Screening epitope peptides based on a phage-displayed random peptide and peptide microarrays to contribute to improving the diagnostic efficiency of systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is one of the most common autoimmune diseases in China. At present, there are hundreds of autoantibodies in SLE patients; however, only a dozen of the autoantibodies can be routinely detected, and the available diagnostic antibodies are not sufficient for diagnosis or differential diagnosis of SLE patients with atypical clinical manifestations or other autoimmune diseases. Therefore, it is necessary to find new diagnostic markers to improve the diagnostic effect of SLE.

METHODS

The displayed random peptide library and peptide microarray were combined to identify SLE-related epitope peptides. A case-control design was used. The IgG antibodies in the sera from SLE patients, healthy controls, and other autoimmune disease controls underwent a reaction with the phage-display random peptide library, respectively. Selected epitope peptides were used to construct a peptide chip. A total of 644 serum samples (including 296 SLE patients, 168 disease controls, and 180 healthy controls) were used for further screening and verification. Peptides with an area under the curve (AUC) > 0.650 were further verified by ELISA. Finally, 500 serum samples (including 200 SLE patients, 150 disease controls, and 150 healthy controls) were used to verify and evaluate the diagnostic and differential diagnostic efficacy of the selected peptides.

RESULTS

After the previous screening, five epitope peptides (SLE_P19, SLE_P20, SLE_P27, SLE_P28, and SLE_P29) may have potential as SLE diagnostic markers. Additionally, SLE_P27 was superior to the other four peptides in the diagnosis and differential diagnosis of SLE and rheumatoid arthritis (RA). The AUC of SLE_P27 was 0.938, the sensitivity was 76.00%, the specificity was 92.70%, the positive likelihood ratio was 10.411, the negative likelihood ratio was 0.259, and the accuracy was 84.40%. The diagnostic efficacy of SLE can be increased by combining the five selected peptides with the anti-double stranded DNA antibody (anti-dsDNA)and anti-Smith antibodies (anti-Sm).

CONCLUSIONS

In this study, we identified five peptides that may serve as potential biomarkers for SLE diagnosis using the strategy of combining the displayed random peptide library with the peptide microarray. The combination of selected peptides and existing autoantibodies can significantly improve the diagnostic efficiency. These specific peptides are expected to be new diagnostic markers for SLE.

CD74 regulates cellularity and maturation of medullary thymic epithelial cells partially by activating the canonical NF-κB signaling pathway

Thymic epithelial cells (TECs) are indispensable for T cell development, T cell receptor (TCR) repertoire selection, and specific lineage differentiation. Medullary thymic epithelial cells (mTECs), which account for the majority of TECs in adults, are critical for thymocyte selection and self-tolerance. CD74 is a nonpolymorphic transmembrane glycoprotein of major histocompatibility complex class II (MHCII) that is expressed in TECs. However, the exact role of CD74 in regulating the development of mTEC is poorly defined. In this research, we found that loss of CD74 resulted in a significant diminution in the medulla, a selective reduction in the cell number of mature mTECs expressing CD80 molecules, which eventually led to impaired thymic CD4⁺ T cell development. Moreover, RNA-sequence analysis showed that CD74 deficiency obviously downregulated the canonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway in mTECs. Our results suggest that CD74 positively controls mTEC cellularity and maturation partially by activating the canonical NF-κB signaling pathway.

The inhibition of the breast cancer by PPARγ agonist pioglitazone through JAK2/STAT3 pathway

Breast cancer, especially triple-negative breast cancer, is one of the deadliest cancers in women. To date, there is a lack of a good therapeutic regimen for it. PPARγ has been reported to be a tumor suppressor and could be activated by many agonists involved in cancer inhibition. Therefore, the expression of PPARγ in breast cancer was analyzed by online software UALCAN whose data were from the TCGA database. The results revealed that the PPARγ expression was reduced in breast cancer tissues. Furthermore, the methylation in the PPARγ promoter was also assayed and the results indicated that the methylation level in the PPARγ promoter in breast cancer tissue was higher than that in normal tissue. In order to verify the methylation in promoter involved in the regulation of gene PPARγ expression, the 5'-Aza and fluorescence assays were performed and the results proved that methylation in promoter participated in gene PPARγ expression regulation. Pioglitazone, a PPARγ agonist, still was not investigated in breast cancer. Therefore, the effects of pioglitazone on breast cancer cells were tested by cell viability, scratch and transwell assays, and results indicated that the pioglitazone has the inhibition effect on the proliferation and migration of breast cancer cells by PPARγ which was correlated with the JAK2/STAT3 pathway. In order to further confirm the inhibition effect of pioglitazone on breast cancer in vivo, the nude mice model was administrated by gavage with pioglitazone. And the results indicated that pioglitazone could inhibit the growth of breast cancer in the PPARγ overexpression group in vivo. In summary, the expression of gene PPARγ was decreased in breast cancer tissues, which was correlated with its methylation in the promoter region. Moreover, pioglitazone could exert its inhibition on breast cancer proliferation and migration by the JAK2/STAT3 pathway.

