[This corrects the article DOI: 10.7150/thno.82898.].

Chitinase-3-like protein 1 (CHI3L1) is a secreted glycoprotein that mediates inflammation, macrophage polarization, apoptosis, and carcinogenesis. The expression of CHI3L1 is strongly upregulated by various inflammatory and immunological diseases, including several cancers, Alzheimer’s disease, and atherosclerosis. Several studies have shown that CHI3L1 can be considered as a marker of disease diagnosis, prognosis, disease activity, and severity. In addition, the proinflammatory action of CHI3L1 may be mediated via responses to various proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, interleukin-6, and interferon-γ. Therefore, CHI3L1 may contribute to a vast array of inflammatory diseases. However, its pathophysiological and pharmacological roles in the development of inflammatory diseases remain unclear. In this article, we review recent findings regarding the roles of CHI3L1 in the development of inflammatory diseases and suggest therapeutic approaches that target CHI3L1.

The relationship between schizophrenia (SCZ) and cancer development remains controversial. Based on the disease-gene association platform, it has been revealed that tumor necrosis factor receptor (TNFR) could be an important mediatory factor in both cancer and SCZ development. TNF-α also increases the expression of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) in the development of SCZ and tumor, but the role of TNFR in mediating the association between the two diseases remains unclear. We studied the vital roles of TNFR2 in the progression of tumor and SCZ-like behavior using A549 lung cancer cell xenografted TNFR2 knockout mice. TNFR2 knockout mice showed significantly decreased tumor size and weight as well as schizophrenia-like behaviors compared to wild-type mice. Consistent with the reduced tumor growth and SCZ-like behaviors, the levels of TrkB and BDNF expression were significantly decreased in the lung tumor tissues and pre-frontal cortex of TNFR2 knockout mice. However, intravenous injection of BDNF (160 μg/kg) to TNFR2 knockout mice for 4 weeks increased tumor growth and SCZ-like behaviors as well as TrkB expression. In in vitro study, significantly decreased cell growth and expression of TrkB and BDNF by siTNFR2 transfection were found in A549 lung cancer cells. However, the addition of BDNF (100 ng/ml) into TNFR2 siRNA transfected A549 lung cancer cells recovered cell growth and the expression of TrkB. These results suggest that TNFR2 could be an important factor in mediating the comorbidity between lung tumor growth and SCZ development through increased TrkB-dependent BDNF levels.

Interleukin-32γ (IL-32γ) has diverse functions in various malignancies. In this study, we investigated the role of IL-32γ in autophagy induction in liver cancer cells and delineated the underlying mechanisms. We found that the increased IL-32γ expression inhibited the growth, cell cycle progression, and migration of HepG2 and Hep3B cell lines; it also decreased the expression of related proteins. Furthermore, the IL-32γ overexpression induced autophagy, as indicated by the number of puncta, the expression of LC3, and the expression of autophagy-related markers. The expression levels of LAMP1, a protein essential for autophagosome formation, and colocalization with LC3 also increased. Big data analysis revealed that the expression of MET, a well-known target of autophagy, and the expression of mTOR and mTOR-related proteins were decreased by the IL-32γ overexpression. The combination treatment of MET inhibitor, cabozantinib (2 µM), and IL-32γ overexpression further increased the number of puncta, the colocalization of LC3 and LAMP1, and the expression of autophagy-related proteins. In vivo, liver tumor growth was suppressed in the IL-32γ-overexpressing mouse model, and autophagy induction was confirmed by the increased expression of LC3 and LAMP1 and the decreased expression of autophagy pathway markers (MET and mTOR). Autophagy was also decreased in the liver tumor sample of human patients. ROC curve and spearman analysis revealed that the expression levels of LC3 and IL-32γ were significantly correlated in human tumor serum and tissues. Therefore, IL-32γ overexpression induced autophagy in liver tumors through the suppression of MET and mTOR pathways critical for tumor growth inhibition.

