of the 26 showed germ cell-specific expression. CONCLUSION: This study provides a catalog of testis-specific lncRNAs and a basis for future investigation of the lncRNAs involved in spermatogenesis and testicular functions.

Reliability of an Electronic Inspiratory Loading Device for Assessing Pulmonary Function in Post-Stroke Patients.

BACKGROUND: The purpose of this study was to examine the inter- and intra-rater reliability of an electronic inspiratory loading device for the assessment of pulmonary functions: maximum inspiratory pressure, peak inspiratory flow, and vital capacity. MATERIAL/METHODS: Subjects were 50 patient volunteers in a rehabilitation hospital who had experienced their first episode of unilateral stroke with hemiparesis during the previous 6 months (26 men, 24 women; mean age [±SD], 55.96 [±12.81] years), with no use of medications that could induce drowsiness, evidence of restrictive lung disease, history of asthma, use of psychotropic drugs, or alcohol consumption habit. Maximum inspiratory pressure, peak inspiratory flow, and vital capacity for pulmonary functions were assessed using an electronic inspiratory loading device (PowerBreathe, K5, 2010) by 2 examiners, with patients in an unassisted sitting position, and 1 examiner re-assessed with same patients at the same time of a day after 1 week. Intra-class correlation coefficients were used to assess reliability. RESULTS: Intra-rater reliability ranged from intra-class correlation coefficients (ICCs)=0.959 to 0.986 in variables. For the inter-rater reliability between 2 examiners, the ICCs ranged from 0.933 to 0.985. Intra-rater and inter-rater reliability were good in variables (maximal inspiratory pressure, peak inspiratory flow, and vital capacity). CONCLUSIONS: The intra- and inter-examiner reliability of the pulmonary function measurements, maximum inspiratory pressure, peak inspiratory flow, and vital capacity, for the post-stroke patients was very high. The results suggest that the electronic inspiratory loading device would be useful for clinical rehabilitative assessment of pulmonary function.

Evaluation of research trends in physical therapy through analysis of articles published at the world confederation for physical therapy congress.

[Purpose] The purpose of this study was to examine research trends in physical therapy through analysis of articles published at the 2015 World Confederation for Physical Therapy Congress. [Subjects and Methods] A total of 1,339 were analyzed (presentations: 346, posters: 993). The number of papers per subject area, number of oral presentations and posters, and the number of moderator nations and regional publications were analyzed by subject area. The mean and standard deviation was used for statistical analysis. [Results] Of 1,339 items published, the musculoskeletal spine was the most common theme, with 89. Among oral presentations, 24 had cardiorespiratory themes; among poster presentations, themes related to the elderly were the most common, at 76. Eleven moderators were from Australia, and the most frequent regional source of papers was Japan, with 238. [Conclusion] The 2015 WCPT Congress published papers in a variety of subject areas; Australia and the UK presented many papers, but Japan had the most of any region, at 238.

Reduced Fertility and Altered Epididymal and Sperm Integrity in Mice Lacking ADAM7.

The mammalian epididymis is a highly convoluted tubule that connects the testis to the vas deferens. Its proper functions in sperm transport, storage, and maturation are essential for male reproduction. One of the genes predominantly expressed in the epididymis is ADAM7 (a disintegrin and metalloprotease 7). Previous studies have shown that ADAM7 synthesized in the epididymis is secreted into the epididymal lumen and is then transferred to sperm membranes, where it forms a chaperone complex that is potentially involved in sperm fertility. In this study, we generated and analyzed mice with a targeted disruption in the Adam7 gene. We found that the fertility of male mice was modestly but significantly reduced by knockout of Adam7. Histological analyses revealed that the cell heights of the epithelium were dramatically decreased in the caput of the epididymis of Adam7-null mice, suggesting a requirement for ADAM7 in maintaining the integrity of the epididymal epithelium. We found that sperm from Adam7-null mice exhibit decreased motility, tail deformation, and altered tyrosine phosphorylation, indicating that the absence of ADAM7 leads to abnormal sperm functions and morphology. Western blot analyses revealed reduced levels of integral membrane protein 2B (ITM2B) and ADAM2 in sperm from Adam7-null mice, suggesting a requirement for ADAM7 in normal expression of sperm membrane proteins involved in sperm functions. Collectively, our study demonstrates for the first time that ADAM7 is required for normal fertility and is important for the maintenance of epididymal integrity and for sperm morphology, motility, and membrane proteins.