Thymic Epithelial Cells Contribute to Thymopoiesis and T Cell Development

The thymus is the primary lymphoid organ responsible for the generation and maturation of T cells. Thymic epithelial cells (TECs) account for the majority of thymic stromal components. They are further divided into cortical and medullary TECs based on their localization within the thymus and are involved in positive and negative selection, respectively. Establishment of self-tolerance in the thymus depends on promiscuous gene expression (pGE) of tissue-restricted antigens (TRAs) by TECs. Such pGE is co-controlled by the autoimmune regulator (Aire) and forebrain embryonic zinc fingerlike protein 2 (Fezf2). Over the past two decades, research has found that TECs contribute greatly to thymopoiesis and T cell development. In turn, signals from T cells regulate the differentiation and maturation of TECs. Several signaling pathways essential for the development and maturation of TECs have been discovered. New technology and animal models have provided important observations on TEC differentiation, development, and thymopoiesis. In this review, we will discuss recent advances in classification, development, and maintenance of TECs and mechanisms that control TEC functions during thymic involution and central tolerance.

The anti-parasitic drug suramin potently inhibits formation of seminal amyloid fibrils and their interaction with HIV-1

Seminal amyloid fibrils are made up of naturally occurring peptide fragments and are key targets for the development of combination microbicides or antiviral drugs. Previously, we reported that the polysulfonic compound ADS-J1 is a potential candidate microbicide that not only inhibits HIV-1 entry, but also seminal fibrils. However, the carcinogenic azo moieties in ADS-J1 preclude its clinical application. Here, we screened several ADS-J1-like analogs and found that the antiparasitic drug suramin most potently inhibited seminal amyloid fibrils. Using various biochemical methods, including Congo red staining, CD analysis, transmission EM, viral infection assays, surface plasmon resonance imaging, and molecular dynamics simulations, we investigated suramin's inhibitory effects and its putative mechanism of action. We found that by forming a multivalent interaction, suramin binds to proteolytic peptides and mature fibrils, thereby inhibiting seminal fibril formation and blocking fibril-mediated enhancement of viral infection. Of note, suramin exhibited potent anti-HIV activities, and combining suramin with several antiretroviral drugs produced synergistic effects against HIV-1 in semen. Suramin also displayed a good safety profile for vaginal application. Moreover, suramin inhibited the semen-derived enhancer of viral infection (SEVI)/semen-mediated enhancement of HIV-1 transcytosis through genital epithelial cells and the subsequent infection of target cells. Collectively, suramin has great potential for further development as a combination microbicide to reduce the spread of the AIDS pandemic by targeting both viral and host factors involved in HIV-1 sexual transmission.

Long noncoding RNA NEXN-AS1 mitigates atherosclerosis by regulating the actin-binding protein NEXN

Noncoding RNAs are emerging as important players in gene regulation and disease pathogeneses. Here, we show that a previously uncharacterized long noncoding RNA, nexilin F-actin binding protein antisense RNA 1 (NEXN-AS1), modulates the expression of the actin-binding protein NEXN and that NEXN exerts a protective role against atherosclerosis. An expression microarray analysis showed that the expression of both NEXN-AS1 and NEXN was reduced in human atherosclerotic plaques. In vitro experiments revealed that NEXN-AS1 interacted with the chromatin remodeler BAZ1A and the 5' flanking region of the NEXN gene and that it also upregulated NEXN expression. Augmentation of NEXN-AS1 expression inhibited TLR4 oligomerization and NF-κB activity, downregulated the expression of adhesion molecules and inflammatory cytokines by endothelial cells, and suppressed monocyte adhesion to endothelial cells. These inhibitory effects of NEXN-AS1 were abolished by knockdown of NEXN. In vivo experiments using ApoE-knockout mice fed a Western high-fat diet demonstrated that NEXN deficiency promoted atherosclerosis and increased macrophage abundance in atherosclerotic lesions, with heightened expression of adhesion molecules and inflammatory cytokines, whereas augmented NEXN expression deterred atherosclerosis. Patients with coronary artery disease were found to have lower blood NEXN levels than healthy individuals. These results indicate that NEXN-AS1 and NEXN represent potential therapeutic targets in atherosclerosis-related diseases.