Primary cilium is an important hub for cell signaling and dysregulation of primary cilia assembly and disassembly is associated with the development of cancer and chemotherapeutic drug resistance, as well as the genetic disorders collectively known as ciliopathy. β-catenin plays a major role in canonical Wnt signaling; however, its association with primary cilia has only recently been highlighted in reports of β-catenin-mediated primary ciliogenesis. In this study, we found that β-catenin p-S47 was localized to the Golgi apparatus and the nucleus, and the amount of β-catenin p-S47 at these locations was significantly higher during primary ciliogenesis compared with asynchronous cell growth conditions. In addition, the novel β-catenin-binding motor proteins KIF11 and KIFC3 were shown to have a lower binding affinity in β-catenin S47A than in β-catenin wild-type. Knockdown of KIF11 or KIFC3 resulted in primary cilia deficiency and increased β-catenin p-S47 levels in the Golgi apparatus and were accompanied by a decrease in β-catenin p-S47 at the centrosome. The accumulation of β-catenin p-S47 in the nucleus was increased during primary ciliogenesis along with β-catenin-dependent transcriptional activity. The collective findings indicate the existence of a novel mechanism of primary ciliogenesis involving KIF11-/KIFC3-associated β-catenin p-S47 in the Golgi apparatus and β-catenin p-S47 transcriptional activity in the nucleus. This study revealed a new mechanism for the study of ciliopathies, cancer, and chemotherapeutic drug resistance caused by primary ciliogenesis dysregulation and provides new targets for drug development to treat these diseases.

CHI3L1 is closely related to the molecular mechanisms of cancer cell migration, growth, and death. According to recent research, autophagy regulates tumor growth during various stages of cancer development. This study examined the association between CHI3L1 and autophagy in human lung cancer cells. In CHI3L1-overexpressing lung cancer cells, the expression of LC3, an autophagosome marker, and the accumulation of LC3 puncta increased. In contrast, CHI3L1 depletion in lung cancer cells decreased the formation of autophagosomes. Additionally, CHI3L1 overexpression promoted the formation of autophagosomes in various cancer cell lines: it also increased the co-localization of LC3 and the lysosome marker protein LAMP-1, indicating an increase in the production of autolysosomes. In mechanism study, CHI3L1 promotes autophagy via activation of JNK signaling. JNK may be crucial for CHI3L1-induced autophagy since pretreatment with the JNK inhibitor reduced the autophagic effect. Consistent with the in vitro model, the expression of autophagy-related proteins was downregulated in the tumor tissues of CHI3L1-knockout mice. Furthermore, the expression of autophagy-related proteins and CHI3L1 increased in lung cancer tissues compared with normal lung tissues. These findings show that CHI3L1-induced autophagy is triggered by JNK signals and that CHI3L1-induced autophagy could be a novel therapeutic approach to lung cancer.

Chitinase-3-like protein 1 (CHI3L1), which is secreted by immune and inflammatory cells, is associated with several inflammatory diseases. However, the basic cellular pathophysiological functions of CHI3L1 are not well characterized. To investigate the novel pathophysiological function of CHI3L1, we performed LC-MS/MS analysis of cells transfected with Myc-vector and Myc-CHI3L1. We analyzed the changes in the protein distribution in Myc-CHI3L1 transfected-cells, and identified 451 differentially expressed proteins (DEPs) compared with Myc-vector-transfected-cells. The biological function of the 451 DEPs was analyzed and it was found that the proteins with endoplasmic reticulum (ER)-associated function were much more highly expressed in CHI3L1-overexpressing cells. We then compared and analyzed the effect of CHI3L1 on the ER chaperon levels in normal lung cells and cancer cells. We identified that CHI3L1 is localized in the ER. In normal cells, the depletion of CHI3L1 did not induce ER stress. However, the depletion of CHI3L1 induces ER stress and eventually activates the unfolded protein response, especially the activation of Protein kinase R-like endoplasmic reticulum kinase (PERK), which regulates protein synthesis in cancer cells. CHI3L1 may not affect ER stress owing to the lack of misfolded proteins in normal cells, but instead activate ER stress as a defense mechanism only in cancer cells. Under ER stress conditions induced by the application of thapsigargin, the depletion of CHI3L1 induces ER stress through the upregulation of PERK and PERK downstream factors (eIF2α and ATF4) in both normal and cancer cells. However, these signaling activations occur more often in cancer cells than in normal cells. The expression of Grp78 and PERK in the tissues of patients with lung cancer was higher compared with healthy tissues. It is well known that ER stress-mediated PERK-eIF2α-ATF4 signaling activation causes apoptotic cell death. ER stress-mediated apoptosis induced by the depletion of CHI3L1 occurs in cancer cells, but rarely occurs in normal cells. Consistent with results from the in vitro model, ER stress-mediated apoptosis was greatly increased during tumor growth and in the lung metastatic tissue of CHI3L1-knockout (KO) mice. The analysis of "big data" identified superoxide dismutase-1 (SOD1) as a novel target of CHI3L1 and interacted with CHI3L1. The depletion of CHI3L1 increased SOD1 expression, resulting in ER stress. Furthermore, the depletion of SOD1 reduced the expression of ER chaperones and ER-mediated apoptotic marker proteins, as well as apoptotic cell death induced by the depletion of CHI3L1 in in vivo and in vitro models. These results suggest that the depletion of CHI3L1 increases ER stress-mediated apoptotic cell death through SOD1 expression, and subsequently inhibits lung metastasis.

