Association between Early Spermarche and Suicide Attempts in Boys: the Korea Youth Risk Behavior Web-based Survey.

BACKGROUND: Puberty is a biologically and psychologically unstable period, and pubertal changes differ by sex. However, most previous studies on pubertal timing and suicide have focused on girls. This study investigated the association between early spermarche and suicide attempts in boys. METHODS: We analyzed a nationally representative sample of Korean adolescents (The Korea Youth Risk Behavior Web-Based Survey, KYRBS) that included approximately 35,000 boys annually from 2011 to 2015. Pubertal timing in boys was defined by spermarche. Complex sampling logistic regression analyses were performed to evaluate the odds ratios (ORs) for suicide attempts between the early and average spermarche groups. RESULTS: The ORs for suicide attempts in boys with early spermarche were significantly higher than those in boys with average spermarche after adjustment for age, perceived stress, depressive symptoms, and suicidal ideation. The ORs from 2011 to 2015 were as follows: 1.782 (P < 0.001), 1.490 (P = 0.002), 1.693 (P < 0.001), 1.541 (P = 0.001), and 1.393 (1.024-1.895; P = 0.035), respectively. CONCLUSION: These findings suggest that early pubertal timing is a risk factor for suicide attempts in Korean boys after adjustment for depressive symptoms, perceived stress, and suicidal ideation, which have been previously reported as risk factors for suicide attempts. Therefore, careful attention should be paid to the prevention of suicide in boys who experience early spermarche in Korea.

Increased intracellular Ca2+ concentrations prevent membrane localization of PH domains through the formation of Ca2+-phosphoinositides.

Insulin resistance, a key etiological factor in metabolic syndrome, is closely linked to ectopic lipid accumulation and increased intracellular Ca2+ concentrations in muscle and liver. However, the mechanism by which dysregulated intracellular Ca2+ homeostasis causes insulin resistance remains elusive. Here, we show that increased intracellular Ca2+ acts as a negative regulator of insulin signaling. Chronic intracellular Ca2+ overload in hepatocytes during obesity and hyperlipidemia attenuates the phosphorylation of protein kinase B (Akt) and its key downstream signaling molecules by inhibiting membrane localization of pleckstrin homology (PH) domains. Pharmacological approaches showed that elevated intracellular Ca2+ inhibits insulin-stimulated Akt phosphorylation and abrogates membrane localization of various PH domain proteins such as phospholipase Cδ and insulin receptor substrate 1, suggesting a common mechanism inhibiting the membrane targeting of PH domains. PH domain-lipid overlay assays confirmed that Ca2+ abolishes the binding of various PH domains to phosphoinositides (PIPs) with two adjacent phosphate groups, such as PI(3,4)P2, PI(4,5)P2, and PI(3,4,5)P3 Finally, thermodynamic analysis of the binding interaction showed that Ca2+-mediated inhibition of targeting PH domains to the membrane resulted from the tight binding of Ca2+ rather than PH domains to PIPs forming Ca2+-PIPs. Thus, Ca2+-PIPs prevent the recognition of PIPs by PH domains, potentially due to electrostatic repulsion between positively charged side chains in PH domains and the Ca2+-PIPs. Our findings provide a mechanistic link between intracellular Ca2+ dysregulation and Akt inactivation in insulin resistance.

The Mediating Effect of Depressive Symptoms on the Relationship between Adverse Childhood Experiences and Problematic Internet Use in Children and Adolescents.

The purpose of this study was to evaluate the mediating effect of depressive symptoms on the relationship between adverse childhood experiences (ACEs) and problematic internet use. The study participants were 180 students between the ages of 9 and 18 years. Path analysis was performed to measure the relationships among ACEs, depressive symptoms and problematic internet use. ACEs significantly affected depressive symptoms (standardized regression weight, 0.36; P < 0.01), and depressive symptoms also affected problematic internet use (standardized regression weight, 0.40; P < 0.01). We found that depressive symptoms had a significant mediating effect on the relationship between problematic internet use and ACEs. The management of depressive symptoms would be important to prevent problematic internet use in children and adolescents with ACEs.

Psychological Development during Medical School Clerkship: Relationship to Resilience.