Dysregulated ICOS+ proinflammatory and suppressive regulatory T cells in patients with rheumatoid arthritis

Regulatory T cells (Tregs) serve an important role in the pathogenesis of rheumatoid arthritis (RA) by regulating autoimmunity and inflammation. Humans and mice contain inducible T-cell costimulator-positive (ICOS⁺) Tregs, although their role in RA is unclear. A total of 33 patients with RA and 17 normal control (NC) subjects were examined. The proportion of ICOS⁺ Tregs in the peripheral blood and intracellular cytokine levels in these cells were assessed using flow cytometry. The percentage of ICOS⁺ Tregs increased in the cohort of patients with RA compared with the NCs. Such increases were much larger in patients with inactive RA compared with patients with active RA. Additionally, ICOS⁺ Tregs expressed multiple suppressive cytokines, including interleukin (IL)-10, transforming growth factor-β and IL-35, but expressed low levels of IL-17. Importantly, the expression of suppressive cytokines in ICOS⁺ Tregs from patients with active RA decreased, but IL-17 expression noticeably increased compared with patients with inactive RA. The present findings suggested that ICOS⁺ Tregs may perform inflammatory and inhibitory functions, and abnormal ICOS⁺ Tregs numbers and functions may contribute to the pathogenesis of RA.

NLRP3 in human glioma is correlated with increased WHO grade, and regulates cellular proliferation, apoptosis and metastasis via epithelial-mesenchymal transition and the PTEN/AKT signaling pathway

Glioma is the most prevalent and fatal primary tumor of the central nervous system in adults, while the development of effective therapeutic strategies in clinical practice remain a challenge. Nucleotide-binding domain leucine-rich family pyrin-containing 3 (NLRP3) has been reported to be associated with tumorigenesis and progression; however, its expression and function in human glioma remain unclear. The present study was designed to explore the biological role and potential mechanism of NLRP3 in human glioma. The results demonstrated that overexpression of NLRP3, apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC), caspase-1 and interleukin (IL)-1β protein in human glioma tissues were significantly correlated with higher World Health Organization grades. The in vitro biological experiments demonstrated that NLRP3 downregulation significantly inhibited the proliferation, migration and invasion, and promoted the apoptosis of SHG44 and A172 glioma cell lines. Furthermore, western blot assays revealed that the downregulation of NLRP3 significantly reduced the expression of ASC, caspase-1 and IL-1β protein. Furthermore, NLRP3 knockdown caused the inhibition of epithelial-mesenchymal transition (EMT), and inhibited the phosphorylation of AKT serine/threonine kinase (AKT) and phosphorylation of phosphatase and tensin homolog (PTEN). Consistently, the upregulation of NLRP3 significantly increased the expression of ASC, caspase-1, IL-1β and phosphorylated-PTEN, promoted proliferation, migration, invasion and EMT, inhibited apoptosis, and activated the AKT signaling pathway. The data of the present study indicate that NLRP3 affects human glioma progression and metastasis through multiple pathways, including EMT and PTEN/AKT signaling pathway regulation, enhanced inflammasome activation, and undefined inflammasome-independent mechanisms. Understanding the biological effects of NLRP3 in human glioma and the underlying mechanisms may offer novel insights for the development of glioma clinical therapeutic strategies.

Ginsenoside Rh2 inhibits human A172 glioma cell proliferation and induces cell cycle arrest status via modulating Akt signaling pathway

Ginsenoside Rh2 (G-Rh2), the main bioactive component in American ginseng, is known to exert a wide variety of biological activities. Accumulating evidence suggests that G-Rh2 inhibits cell proliferation and induces apoptosis of tumor cells. However, the possible mechanism through which G-Rh2 exerts its action on malignant glioma cells have not been completely elucidated. The findings of the present study demonstrated that G-Rh2 decreased the viability of glioma cells in a dose- and time-dependent manner, and induced cell cycle arrest. G-Rh2-induced cell cycle arrest was accompanied by the downregulation of cyclin-dependent kinase 4 and Cyclin E. In addition, G-Rh2 markedly reduced the expression of total- RAC-α serine/threonine-protein kinase (Akt) and the levels of phosphorylated-Akt. These findings provide mechanistic details of how G-Rh2 acts on glioma cells and suggest that G-Rh2 may function as a potential anti-cancer drug for glioma treatment.