Sepsis is a life-threatening disease with limited treatment options, and the inflammatory process represents an important factor affecting its progression. Many studies have demonstrated the critical roles of signal transducer and activator of transcription 3 (STAT3) in sepsis pathophysiology and pro-inflammatory responses. Inhibition of STAT3 activity may therefore represent a promising treatment option for sepsis. We here used a mouse model to demonstrate that (E)-2-methoxy-4-(3-(4-methoxyphenyl)prop-1-en-1-yl)phenol (MMPP) treatment prevented the liver sepsis-related mortality induced by 30 mg/kg lipopolysaccharide (LPS) treatment and reduced LPS-induced increase in alanine transaminase, aspartate transaminase, and lactate dehydrogenase levels, all of which are markers of liver sepsis progression. These recovery effects were associated with decreased LPS-induced STAT3, p65, and JAK1 phosphorylation and proinflammatory cytokine (interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha) level; expression of cyclooxygenase-2 and induced nitric oxide synthase were also reduced by MMPP. In an in vitro study using the normal liver cell line THLE-2, MMPP treatment prevented the LPS-induced increase of STAT3, p65, and JAK1 phosphorylation and inflammatory protein expression in a dose-dependent manner, and this effect was enhanced by combination treatment with MMPP and STAT3 inhibitor. The results clearly indicate that MMPP treatment prevents LPS-induced mortality by inhibiting the inflammatory response via STAT3 activity inhibition. Thus, MMPP represents a novel agent for alleviating LPS-induced liver sepsis.