OBJECTIVE: The authors investigated changes in medical students' defenses during clerkship and examined the effects of these changes on students' resilience. METHODS: Between 2012 and 2014, all year-2 preclinical students (N = 249) at Gyeongsang National University Medical School were asked to participate. Those who agreed to participate (N = 237) completed the Korean version of the Defense Style Questionnaire (K-DSQ) and the Connor-Davidson resilience scale-10 (CD-RISC-10). After clerkship, students who proceeded to year 4 in 2 years (n = 187 (93 females), aged 24-38 years (mean, 28.9 ± 2.8 years)) completed the K-DSQ, CD-RISC-10, and the Korean version of the Hospital Anxiety and Depression Scale (K-HADS) in September 2014, 2015, and 2016. RESULTS: The use of adaptive (W = 11,603.5, p < 0.001, r = 0.39) and self-inhibiting (W = 10,901.5, p < 0.001, r = 0.32) styles increased significantly after clerkship. A multiple linear regression analysis showed that changes in adaptive defense styles (B = 1.336, SE = 0.386, ß = 0.218, p = 0.001) during clerkship were significantly related to resilience after adjusting for age, sex, depression, and anxiety. CONCLUSIONS: Both positive personality development and maladaptive changes in defenses were evident. An increase in the adaptive defense style score was related to resilience.

Psychiatric Symptoms and Clinical Diagnosis in High School Students Exposed to the Sewol Ferry Disaster.

BACKGROUND: Two hundred and fifty 11th grade students and teachers from Danwon High School drowned, during a school trip, in the Sewol Ferry Disaster. The goal of this study was to investigate the experiences of the psychiatrists who volunteered and provided psychiatric services to the students at Danwon High School. METHODS: From the second day to the 138th day after the disaster, pro bono psychiatrists provided post-disaster interventions to the 10th and 12th-grade Danwon High School students who did not attend the trip. Officially, 167 psychiatrists conducted outreach in approximately 550 encounters. The study questionnaires were distributed retrospectively to psychiatric volunteers who conducted outreach at Danwon High School. We surveyed the pro bono psychiatrists about their experiences, including the students' chief complaints, psychiatric problems, clinical diagnoses, and psychiatrists' treatment recommendations. RESULTS: We reached 72 (43.1%) of the 167 volunteers, and they reported on 212 (38.6%) of the 550 encounters. The common chief complaints were mental health problems, companion problems, and family problems. The most frequent psychiatric symptoms were anxiety (76.89%), depressive mood (51.42%), and concentration difficulty (50.94%). The most frequent clinical diagnoses of the students were normal reaction (41.04%), acute stress disorder (24.53%), adjustment disorder (17.92%), anxiety disorders (9.43%), and posttraumatic stress disorder (6.60%). More than half of the students needed "additional counseling/therapy" (41.04%) or "referral to psychiatric treatment" (14.15%). CONCLUSION: During the acute aftermath of the Sewol Ferry Disaster, volunteer psychiatrists were able to provide services. These services included psychiatric assessments, crisis counseling, psychological first aid, and referrals for ongoing care. More than half of the students were perceived to have a psychiatric diagnosis, and a substantial proportion of students needed further treatment. Future research should focus on the short- and long-term effects of psychiatric interventions and the characterization of post-disaster mental health needs and service provision patterns.

The Role of NOX4 in Parkinson's Disease with Dementia.

The neuropathology of Parkinson's disease with dementia (PDD) has been reported to involve heterogeneous and various disease mechanisms. Alpha-synuclein (α-syn) and amyloid beta (Aß) pathology are associated with the cognitive status of PDD, and NADPH oxidase (NOX) is known to affect a variety of cognitive functions. We investigated the effects of NOX on cognitive impairment and on α-syn and Aß expression and aggregation in PDD. In the 6-hydroxydopamine (6-OHDA)-injected mouse model, cognitive and motor function, and the levels of α-syn, Aß, and oligomer A11 after inhibition of NOX4 expression in the hippocampal dentate gyrus (DG) were measured by the Morris water maze, novel object recognition, rotation, and rotarod tests, as well as immunoblotting and immunohistochemistry. After 6-OHDA administration, the death of nigrostriatal dopamine neurons and the expression of α-syn and NOX1 in the substantia nigra were increased, and phosphorylated α-syn, Aß, oligomer A11, and NOX4 were upregulated in the hippocampus. 6-OHDA dose-dependent cognitive impairment was observed, and the increased cognitive impairment, Aß expression, and oligomer A11 production in 6-OHDA-treated mice were suppressed by NOX4 knockdown in the hippocampal DG. Our results suggest that increased expression of NOX4 in the hippocampal DG in the 6-OHDA-treated mouse induces Aß expression and oligomer A11 production, thereby reducing cognitive function.