Expression of IncRNA UCA1 in ovarian cancer and its clinical significance

OBJECTIVES

To explore the expression and clinical significance of IncRNA-UCA1 in ovarian cancer.

MATERIALS AND METHODS

The ex- pression of IncRNA-UCA1 in 26 ovarian cancer tissue and 16 normal and benign ovarian tissue were detected using qRT-PCR method, and the correlation of expression level with clinicopathological features were analyzed.

RESULTS

Higher lncRNA-UCA1 expression level were detected in ovarian cancer tissue than those in normal ovarian tissue (p < 0.05). There were significant correlations between higher expression of IncRNA-UCA1 with tumor staging (p = 0.000), histological grades (p = 0.000), peritoneal effusion (p = 0.001), and lymph node metastasis (p = 0.000), but not with age.

CONCLUSION

IncRNA-UCA1 may play a vital role in the metastasis of ovarian cancer and it is expected to be a potential novel biomarker and therapeutic target of ovarian cancer.

Long non-coding RNA RP5-833A20.1 inhibits proliferation, metastasis and cell cycle progression by suppressing the expression of NFIA in U251 cells

Early reports suggest that nuclear factor IA (NFIA) is important in the pathogenesis of glioma. Our previous study demonstrated that the long non‑coding RNA (lncRNA), RP5‑833A20.1, suppressed the expression of NFIA in THP‑1 macrophage-derived foam cells. However, the effect and possible mechanism of RP5‑833A20.1 on glioma remains to be fully elucidated, and whether the NFIA-dependent pathway is involved in its progression has not been investigated. In the present study, the mechanisms by which RP5‑833A20.1 regulates the expression of NFIA in glioma were investigated. The expression levels of RP5‑833A20.1 and NFIA were determined in U251 cells and clinical samples using reverse transcription‑quantitative polymerase chain reaction (PCR) analysis. The effects of RP5‑833A20.1 on cell proliferation, invasion, cell cycle and apoptosis were evaluated using in vitro assays. The potential changes in protein expression were investigated using western blot analysis. The methylation status of the CpG island in the NFIA promoter was determined using bisulfite PCR (BSP) sequencing. It was found that the expression of RP5‑833A20.1 was downregulated, whereas the expression of NFIA was upregulated in glioma tissues, compared with corresponding adjacent nontumor tissues from 20 patients with glioma. The overexpression of RP5‑833A20.1 inhibited proliferation and cell cycle progression, and induced apoptosis in the U251 cells. The mRNA and protein levels of NFIA were markedly inhibited by overexpression of RP5‑833A20.1 in the U251 cells. The overexpression of RP5‑833A20.1 increased the expression of microRNA‑382‑5p in the U251 cells. The BSP assay revealed that the overexpression of RP5‑833A20.1 enhanced the methylation level of the NFIA promoter. These results demonstrated that RP5‑833A20.1 inhibited tumor cell proliferation, induced apoptosis and inhibited cell‑cycle progression by suppressing the expression of NFIA in U251 cells. Collectively, these results indicated RP5‑833A20.1 as a novel therapeutic target for glioma.

mTOR is critical for intestinal T-cell homeostasis and resistance to Citrobacter rodentium

T-cells play an important role in promoting mucosal immunity against pathogens, but the mechanistic basis for their homeostasis in the intestine is still poorly understood. We report here that T-cell-specific deletion of mTOR results in dramatically decreased CD4 and CD8 T-cell numbers in the lamina propria of both small and large intestines under both steady-state and inflammatory conditions. These defects result in defective host resistance against a murine enteropathogen, Citrobacter rodentium, leading to the death of the animals. We further demonstrated that mTOR deficiency reduces the generation of gut-homing effector T-cells in both mesenteric lymph nodes and Peyer’s patches without obviously affecting expression of gut-homing molecules on those effector T-cells. Using mice with T-cell-specific ablation of Raptor/mTORC1 or Rictor/mTORC2, we revealed that both mTORC1 and, to a lesser extent, mTORC2 contribute to both CD4 and CD8 T-cell accumulation in the gastrointestinal (GI) tract. Additionally, mTORC1 but not mTORC2 plays an important role regulating the proliferative renewal of both CD4 and CD8 T-cells in the intestines. Our data thus reveal that mTOR is crucial for T-cell accumulation in the GI tract and for establishing local adaptive immunity against pathogens.