Dear Editor, Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease that is difficult to treat despite the discovery of various disease targets and development of therapeutics. Previous clinical studies have shown that chitinase 3-like protein 1 (CHI3L1), also known as YKL-40, is associated with the onset and severity of AD.1-3 Recently, CHI3L1 has attracted attention as a new therapeutic target for treating various diseases, including cancer and autoimmune diseases.4 Our gene-disease network analysis also showed CHI3L1 is associated with various diseases, including inflammatory diseases (Figure S1). However, the role of CHI3L1 in AD pathogenesis is not well-understood. Previously, we provided the first direct evidence that inhibition of CHI3L1 by K284-6111, a novel CHI3L1 inhibitor, ameliorates AD-like skin inflammation.5 Here, we further investigated the role of CHI3L1 in AD pathogenesis and its underlying mechanism using CHI3L1 knockout (KO) mice and a CHI3L1-blocking antibody (CHI3L1-Ab), and based on outcomes, propose that a CHI3L1-targeted therapeutic strategy can be used to treat AD. To determine if CHI3L1 plays a role in AD pathogenesis, CH3L1-KO and wild-type (WT) mice were treated with phthalic anhydride (PA) to induce AD-like skin inflammation. WT mice displayed elevated CHI3L1 levels in the epidermal/dermal layers, particularly in epidermal keratinocytes, and blood serum, as well as typical AD-like symptoms such as erythema, edema, hyperkeratosis and epidermal thickening. In comparison, CHI3L1-KO mice showed significantly reduced symptoms and abrogated CHI3L1 levels (Figure 1). In addition, PA-induced pro-inflammatory marker protein (cyclooxygenase-2 and inducible nitric oxide synthase) expression, inflammatory immune cell infiltration, inflammatory cytokine and chemokine (interleukin [IL]-1β, IL-4, IL-6, IL-13, thymic stromal lymphoprotein [TSLP] and C-C motif chemokine 22 [CCL22]) and IgE and histamine levels were decreased in the skin tissue or serum compared to those in WT mice (Figure S2). Moreover, expression of genes encoding inflammatory cytokines and chemokines induced by treatment with a mixture of tumour necrosis factor (TNF)-α and interferon (IFN)-γ, an inflammatory stimulant that induces AD-like features, was inhibited by CHI3L1 knockdown, whereas it was up-regulated by CHI3L1 overexpression in HaCaT cells (Figure S3). Taken together, these findings indicate that CHI3L1 greatly contributes to the AD pathogenesis. To explore the underlying mechanism of CHI3L1 in AD pathogenesis, we performed gene-network analysis using Humanbase, an interactive platform of data-driven predictions of gene regulation and interaction, which showed that CHI3L1 is linked to numerous genes of interest, including integrin beta2 (ITGB2) (Figure 2A). Integrins are transmembrane adhesion receptors with important roles in biological and pathological processes.6 Previous studies have shown that integrin alpha (ITGA) is overexpressed in atopic skin,7 and CHI3L1-mediated biological and pathological effects are through interactions with integrins.8 To determine the association between CHI3L1 and integrins including ITGB2, ITGA2, ITGA5 and ITGA6, we compared the mRNA expression levels of these integrins in the skin of the PA-induced AD model. Expression of all tested integrins increased in WT mice but decreased in CHI3L1-KO mice; particularly, ITGA5 expressions were significantly down-regulated by CHI3L1-KO (Figure 2B,C). Additionally, gene silencing and overexpression experiments in HaCaT cells demonstrated that ITGA5 expression was more affected by CHI3L1 compared to ITGA6 (Figure 2D,E). Differences in protein expression of ITGA5 were further confirmed in TNF-α/IFN-γ-treated HaCaT cells (Figure 2F) and skin tissues (Figure 2G). We further analysed the gene expression levels of pro-inflammatory mediators after knocking down ITGA5 expression in TNF-α/IFN-γ-treated HaCaT cells and found that the mRNA expressions of IL-1β, IL-6, TSLP and CCL22 were significantly decreased (Figure 2H). Notably, transcription factor prediction analysis showed that ITGA5 contains 13 putative nuclear factor (NF)-κB binding sites (Figure S4A). Interestingly, ITGA5 expression was inhibited by not only NF-κB p65 siRNA in TNF-α/IFN-γ-treated HaCaT cells (Figure S4B), but also in CHI3L1-overexpressing cells treated with an NF-κB inhibitor (Figure S4C), indicating that NF-κB is a key transcription factor regulating ITGA5 expression. As NF-κB is a critical regulator in AD,9 and CHI3L1 is known to bind to the RAGE (receptor for advanced glycation end-products) receptor to contribute to NF-κB activation, we investigated whether CHI3L1 modulates NF-κB signaling.10 CHI3L1 overexpression promoted NF-κB signaling activation in resting and TNF-α/IFN-γ-treated HaCaT cells (Figure S5A,B). In contrast, CHI3L1 knockdown reduced both TNF-α/IFN-γ-induced phosphorylation of IκBα and nuclear translocation of p50/p65 (Figure S5C,D). In addition, CHI3L1 knockdown together with the NF-κB inhibitor synergistically inhibited IL-1β, IL-6, TSLP and CCL22 production (Figure S5E). Notably, PA-induced NF-κB activation in the skin tissues decreased in CHI3L1-KO mice compared to in WT mice (Figure S5F,G). These results suggest that CHI3L1 induces inflammatory responses by activating NF-κB signaling, which may lead to AD-related skin inflammation. Collectively, our findings suggest that CHI3L1-related AD pathogenesis is associated with the regulation of the NF-κB/ITGA5 axis. After confirming that CHI3L1 regulates AD-related skin inflammation, we examined the therapeutic effect of CHI3L1-antibody (Ab). Administration of a CHI3L1-Ab alleviated PA-induced AD development and the inflammatory response and suppressed the production of CHI3L1 and ITGA5 and activation of NF-κB (Figure 3A–D). Furthermore, the analysis of the reconstructed human skin (RHS) tissue AD model confirmed that CHI3L1-Ab treatment reduced skin inflammation by inhibiting the CHI3L1/NF-κB/ITGA5 axis (Figure 3E–I). Additionally, we demonstrated that ITGA5-Ab treatment reduced epidermal thickness in the same RHS AD model (Figure S6). Finally, we found that the serum levels of CHI3L1, ITGA5 and other AD biomarkers were significantly increased in sera from patients with AD (Figure 4A,B [left] and Figure S7A). Receiver operating characteristic curve analysis indicated that CHI3L1 and ITGA5 are more suitable diagnostic markers for AD compared to other biomarkers (Figure 4A,B [right] and Figure S7B). Additionally, Spearman's correlation analysis showed that serum level of CHI3L1 significantly correlated with the serum level of ITGA5 (Figure 4C). These results suggest that CHI3L1 and ITGA5 are potent diagnostic and prognostic biomarkers for AD. In conclusion, CHI3L1 mediates AD-like skin inflammation by regulating NF-κB-dependent ITGA5 expression. Furthermore, the inhibition of CHI3L1 by CHI3L1-Ab suppresses AD-like symptoms and inflammatory responses by regulating CHI3L1, the NF-κB/ITGA5 axis. Our findings provide experimental rationale for developing therapeutic strategies for AD by targeting CHI3L1. This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean government (MSIP) (grant numbers: MRC, 2017R1A5A2015541 and NRF-2020R1F1A1073308). The authors declare that they have no competing interests. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Our previous big data analyses reported a strong association between CHI3L1 expression and lung tumor development. In this present study, we investigated whether a CHI3L1-inhibiting natural compound, ebractenoid F, inhibits lung cancer cell growth and migration and induces apoptosis. Ebractenoid F concentration-dependently (0, 17, 35, 70 µM) and significantly inhibited the proliferation and migration of A549 and H460 lung cancer cells and induced apoptosis. In the mechanism study, we found that ebractenoid F bound to CHI3L1 and suppressed CHI3L1-associated AKT signaling. Combined treatment with an AKT inhibitor, LY294002, and ebractenoid F synergistically decreased the expression of CHI3L1. Moreover, the combination treatment further inhibited the growth and migration of lung cancer cells and further induced apoptosis, as well as the expression levels of apoptosis-related proteins. Thus, our data demonstrate that ebractenoid F may serve as a potential anti-lung cancer compound targeting CHI3L1-associated AKT signaling.