Effect of Inhibition of DNA Methylation Combined with Task-Specific Training on Chronic Stroke Recovery.

To develop new rehabilitation therapies for chronic stroke, this study examined the effectiveness of task-specific training (TST) and TST combined with DNA methyltransferase inhibitor in chronic stroke recovery. Eight weeks after photothrombotic stroke, 5-Aza-2'-deoxycytidine (5-Aza-dC) infusion was done on the contralesional cortex for four weeks, with and without TST. Functional recovery was assessed using the staircase test, the cylinder test, and the modified neurological severity score (mNSS). Axonal plasticity and expression of brain-derived neurotrophic factor (BDNF) were determined in the contralateral motor cortex. TST and TST combined with 5-Aza-dC significantly improved the skilled reaching ability in the staircase test and ameliorated mNSS scores and cylinder test performance. TST and TST with 5-Aza-dC significantly increased the crossing fibers from the contralesional red nucleus, reticular formation in medullar oblongata, and dorsolateral spinal cord. Mature BDNF was significantly upregulated by TST and TST combined with 5-Azd-dC. Functional recovery after chronic stroke may involve axonal plasticity and increased mature BDNF by modulating DNA methylation in the contralesional cortex. Our results suggest that combined therapy to enhance axonal plasticity based on TST and 5-Aza-dC constitutes a promising approach for promoting the recovery of function in the chronic stage of stroke.

A synthetic cryptochrome inhibitor induces anti-proliferative effects and increases chemosensitivity in human breast cancer cells.

Disruption of circadian rhythm is a major cause of breast cancer in humans. Cryptochrome (CRY), a circadian transcription factor, is a risk factor for initiation of breast cancer, and it is differentially expressed between normal and breast cancer tissues. Here, we evaluated the anti-proliferative and pro-apoptotic activity of KS15, a recently discovered small-molecule inhibitor of CRY, in human breast cancer cells. First, we investigated whether KS15 treatment could promote E-box-mediated transcription by inhibiting the activity of CRY in MCF-7 human breast cancer cells. Protein and mRNA levels of regulators of cell cycle and apoptosis, as well as core clock genes, were differentially modulated in response to KS15. Next, we investigated whether KS15 could inhibit proliferation and increase sensitivity to anti-tumor drugs in MCF-7 cells. We found that KS15 decreased the speed of cell growth and increased the chemosensitivity of MCF-7 cells to doxorubicin and tamoxifen, but had no effect on MCF-10A cells. These findings suggested that pharmacological inhibition of CRY by KS15 exerts an anti-proliferative effect and increases sensitivity to anti-tumor drugs in a specific type of breast cancer.

Allergic diseases, excessive Internet use and suicidal ideation in Korean adolescents.

OBJECTIVE: The aim of this study is to evaluate the relation between suicidal ideation, allergic diseases, and excessive Internet use in Korean youth using a national representative dataset. METHODS: Data from the Korean Youth Risk Behavior Web-Based Survey (KYRBWS), conducted by the Korean Centers for Disease Control and Prevention, were used in this study. Complex sample logistic regression and structural equation modeling were performed to define the relation between suicidal ideation, allergic disease and excessive Internet use. RESULTS: A total of 73,238 students participated in this survey. In Korea, 19.3% of adolescents had suicidal ideation in the previous year. Asthma (OR=1.23, 95% CI=1.15-1.32, p<0.01) and allergic rhinitis (OR=1.17, 95% CI=1.11-1.22, p<0.01) were identified as risk factors for suicidal ideation after adjusting for school and family factors. Structural equation modeling showed that excessive Internet use interacted with the association between allergic diseases and suicidal ideation. CONCLUSION: Allergy problems could positively affect suicidal ideation in Korean adolescents. Excessive Internet use could be a mediating factor between allergic disease and suicidal ideation.