Ox-LDL Upregulates IL-6 Expression by Enhancing NF-κB in an IGF2-Dependent Manner in THP-1 Macrophages

Interleukin 6 (IL-6) is a pro-inflammatory cytokine that is well established as a vital factor in determining the risk of coronary heart disease and pathogenesis of atherosclerosis. Moreover, accumulating evidences have shown that oxidized low-density lipoprotein (ox-LDL) can promote IL-6 expression in macrophages. Nevertheless, the underlying mechanism of how ox-LDL upregulates IL-6 expression remains largely unexplained. We found that the expression of insulin-like growth factor 2 (IGF2), nuclear factor kappa B (NF-κB), and IL-6 was upregulated at both the messenger RNA (mRNA) and protein levels in a dose-dependent manner when treated with 0, 25, 50, or 100 μg/mL of ox-LDL for 48 h in THP-1 macrophages. Moreover, overexpression of IGF2 significantly upregulated NF-κB and IL-6 expressions in THP-1 macrophages. However, the upregulation of NF-κB and IL-6 expressions induced by ox-LDL were significantly abolished by IGF2 small interfering RNA (siRNA) in THP-1 macrophages. Further studies indicated the upregulation of IL-6 induced by ox-LDL could be abolished when treated with NF-κB siRNA in THP-1 macrophages. Ox-LDL might upregulate IL-6 in the cell and its secretion via enhancing NF-κB in an IGF2-dependent manner in THP-1 macrophages.

The miR-573/apoM/Bcl2A1-dependent signal transduction pathway is essential for hepatocyte apoptosis and hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with an increasing incidence worldwide. Apolipoprotein M (apoM) is a novel apolipoprotein that is mainly expressed in liver and kidney tissues. However, the anti-tumor properties of apoM remain largely unknown. We evaluated the anti-tumor activities and mechanisms of apoM in HCC both in vivo and in vitro. Bioinformatic analysis and luciferase reporter assay results showed that apoM was a potential target of hsa-miR-573 and was downregulated after transfection with hsa-miR-573 mimics. Overexpression of apoM suppressed migration, invasion, and proliferation of hepatoma cells in vitro. Overexpression of hsa-miR-573 in hepatoma cells reduced apoM expression, leading to promotion of the invasion, migration, and proliferation of hepatoma cells in vitro. In addition, hsa-miR-573 markedly promoted growth of xenograft tumors in nude mice with an accompanying reduction in cell apoptosis. ApoM markedly inhibited growth of xenograft tumors in nude mice and promoted cell apoptosis. Moreover, Bcl2A1 mRNA and protein levels were inhibited by apoM overexpression and an increase in apoptosis rate by apoM was markedly compensated by Bcl2A1 overexpression in HepG2 cells. These results provide evidence that hsa-miR-573 promoted tumor growth by inhibition of hepatocyte apoptosis and this pro-tumor effect might be mediated through Bcl2A1 in an apoM-dependent manner. Therefore, our findings may be useful to improve understanding of the critical effects of hsa-miR-573 and apoM in HCC pathogenesis.

VNN1 promotes atherosclerosis progression in apoE-/- mice fed a high-fat/high-cholesterol diet

Accumulated evidence shows that vanin-1 (VNN1) plays a key part in glucose metabolism. We explored the effect of VNN1 on cholesterol metabolism, inflammation, apoptosis in vitro, and progression of atherosclerotic plaques in apoE^−/− mice. Oxidized LDL (Ox-LDL) significantly induced VNN1 expression through an ERK1/2/cyclooxygenase-2/PPARα signaling pathway. VNN1 significantly increased cellular cholesterol content and decreased apoAI and HDL-cholesterol (HDL-C)-mediated efflux by 25.16% and 23.13%, respectively, in THP-1 macrophage-derived foam cells (P < 0.05). In addition, VNN1 attenuated Ox-LDL-induced apoptosis through upregulation of expression of p53 by 59.15% and downregulation of expression of B-cell lymphoma-2 127.13% in THP-1 macrophage (P < 0.05). In vivo, apoE^−/− mice were divided randomly into two groups and transduced with lentivirus (LV)-Mock or LV-VNN1 for 12 weeks. VNN1-treated mice showed increased liver lipid content and plasma levels of TG (124.48%), LDL-cholesterol (119.64%), TNF-α (148.74%), interleukin (IL)-1β (131.81%), and IL-6 (156.51%), whereas plasma levels of HDL-C (25.75%) were decreased significantly (P < 0.05). Consistent with these data, development of atherosclerotic lesions was increased significantly upon infection of apoE^−/− mice with LV-VNN1. These observations suggest that VNN1 may be a promising therapeutic candidate against atherosclerosis.