Chitinase 3-like 1 (Chi3L1) is associated with various biological processes, such as inflammation, tissue repair, proliferation, cell survival, invasion, and extracellular matrix remodeling. Recent studies indicated that Chi3L1 is critical for cancer development and metastasis. In this study, we demonstrate that Chi3L1 serum and tissue levels were significantly increased in lung cancer patients compared with controls. We previously developed an anti-Chi3L1-humanized antibody, and here, we investigate its antitumor and antimetastatic effect. The anti-Chi3L1 antibody attenuated tumor growth and metastasis both in vitro and in vivo in a lung cancer mouse model. These inhibitory effects are associated with signal transducer and activator of transcription 6 (STAT6)-dependent M2 polarization inhibition. Proteomics analysis revealed that plasminogen (PLG) interacts with Chi3L1 and affects M2 polarization. Chi3L1 plays a critical role in lung cancer progression, and the anti-Chi3L1 antibody could be a new anticancer therapy.

In oriental medicine, bee venom has long been used as a therapeutic agent against inflammatory diseases. Several studies have reported that isolated and purified bee venom components are effective in treating dementia, arthritis, inflammation, bacterial infections, and cancer. In previous studies, we reported that bee venom inhibits cell growth and induces apoptotic cell death in lung cancer cells. In the present study, we assessed whether bee venom affects autophagy and thereby induces apoptosis. Bee venom treatment increased the levels of autophagy-related proteins (Atg5, Beclin-1, and LC3-II) and the accumulation of LC3 puncta. We found that bee venom could induce autophagy by inhibiting the mTOR signaling pathway. In addition, we found that hydroxychloroquine (HCQ)- or si-ATG5-induced autophagy inhibition further demoted bee venom-induced apoptosis. Bee venom-induced autophagy promotes apoptosis in lung cancer cells and may become a new approach to cancer treatment.