Association analysis of PDE4B polymorphisms with schizophrenia and smooth pursuit eye movement abnormality in a Korean population.

Schizophrenia is a debilitating mental disorder with a high heritability rate. Located on chromosome 1p31.3, the human cAMP-specific 3',5'-cyclic phosphodiesterase 4B (PDE4B) gene has been considered as an important candidate gene for the risk of schizophrenia. Several genetic association studies reported the association between PDE4B polymorphisms and the risk of schizophrenia in Caucasian, African American, Indian, and Japanese populations. The aim of this study is to examine the association of PDE4B variations with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. A case-control association analysis was carried out by comparing the genotype distribution of eight PDE4B polymorphisms between 457 schizophrenia patients and 386 normal healthy subjects. Differences in the frequency distribution of PDE4B single nucleotide polymorphisms (SNPs) and haplotypes were analyzed by logistic regression analyses controlling for age as a covariate. Statistical analyses revealed nominal significant associations of rs1040716, rs472952, rs1321177, and rs2144719 with the risk of schizophrenia (p = 0.02~0.05). The rs11208756 polymorphism showed a nominal significant association with SPEM abnormality (p = 0.05). In a meta-analysis with Japanese and Korean populations, three SNPs (rs472952, rs1040716, and rs2180335) revealed significant associations with schizophrenia (meta-p value = 0.0038~0.019). Our results support previously reported association of PDE4B variations with schizophrenia in other populations. The findings in this study add a new evidence for the involvement of PDE4B gene in schizophrenia etiology.

Usefulness of the combined application of the Mood Disorder Questionnaire and Bipolar Spectrum Diagnostic Scale in screening for bipolar disorder.

OBJECTIVE: This study aimed to examine whether combined application of the Mood Disorder Questionnaire (MDQ) and Bipolar Spectrum Diagnostic Scale (BSDS) is more effective than exclusive application of either tool in screening for bipolar disorder (BD). METHOD: The MDQ and BSDS were completed by a total of 113 patients diagnosed with BD and major depressive disorder who were experiencing a current major depressive episode. The initial diagnosis of the subject was confirmed during a 1-year follow-up period. When each MDQ and BSDS optimal cutoff score was calculated, a modified scoring method for the MDQ that considered only one item was used to increase its performance in this population. The following three combinations of the cutoff scores for the two tools were used to screen for BD: (A) The score on either the MDQ or BSDS was greater than or equal to the cutoff score; (B) the scores on both the MDQ and BSDS were greater than or equal to the cutoff score; and (C) Reducing either cutoff score by 1 point resulted in the MDQ and BSDS scores being greater than or equal to the cutoff score. The sensitivity, specificity, positive predictive value, and negative predictive value of the three methods, the MDQ, and the BSDS were compared for screening BD. RESULTS: The sensitivity and specificity of the MDQ were 0.741 and 0.844, respectively, and those for the BSDS were 0.731 and 0.742, respectively. These indicators for the combined application of the MDQ and BSDS were as follows, respectively: method A 0.901 and 0.688, method B 0.580 and 0.875, and method C 0.691 and 0.844. Method A was superior to using one measure alone as well as to methods B and C with regard to sensitivity and negative predictive values. Method A also showed a higher sensitivity for BD subtypes than did the individual tools. Compared with the use of individual instruments, method A showed a similar positive predictive value. CONCLUSION: This study suggests that combined use of the MDQ and BSDS is more effective than the individual use of either of these measures in screening for BD. The data also showed that when both tools were used, the most effective interpretation of the results in terms of screening for BD was achieved when positive scores were defined as those that were equal to or greater than the cutoff for the MDQ or BSDS.

Functional Analysis of CXCR3 Splicing Variants and Their Ligands Using NanoBiT-Based Molecular Interaction Assays.