The effect of trunk stabilization exercise using an unstable surface on the abdominal muscle structure and balance of stroke patients.

[Purpose] This study investigated the effect of unstable surface trunk stabilization exercise on the abdominal muscle structure and balance of stroke patients. [Subjects] The subjects were divided into two groups: an unstable surface trunk stabilization exercise group (n=13), and a stable surface trunk stabilization exercise group (n=11). [Methods] Both groups performed trunk stabilization exercise for 30 minutes, 3 days per week for 6 weeks. Abdominal muscle thickness and the Berg Balance Scale (BBS) were measured at the baseline and after 6 weeks. [Results] There was a significant improvement in the internal oblique muscle thickness, transversus abdominis thickness and balance ability of the unstable surface trunk stabilization exercise group. [Conclusion] The unstable surface trunk stabilization exercise improved the internal oblique and transversus abdominis muscles and balance ability. These results suggest that unstable surface trunk exercise is useful in the rehabilitation stroke patients.

A reliability of the prototype trunk training system for sitting balance.

[Purpose] Cerebral palsy is a disorder that affects balance in the sitting position. Cerebral palsy patients need trunk muscle strengthening and balance training. In order to improve trunk control sensory-motor control training is carried out on an unstable surface. We have developed a Trunk Training System (TTS) that can provide visual feedback using a tilt sensor for balance training in the sitting position. Before using the TTS for training children with cerebral palsy experiments were conducted with healthy adult subjects and the TTS to gather basic data for its improvement. [Subjects] The subjects were 11 healthy men (n=3) and women (n=8). [Methods] Subjects trained at two levels (5°, 10°), in four different directions (anterior, posterior, left, right), three times each. TTS outcome indices (stability index, performance time) were measured. [Results] The stability index and performance time showed high correlation (-0.6

Identification and characterization of promoter and regulatory regions for mouse Adam2 gene expression.

ADAM2, a member of the 'a disintegrin and metalloprotease' (ADAM) family, is a key protein in mammalian fertilization that is specifically expressed in testicular germ cells. Here, we investigated the transcriptional regulation of the mouse Adam2 gene. An in silico analysis identified two conserved non-coding sequences located upstream of the mouse and human ADAM2 genes. The upstream region of the mouse Adam2 gene was found to lack typical TATA and CAAT boxes, and to have a high GC content. Our in vitro transient transfection-reporter analysis identified a promoter in this region of the mouse Adam2 gene, along with regulatory regions that inhibit the activity of this promoter in somatic cells. Site-directed mutagenesis revealed that the caudal-type homeobox 1 and CCTC-binding factor motifs are responsible for the inhibitory activities of the repressor regions. Finally, electrophoretic mobility shift assays showed putative transcription factor-promoter DNA complexes, and DNA-affinity chromatography and proteomic analyses identified myelin gene regulatory factor as a binding partner of the Adam2 promoter. This provides the first identification and characterization of promoter and repressor regions that regulate the transcription of the mouse Adam2 gene, and offers insights into the regulation of this germ-cell-specific gene.

Health-promoting behaviors among middle-aged breast cancer survivors compared with matched non-cancer controls: A KNHANES VI-VII (2013-2018) study.

This study aimed to compare health-promoting behaviors between middle-aged breast cancer survivors and matched non-cancer controls. We conducted a retrospective, cross-sectional, matched case-control study using data from Korean National Health and Nutrition Examination Surveys (KNHANES) VI-VII (2013-2018) to compare health-promoting behaviors. We selected breast cancer survivors aged 40 to 65 who completed the surveys, and each case was matched with 5 non-cancer controls (1:5) based on propensity scores. With multivariable logistic regression, middle-aged breast cancer survivors were compared with controls in terms of their last screening for a second primary cancer (SPC), current smoking status, alcohol consumption, aerobic physical activity (PA), sedentary time, and self-reported diet control. The final study sample consisted of 117 middle-aged breast cancer survivors and 585 non-cancer controls after propensity score matching (PSM). In the multivariable analysis, middle-aged breast cancer survivors were less likely to consume alcohol (odds ratio [OR] 0.58, 95% confidence interval [CI], 0.35-0.95), more likely to engage in aerobic PA (OR, 1.60; 95% CI, 1.01-2.54), and more likely to self-report diet control (OR, 2.12; 95% CI, 1.27-3.53). There were no significant intergroup differences in SPC screening uptake within 2 years, smoking status, or sedentary times. There is a need to educate middle-aged breast cancer survivors about SPC screening, smoking cessation, and minimizing sedentariness to reduce the risks of associated with breast cancer recurrence, SPCs, and comorbid chronic diseases.