Snake venom contains many proteins that help treat or prevent thrombosis, cardiovascular disease, and cancer, and many studies have been reported in this regard. It has recently been reported that autophagy exerts anticancer effects by inducing tumor cell death and inhibiting cell growth. In this study, we investigated the effect of snake venom on autophagy. Unlike normal colon cells, LC3-II protein levels and LC3 puncta accumulation are increased in snake venom-treated colorectal cancer cells. Inhibition of autophagy by treating cells with hydroxychloroquine, an autophagy inhibitor, prevented snake venom-induced cell death, indicating that snake venom indeed induces autophagic cell death in human colorectal cancer cells. In addition, we demonstrated that activated JNK, and not mTOR signaling, is an upstream effector controlling autophagy. Pretreatment with SP600125, a JNK inhibitor, reversed snake venom-induced autophagy and cell death, indicating that JNK plays a critical role in snake venom-induced autophagy. This study demonstrated that snake venom can function as an anticarcinogenby induction autophagy.

β-Catenin is a multifunctional protein and participates in numerous processes required for embryonic development, cell proliferation, and homeostasis through various molecular interactions and signaling pathways. To date, however, there is no direct evidence that β-catenin contributes to cytokinesis. Here, we identify a novel p-S60 epitope on β-catenin generated by Plk1 kinase activity, which can be found at the actomyosin contractile ring of early telophase cells and at the midbody of late telophase cells. Depletion of β-catenin leads to cytokinesis-defective phenotypes, which eventually result in apoptotic cell death. In addition, phosphorylation of β-catenin Ser60 by Plk1 is essential for the recruitment of Ect2 to the midbody, activation of RhoA, and interaction between β-catenin, Plk1, and Ect2. Time-lapse image analysis confirmed the importance of β-catenin phospho-Ser60 in furrow ingression and the completion of cytokinesis. Taken together, we propose that phosphorylation of β-catenin Ser60 by Plk1 in cooperation with Ect2 is essential for the completion of cytokinesis. These findings may provide fundamental knowledge for the research of cytokinesis failure-derived human diseases.

Our previous big data analyses showed a high level of association between chitinase 3 like1 (CHI3L1) expression and lung tumor development. In the present study, we investigated whether a CHI3L1‐inhibiting chemical, 2‐({3‐[2‐(1‐cyclohexen‐1‐yl)ethyl]‐6,7‐dimethoxy‐4‐oxo‐3,4‐dihydro‐2‐quinazolinyl}sulfanyl)‐N‐(4‐ethylphenyl)butanamide (K284), could inhibit lung metastasis and studied its mechanism of action. We investigated the antitumor effect of K284 both in vitro and in vivo. K284 (0.5 mg·kg−1 body weight) significantly inhibited lung metastasis in in vivo models after injection of murine melanoma cells (B16F10) or adenocarcinomic human alveolar basal epithelial cells (A549). K284 significantly and concentration‐dependently also inhibited cancer cell proliferation and migration in the A549 and H460 lung cancer cell lines. We found that the binding of K284 to the chitin‐binding domain (CBD) of CHI3L1 prevented the binding of CHI3L1 to its receptor, interleukin‐13 receptor subunit alpha‐2 (IL‐13Rα2), thereby suppressing the CHI3L1 signal. This blocking of the CHI3L1‐IL‐13Rα2 signal caused the inhibition of c‐Jun N‐terminal kinase (JNK)‐activator protein 1 (AP‐1) signals, resulting in the prevention of lung metastasis and cancer cell growth. Our data demonstrate that K284 may serve as a potential candidate anticancer compound targeting CHI3L1.