CXCR3 regulates leukocyte trafficking, maturation, and various pathophysiological conditions. Alternative splicing generates three CXCR3 isoforms in humans. Previous studies investigated the roles of CXCR3 isoforms, and some biochemical data are not correlated with biological relevance analyses. RT-PCR analyses indicate that most cells express all three splicing variants, suggesting that they may mutually affect the chemokine binding and cellular responses of other splicing variants. Here, we performed an integrative analysis of the functional relations among CXCR3 splicing variants and their chemokine-dependent signaling using NanoBiT live cell protein interaction assays. The results indicated that the CXCR3 N-terminal region affected cell surface expression levels and ligand-dependent activation. CXCR3A was efficiently expressed in the plasma membrane and responded to I-TAC, IP-10, and MIG chemokines. By contrast, CXCR3B had low plasma membrane expression and mediated I-TAC-stimulated cellular responses. CXCR3Alt was rarely expressed on the cell surface and did not mediate any cell responses to the tested chemokines; however, CXCR3Alt negatively affected the plasma membrane expression of CXCR3A and CXCR3B and their chemokine-stimulated cellular responses. Jurkat cells express endogenous CXCR3, and exogenous CXCR3A expression enhanced chemotactic activity in response to I-TAC, IP-10, and MIG. By contrast, exogenous expression of CXCR3B and CXCR3Alt eliminated or reduced the CXCR3A-induced chemotactic activity. The PF-4 chemokine did not activate any CXCR3-mediated cellular responses. NanoBiT technology are useful to integrative studies of CXCR3-mediated cell signaling, and expand our knowledge of the cellular responses mediated by molecular interactions among the splicing variants, including cell surface expression, ligand-dependent receptor activation, and chemotaxis.

The N-terminus of CXCR4 splice variants determines expression and functional properties.

C-X-C motif chemokine ligand 12(CXCL12) is an essential chemokine for organ development and homeostasis in multiple tissues. Its receptor, C-X-C chemokine receptor type 4(CXCR4), is expressed on the surface of target cells. The chemokine and receptor are expressed almost ubiquitously in human tissues and cells throughout life, and abnormal expression of CXCL12 and CXCR4 is observed in pathological conditions, such as inflammation and cancer. CXCR4 is reportedly translated into five splicing variants of different lengths, which each have different amino acids in the N-terminus. As the N-terminus is the first recognition site for chemokines, CXCR4 variants may respond differently to CXCL12. Despite these differences, the molecular and functional properties of CXCR4 variants have not been thoroughly described or compared. Here, we explored the expression of CXCR4 variants in cell lines and analyzed their roles in cellular responses using biochemical approaches. RT-PCR revealed that most cell lines express more than one CXCR4 variant. When expressed in HEK293 cells, the CXCR4 variants differed in protein expression efficiency and cell surface localization. Although variant 2 demonstrated the strongest expression and cell surface localization, variants 1, 3, and 5 also mediated chemokine signaling and induced cellular responses. Our results demonstrate that the N-terminal sequences of each CXCR4 variant determine the expression of the receptor and affect ligand recognition. Functional analyses revealed that CXCR4 variants may also affect each other or interact during CXCL12-stimulated cellular responses. Altogether, our results suggest that CXCR4 variants may have distinct functional roles that warrant additional investigation and could contribute to future development of novel drug interventions.

Neurokinin-2 receptor negatively modulates substance P responses by forming complex with Neurokinin-1 receptor.

BACKGROUND: Tachykinins and their cognate receptors, neurokinin receptors (NKs) including NK1, NK2, and NK3 play vital roles in regulating various physiological processes including neurotransmission, nociception, inflammation, smooth muscle contractility, and stimulation of endocrine and exocrine gland secretion. Their abnormal expression has been reported to be associated with neurological disorders, inflammation, and cancer. Even though NKs are expressed in the same cells with their expression being inversely correlated in some conditions, there is no direct evidence to prove their interaction. Understanding the functional crosstalk between NKs in mediated downstream signaling and cellular responses may elucidate the roles of each receptor in pathophysiology. RESULTS: In this study, we showed that NKs were co-expressed in some cells. However, different from NK3, which only forms homodimerization, we demonstrated a direct interaction between NK1 and NK2 at the protein level using co-immunoprecipitation and NanoBiT-based protein interaction analysis. Through heterodimerization, NK2 downregulated substance P-stimulated NK1 signals, such as intracellular Ca2+ mobilization and ERK phosphorylation, by enhancing ß-arrestin recruitment, even at the ligand concentration that could not activate NK2 itself or in the presence of NK1 specific antagonist, aprepitant. In A549 cells with receptors deleted and reconstituted, NK2 exerted a negative effect on substance P/NK1-mediated cell migration. CONCLUSION: Our study has provided the first direct evidence of an interaction between NK1 and NK2, which highlights the functional relevance of their heterodimerization in cellular responses. Our findings demonstrated that through dimerization, NK2 exerts negative effects on downstream signaling and cellular response mediated by NK1. Moreover, this study has significant implications for understanding the complexity of GPCR dimerization and its effect on downstream signaling and cellular responses. Given the important roles of tachykinins and NKs in pathophysiology, these insights may provide clues for developing NKs-targeting drugs.