Effective Timing of Introducing an Inpatient Smoking Cessation Program to Cancer Patients.

PURPOSE: We aimed to identify factors influencing smoking cessation success among cancer patients registered in an inpatient smoking cessation program at a single cancer center. MATERIALS AND METHODS: The electronic medical records of enrolled patients with solid cancer were retrospectively reviewed. We evaluated factors associated with 6-month smoking cessation. RESULTS: A total of 458 patients with cancer were included in this study. Their mean age was 62.9±10.3 years, and 56.3% of the participants had lung cancer. 193 (42.1%) had not yet begun their main treatment. The mean number of counseling sessions for the participants was 8.4±3.5, and 46 (10.0%) patients were prescribed smoking cessation medications. The 6-month smoking cessation success rate was 48.0%. Multivariate analysis showed that younger age (<65 years), cohabited status, early stage, and the number of counseling sessions were statistically significant factors affecting 6-month smoking cessation success (p<0.05). Initiation of a cessation program before cancer treatment was significantly associated with cessation success (odds ratio, 1.66; 95% confidence interval, 1.02-2.70; p=0.040). CONCLUSION: Smoking cessation intervention must be considered when establishing a treatment plan immediately after a cancer diagnosis among smokers.

Impaired spermatogenesis and fertility in mice carrying a mutation in the Spink2 gene expressed predominantly in testes.

Spermatogenesis is a complex process involving an intrinsic genetic program composed of germ cell-specific and -predominant genes. In this study, we investigated the mouse Spink2 (serine protease inhibitor Kazal-type 2) gene, which belongs to the SPINK family of proteins characterized by the presence of a Kazal-type serine protease inhibitor-pancreatic secretory trypsin inhibitor domain. We showed that recombinant mouse SPINK2 has trypsin-inhibitory activity. Distribution analyses revealed that Spink2 is transcribed strongly in the testis and weakly in the epididymis, but is not detected in other mouse tissues. Expression of Spink2 is specific to germ cells in the testis and is first evident at the pachytene spermatocyte stage. Immunoblot analyses demonstrated that SPINK2 protein is present in male germ cells at all developmental stages, including in testicular spermatogenic cells, testicular sperm, and mature sperm. To elucidate the functional role of SPINK2 in vivo, we generated mutant mice with diminished levels of SPINK2 using a gene trap mutagenesis approach. Mutant male mice exhibit significantly impaired fertility; further phenotypic analyses revealed that testicular integrity is disrupted, resulting in a reduction in sperm number. Moreover, we found that testes from mutant mice exhibit abnormal spermatogenesis and germ cell apoptosis accompanied by elevated serine protease activity. Our studies thus provide the first demonstration that SPINK2 is required for maintaining normal spermatogenesis and potentially regulates serine protease-mediated apoptosis in male germ cells.

Relationship between frailty and mortality after gastrectomy in older patients with gastric cancer.

OBJECTIVES: Frail older adults with gastric cancer are at an increased risk of poor postoperative outcomes. We assessed whether geriatric frailty assessed using the Study of Osteoporotic Fractures (SOF) index could predict post-gastrectomy mortality. MATERIALS AND METHODS: We retrospectively assessed older adults (age ≥ 65 years) who underwent gastrectomy for gastric cancer between April 2012 and September 2015. Frailty status was assessed using the SOF index (range, 0-3) and categorized as robust (0), pre-frail (1), and frail (2-3). The Kaplan-Meier method and log-rank tests were used to compare survival between frailty groups. Univariate and multivariate analyses were used to identify mortality-associated risk factors. RESULTS: Among 231 patients (the median age 72.04 years and 140 (60.6%) men), 138 (59.7%) were robust, 58 (25.1%) were pre-frail, and 35 (15.2%) were frail. The mortality rate was 14.5% among robust patients, 20.7% among pre-frail patients, and 20.0% among frail patients (log-rank test, P = 0.032). Frail patients had more than a 3-fold increased risk of mortality compared with robust patients (adjusted HR = 3.331; 95% CI, 1.161-9.559). Multivariate analysis revealed that the SOF index and TNM stage were associated with increased mortality. CONCLUSIONS: SOF index predicted post-gastrectomy mortality among older patients independently of age, sex, TNM stage, type of approach, gastrectomy type, and extent of lymph node dissection. SOF index may be used with ease to assess frailty status among older patients with gastric cancer in busy clinics and subgroups that may benefit from targeted frailty interventions before cancer treatments.