Extensive epidemiological evidence indicates that patients with certain cancers have a lower probability of developing some types of neurodegenerative diseases (ND) and mood disorders and vice versa. These inverse comorbidities may be associated with several different molecular processes. p53, is a potentially responsible for regulating the development of ND, mood disorders as well as cancers. To investigate whether the tumor suppressor p53 may be associated with ND development, we studied the behavioral changes in p53 knockout (p53−/−) mice and possible action mechanisms. Increased anxiety-like but not depression-like behaviors were displayed in p53−/− mice without impaired motor activities under the non-chronic unpredictable mild stress condition. However, in the p53−/− mice, more anxiety-like and depression-like behaviors were observed in the chronic unpredictable mild stress (CUMS) condition. Our mechanism studies showed that brain-derived neurotrophic factor (BDNF) protein was significantly downregulated, but glutamate levels were significantly increased in the prefrontal cortex of p53−/− mice. Further analyses showed that the p53−/− mice caused more stress-induced nerve damage as a result of an increase in intracellular calcium levels and N-methyl D-aspartate receptor subtype 2B (NMDAR2B) expression. Treatment with corticosterone (mimics CUMS in vitro) increased glutamate levels, NMDAR2B expression, and calcium levels, and these levels were elevated by co-treatment with pifithrin-α (p53 inhibitor) in PC12 cells. Cell death and cell death-mediated signals (p-p38, p-JNK and caspase-3) were upregulated, but neuroprotective signals (BDNF p-Akt, p-ERK and p-CREB) were downregulated in p53−/− mice, and corticoid and/or pifithrin-α treated PC12 cells. These data indicate that p53 may be an important preventive factor against depression and anxiety, and thus suggests a possible correlation between cancer and anxiety/depression development. Running title: Deficiency of p53 enhances mental disorder

Porcine reproductive and respiratory syndrome (PRRS) is recognized as one of the most important infectious diseases causing serious economic loss in the swine industry worldwide. Due to its increasing genetic diversity, a rapid and accurate diagnosis is critical for PRRS control. The immunochromatographic strip test (ICST) is a rapid and convenient type of immunoassay. In this study, an on-site immunochromatographic assay-based diagnostic method was developed for detection of PRRS virus (PRRSV)-specific antibodies. The method utilized colloidal gold nanoparticle-labeled dual-type nucleocapsid proteins encoded by open reading frame 7. We evaluated 991 field samples from pig farms and 66 serum samples from experimentally PRRSV-inoculated pigs. Based on true PRRSV-specific antibody-positive or -negative sera determined by immunofluorescence assay and IgM enzyme-linked immunosorbent assay (ELISA), the specificity and sensitivity of the ICST were 97.5% and 91.1%, respectively, similar to those of a commercial ELISA (IDEXX PRRS X3 Ab). More importantly, the ICST was completed within 15 min and could detect the PRRSV-specific antibody at an earlier stage of infection (3-7 days) than that of ELISA (7+ days). The results demonstrate that the developed ICST has great potential as an on-farm diagnostic method, providing excellent diagnostic performance in a quick and convenient manner.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes devastating disease characterized by reproductive failure and respiratory problems in the swine industry. To understand the recent prevalence and genetic diversity of field PRRSVs in the Republic of Korea, open reading frames (ORFs) 5 and 7 of PRRSV field isolates from 631 PRRS-affected swine farms nationwide in 2013–2016 were analyzed along with 200 Korean field viruses isolated in 2003–2010, and 113 foreign field and vaccine strains.

Influenza virus infection is a zoonosis that has great socioeconomic effects worldwide. Influenza infection induces respiratory symptoms, while the influenza virus can infect brain and leave central nervous system sequelae. As children are more vulnerable to infection, they are at risk of long-term neurological effects once their brains are infected. We previously demonstrated that functional changes in hippocampal neurons were observed in mice recovered from neonatal influenza infection. In this study, we investigated changes in myelination properties that could affect neural dysfunction. Mice were infected with the influenza virus on postnatal day 5. Tissues were harvested from recovered mice 21-days post-infection. The expression levels for myelin basic protein (MBP) were determined, and immunohistochemical staining and transmission electron microscopy were performed. Real-time polymerase chain reaction and Western blot analyses showed that mRNA and protein expressions increased in the hippocampus and cerebellum of recovered mice. Increased MBP-staining signal was observed in the recovered mouse brain. By calculating the relative thickness of myelin sheath in relation to nerve fiber diameter (G-ratio) from electron photomicrographs, an increased G-ratio was observed in both the hippocampus and cerebellum of recovered mice. Influenza infection in oligodendrocyte-enriched primary brain cell cultures showed that proinflammatory cytokines may induce MBP upregulation. These results suggested that increased MBP expression could be a compensatory change related to hypomyelination, which may underlie neural dysfunction in recovered mice. In summary, the present results demonstrate that influenza infection during the neonatal period affects myelination and further induces functional changes in influenza-recovered mouse brain.