Association Between Depressed Mood Changes and Physical Activity Among Adolescents Post COVID-19 Pandemic.

Objectives: Following the coronavirus disease 2019 (COVID-19) pandemic, adolescents have experienced decreased physical activity and a decline in mental health. This study analyzed the association between changes in depressed mood after the COVID-19 pandemic and physical activity among adolescents. Methods: The analysis was based on the results of the 17th Youth Health Behavior Online Survey conducted in 2021, which included 54848 middle and high school students in South Korea. Information on physical activity included low-intensity physical activity lasting >60 min/day, high-intensity physical activity, and strength training exercises. A logistic regression analysis was performed to evaluate the association between physical activity and changes in depression after the COVID-19 pandemic. Results: After adjusting for sociodemographic characteristics and previous depression, adolescents who performed strength training exercises more than once per week had a 0.95-fold lower risk (odds ratio [OR]=0.948, 95% confidence interval [CI]=0.905-0.994, p= 0.027) of increasing depression after the COVID-19 pandemic, while the risk of decreasing depression increased by 1.22-fold (OR=1.215, 95% CI=1.131-1.305, p<0.001). The results were not significant for low-intensity physical activity for >60 min/day and high-intensity physical activity. Conclusion: Strength-training exercises are significantly associated with the prevention of depression among adolescents following the COVID-19 pandemic.

Dietary Carotene Intake and Suicidal Ideation in Korean Females: Analysis of Data From the Korea National Health and Nutrition Examination Survey (2012, 2013, and 2015).

OBJECTIVE: The suicide rate in Korea was the highest among countries in the Organisation for Economic Co-operation and Development in 2019. In a previous study, higher intake of vegetables and fruits was associated with a lower risk of suicidal ideation, and carotene-rich fruits and vegetables lowered the risk of depression. This study aimed to examine the direct relationship between carotene intake and suicidal ideation, adjusting for the effect on depression. METHODS: This study used data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted in 2012, 2013, and 2015. Carotene intake was assessed through a food intake frequency survey with a 24-hour recall. Suicidal ideation and depression were assessed using the mental health section of the KNHANES. We applied logistic regression to assess the relationship between carotene intake and suicidal ideation, adjusting for potential confounders. RESULTS: A total of 5,480 females aged 19-64 years were included in this study. Carotene intake was significantly lower in the suicidal ideation group (3,034.5±1,756.4 µg/day) than in the nonsuicidal ideation group (3,225.4±1,795.1 µg/day) (p=0.015). We found a significant inverse association between carotene intake and the risk of suicidal ideation after adjusting for potential confounders (odds ratio=0.934, 95% confidence interval=0.873-0.999). CONCLUSION: These results suggest that carotene intake may be inversely associated with the risk of suicidal ideation. Our findings may inform the development of new nutritional interventions to prevent increases in the risk of suicide worldwide.

Analysis of CCR2 splice variant expression patterns and functional properties.