Grip strength mediates the relationship between muscle mass and frailty.

BACKGROUND: Although sarcopenia and frailty are important diseases in geriatrics, few studies have investigated the association between the two diseases. Thus, this study aimed to examine the relationship between two components of sarcopenia (muscle mass and muscle function) and frailty. METHODS: In total, 997 Korean older adults (456 men and 541 women) were included in this cross-sectional observational study. We used a polynomial linear regression analysis to obtain standardized sex, age, and height-adjusted appendicular skeletal muscle mass (zASM), as well as to standardized sex, age, and height-adjusted grip strength (zGS). We then performed a causal mediation analysis to confirm the relationship between zASM and frailty. RESULTS: In both men and women, zGS mediated the relationship between zASM and frailty (average causal mediation effect in men: -0.096 {-0.159 to -0.050}; in women: -0.053 {-0.098 to -0.010}). For every one-point increase in zGS score, the relative risk of a one-point increase in frailty was reduced by 21% in men (e-0.238  = 0.788) and by 11% in women (e-0.113  = 0.893). CONCLUSIONS: In this study on Korean older adults, muscle mass did not have a direct effect on frailty but had an indirect effect through altered muscle function.

Discovery and Structure-Activity Relationships of Novel Template, Truncated 1'-Homologated Adenosine Derivatives as Pure Dual PPARγ/δ Modulators.

Following our report that A3 adenosine receptor (AR) antagonist 1 exhibited a polypharmacological profile as a dual modulator of peroxisome proliferator-activated receptor (PPAR)γ/δ, we discovered a new template, 1'-homologated adenosine analogues 4a-4t, as dual PPARγ/δ modulators without AR binding. Removal of binding affinity to A3AR was achieved by 1'-homologation, and PPARγ/δ dual modulation was derived from the structural similarity between the target nucleosides and PPAR modulator drug, rosiglitazone. All the final nucleosides were devoid of AR-binding affinity and exhibited high binding affinities to PPARγ/δ but lacked PPARα binding. 2-Cl derivatives exhibited dual receptor-binding affinity to PPARγ/δ, which was absent for the corresponding 2-H derivatives. 2-Propynyl substitution prevented PPARδ-binding affinity but preserved PPARγ affinity, indicating that the C2 position defines a pharmacophore for selective PPARγ ligand designs. PPARγ/δ dual modulators functioning as both PPARγ partial agonists and PPARδ antagonists promoted adiponectin production, suggesting their therapeutic potential against hypoadiponectinemia-associated cancer and metabolic diseases.

Expressional and functional analyses of epididymal SPINKs in mice.

Epididymal maturation is critical for acquisition of motility and fertilizing capacity by sperm. During epididymal transit, the surface of sperm undergoes prominent sequential changes through interactions with secreted proteins, including protease inhibitors. In the present study, we characterized three epididymis-specific SPINKs (serine protease inhibitors, Kazal-type): SPINK8, SPINK11, and SPINK12. We found that these epididymal SPINKs are expressed in an epididymal region-specific manner and their expression is developmentally regulated. Remarkably, cellular analyses revealed that SPINK8 and SPINK12 are transferred to the sperm. To investigate the in vivo properties of SPINK12, we analyzed knockout mice generated by CRISPR/Cas9-mediated genome editing. Loss of SPINK12 did not alter epididymal tubule structure or sperm phenotypes. Spink12 mutant mice exhibited normal fertility, suggesting that SPINK12 is functionally redundant in the epididymis.

Identification of target genes for spermatogenic cell-specific KRAB transcription factor ZFP819 in a male germ cell line.