BACKGROUND: C-C motif chemokine receptor 2 (CCR2), the main receptor for monocyte chemoattractant protein-1 (MCP-1), is expressed on immune cells, including monocytes, macrophages, and activated T cells, and mediates cell migration toward MCP-1 in inflammation-related diseases. The CCR2 gene encodes two isoforms: CCR2A and CCR2B. The CCR2B open reading frame is localized in a single exon, similar to other chemokine receptors, and CCR2A and CCR2B feature different amino acid sequences in their C-terminal intracellular loops due to alternative splicing. Most biochemical studies on CCR2-related cellular responses in the immune system have focused on CCR2B, with few reports focused on CCR2A. Understanding the functional properties of CCR2A in cellular responses may elucidate the roles played by MCP-1 and CCR2 in pathophysiological responses. RESULTS: CCR2 gene expression analysis in several cell types revealed that most adherent cells only expressed CCR2A, whereas CCR2B expression was dominant in monocytic cells. The C-terminal Helix 8 region of CCR2A contains few basic amino acids, which may be unfavorable for cell surface localization, as confirmed with the HiBiT assay. CCR2B contains many C-terminal Ser/Thr residues, similar to other chemokine receptors, which may be phosphorylated by G protein-coupled receptor kinases (GRKs) to promote ß-arrestin recruitment and subsequent endocytosis. By contrast, CCR2A contains few C-terminal Ser/Thr residues, which are unlikely to be phosphorylated by GRKs. CCR2A localized on the cell surface is resistant to internalization, despite the interaction between Gß and GRKs induced by ligand binding with CCR2A. CCR2A induced cellular responses at a relatively higher degree than CCR2B, although both receptors mediated signaling events through Gαq and Gαi. HeLa cells lacking CCR2A showed slowed growth compared with parent cells, regardless of MCP-1 stimulation, and their chemotactic activity toward MCP-1, in addition to basal motility, was significantly impaired. CONCLUSION: MCP-1 and CCR2 may play pivotal roles in cancer progression by recruiting macrophages into cancer tissue. This study demonstrates that CCR2A but not CCR2B is expressed in solid cancer-derived cells. CCR2A is resistant to internalization by ß-arrestin due to a distinct C-terminal region from CCR2B, which enhances MCP-1-stimulated responses, indicating that CCR2A may play essential roles in solid cancer progression.

Externalized phosphatidylinositides on apoptotic cells are eat-me signals recognized by CD14.

Apoptotic cells are rapidly engulfed and removed by phagocytes after displaying cell surface eat-me signals. Among many phospholipids, only phosphatidylserine (PS) is known to act as an eat-me signal on apoptotic cells. Using unbiased proteomics, we identified externalized phosphatidylinositides (PIPs) as apoptotic eat-me signals recognized by CD14+ phagocytes. Exofacial PIPs on the surfaces of early and late-apoptotic cells were observed in patches and blebs using anti-PI(3,4,5)P3 antibody, AKT- and PLCδ PH-domains, and CD14 protein. Phagocytosis of apoptotic cells was blocked either by masking exofacial PIPs or by CD14 knockout in phagocytes. We further confirmed that exofacial PIP+ thymocytes increased dramatically after in vivo irradiation and that exofacial PIP+ cells represented more significant populations in tissues of Cd14-/- than WT mice, especially after induction of apoptosis. Our findings reveal exofacial PIPs to be previously unknown cell death signals recognized by CD14+ phagocytes.

Lack of association of the RTN4R genetic variations with risk of schizophrenia and SPEM abnormality in a Korean population.

This study examined the association of the reticulon 4 receptor (RTN4R) gene with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Although we failed to provide convincing evidence that RTN4R is associated with schizophrenia development and SPEM impairment, our findings may be useful for further genetic studies.

Spinal cord injury markedly altered protein expression patterns in the affected rat urinary bladder during healing stages.

The influence of spinal cord injury (SCI) on protein expression in the rat urinary bladder was assessed by proteomic analysis at different time intervals post-injury. After contusion SCI between T9 and T10, bladder tissues were processed by 2-DE and MALDI-TOF/MS at 6 hr to 28 days after SCI to identify proteins involved in the healing process of SCI-induced neurogenic bladder. Approximately 1,000 spots from the bladder of SCI and sham groups were visualized and identified. At one day after SCI, the expression levels of three protein were increased, and seven spots were down-regulated, including heat shock protein 27 (Hsp27) and heat shock protein 20 (Hsp20). Fifteen spots such as S100-A11 were differentially expressed seven days post-injury, and seven proteins including transgelin had altered expression patterns 28 days after injury. Of the proteins with altered expression levels, transgelin, S100-A11, Hsp27 and Hsp20 were continuously and variably expressed throughout the entire post-SCI recovery of the bladder. The identified proteins at each time point belong to eight functional categories. The altered expression patterns identified by 2-DE of transgelin and S100-A11 were verified by Western blot. Transgelin and protein S100-A11 may be candidates for protein biomarkers in the bladder healing process after SCI.