BACKGROUND: Zfp819, a member of the Krüppel-associated box (KRAB) family, encodes a spermatogenic cell-specific transcription factor. Zfp819-overexpression induces apoptosis and inhibits proliferation in somatic cell lines. RESULTS: In the present study, we examined the cellular effects of Zfp819 in a male germ cell line (GC-2 cells). Overexpression of Zfp819 demonstrated an increase in the number of apoptotic cells, leading to inhibition of proliferation in GC-2 cells. We further investigated genes regulated by ZFP819 using microarray analysis and chromatin-immunoprecipitation combined with microarray analysis (ChIP-chip) in GC-2 cells. We identified 118 downregulated genes in Zfp819-overexpressing GC-2 cells using microarray analysis. ChIP-chip assay revealed that 1011 promoter sites (corresponding to 262 genes) were specifically enriched in GC-2 cells transfected with Zfp819. Two genes (trinucleotide repeat containing 6b and annexin A11) were commonly found when we compared the data between microarray and ChIP-chip analyses. Consistent with these results, Zfp819 overexpression significantly reduced the transcript levels of the two genes by binding to their promoter regions. Tissue distribution analysis indicated that both genes were predominantly expressed in testis. It has been reported that these two genes function in apoptosis. CONCLUSION: Collectively, our study provides inclusive information on germ cell-specific gene regulation by ZFP819, which is involved in apoptosis, to maintain the integrity of spermatogenesis.

Characterization of MAGEG2 with testis-specific expression in mice.

Male germ cell development is a well-defined process occurring in numerous seminiferous tubules of the testis. Uncovering testicular novel genes related to intrinsic regulation of spermatogenesis is essential for the understanding of spermatogenesis. In the present study, we investigated mouse Mageg2, which belongs to a group of melanoma-associated antigens (MAGEs). Mageg2 is transcribed in the testis specifically, and its expression level is increased at the pachytene spermatocyte stage, indicating that Mageg2 is expressed predominantly in germ cells. We generated an antibody against mouse MAGEG2 for further characterization at the protein level. Immunoblot analysis suggested that MAGEG2 has specific testicular expression and the expression primarily occurred in pachytene spermatocytes. Proteomic analyses demonstrated that mouse MAGEG2 binded to testicular germ cell-specific serine/threonine-protein kinase 31 (STK31) and heat shock protein 9 (HSPA9). Direct binding with both interaction partners was confirmed by co-immunoprecipitation. We found that STK31 and HSPA9 bind MAGEG2 directly but not with each other. Interestingly, MAGEG2 reduced the kinase activity of STK31. Our study suggests that mouse MAGEG2 has at least two functions, including chaperone activity related to HSPA9 and regulation of pachytene spermatocyte-specific kinase, STK31. Altogether, our results provide the first information about MAGEG2 at the transcript and protein levels and suggest its potential molecular functions.

TEX13 is a novel male germ cell-specific nuclear protein potentially involved in transcriptional repression.

The identification and characterization of male germ cell-specific genes is crucial to understanding the mechanisms of male germ cell development. In this study, we investigated the protein encoded by the novel mouse germ cell-specific gene testis-expressed gene 13 (Tex13). We found that TEX13 expression is testis- and germ cell-specific and is regulated in a stage-specific manner via translational repression. Immunostaining of testicular cells and sperm showed that TEX13 is localized in the nuclei of spermatogenic cells and the redundant nuclear envelope of mature sperm. Remarkably, we found that TEX13 possesses transcriptional repressor activity and that its overexpression in GC-2 cells altered the expression levels of 130 genes. Our results suggest that TEX13 has a potential role in transcriptional regulation during spermatogenesis.

Characterization of Mammalian ADAM2 and Its Absence from Human Sperm.

The members of the ADAM (a disintegrin and metalloprotease) family are membrane-anchored multi-domain proteins that play prominent roles in male reproduction. ADAM2, which was one of the first identified ADAMs, is the best studied ADAM in reproduction. In the male germ cells of mice, ADAM2 and other ADAMs form complexes that contribute to sperm-sperm adhesion, sperm-egg interactions, and the migration of sperm in the female reproductive tract. Here, we generated specific antibodies against mouse and human ADAM2, and investigated various features of ADAM2 in mice, monkeys and humans. We found that the cytoplasmic domain of ADAM2 might enable the differential association of this protein with other ADAMs in mice. Western blot analysis with the anti-human ADAM2 antibodies showed that ADAM2 is present in the testis and sperm of monkeys. Monkey ADAM2 was found to associate with chaperone proteins in testis. In humans, we identified ADAM2 as a 100-kDa protein in the testis, but failed to detect it in sperm. This is surprising given the results in mice and monkeys, but it is consistent with the failure of ADAM2 identification in the previous proteomic analyses of human sperm. These findings suggest that the reproductive functions of ADAM2 differ between humans and mice. Our protein analysis showed the presence of potential ADAM2 complexes involving yet-unknown proteins in human testis. Taken together, our results provide new information regarding the characteristics of ADAM2 in mammalian species, including humans.