Dihydrocapsaicin suppresses proinflammatory cytokines expression by enhancing nuclear factor IA in a NF-κB-dependent manner

BACKGROUND

Atherosclerosis is a chronic inflammatory disease and represents the leading cause of morbidity and mortality throughout the world. Accumulating evidences have showed that Dihydrocapsaicin (DHC) has been found to exert multiple pharmacological and physiological effects. Nevertheless, the effects and possible mechanism of DHC on proinflammatory response remain largely unexplained.

METHODS AND RESULTS

We found that DHC markedly upregulated NFIA and suppressed NF-κB expression in THP-1 macrophages. Up-regulation of proinflammatory cytokines induced by LPS including TNF-α, IL-1β and IL-6 were markedly suppressed by DHC treatment. We also observed that protein level of NFIA was significantly increased while NF-κB and proinflammatory cytokines were decreased by DHC treatment in apoE(-/-) mice. Lentivirus-mediated overexpression of NFIA suppressed NF-κB and proinflammatory cytokines expression both in THP-1 macrophages and plaque tissues of apoE-/- mice. Moreover, treatment with lentivirus-mediated overexpression of NFIA made the down-regulation of DHC on NF-κB and proinflammatory cytokines expression notably accentuated in THP-1 macrophages and apoE(-/-) mice. In addition, treatment with siRNA targeting NF-κB accentuated the suppression of proinflammatory cytokines by lentivirus-mediated overexpression of NFIA.

CONCLUSION

These observations demonstrated that DHC can significantly decrease proinflammatory cytokines through enhancing NFIA and inhibiting NF-κB expression and thus DHC may be a promising candidate as an anti-inflammatory drug for atherosclerosis as well as other disorders.

mTORC2 in Thymic Epithelial Cells Controls Thymopoiesis and T Cell Development

Thymic epithelial cells (TECs) play important roles in T cell generation. Mechanisms that control TEC development and function are still not well defined. The mammalian or mechanistic target of rapamycin complex (mTORC)2 signals to regulate cell survival, nutrient uptake, and metabolism. We report in the present study that mice with TEC-specific ablation of Rictor, a critical and unique adaptor molecule in mTORC2, display thymic atrophy, which accompanies decreased TEC numbers in the medulla. Moreover, generation of multiple T cell lineages, including conventional TCRαβ T cells, regulatory T cells, invariant NKT cells, and TCRγδ T cells, was reduced in TEC-specific Rictor-deficient mice. Our data demonstrate that mTORC2 in TECs is important for normal thymopoiesis and efficient T cell generation.

mTORC1 in Thymic Epithelial Cells Is Critical for Thymopoiesis, T-Cell Generation, and Temporal Control of γδT17 Development and TCRγ/δ Recombination

Thymus is crucial for generation of a diverse repertoire of T cells essential for adaptive immunity. Although thymic epithelial cells (TECs) are crucial for thymopoiesis and T cell generation, how TEC development and function are controlled is poorly understood. We report here that mTOR complex 1 (mTORC1) in TECs plays critical roles in thymopoiesis and thymus function. Acute deletion of mTORC1 in adult mice caused severe thymic involution. TEC-specific deficiency of mTORC1 (mTORC1KO) impaired TEC maturation and function such as decreased expression of thymotropic chemokines, decreased medullary TEC to cortical TEC ratios, and altered thymic architecture, leading to severe thymic atrophy, reduced recruitment of early thymic progenitors, and impaired development of virtually all T-cell lineages. Strikingly, temporal control of IL-17-producing γδT (γδT17) cell differentiation and TCRVγ/δ recombination in fetal thymus is lost in mTORC1KO thymus, leading to elevated γδT17 differentiation and rearranging of fetal specific TCRVγ/δ in adulthood. Thus, mTORC1 is central for TEC development/function and establishment of thymic environment for proper T cell development, and modulating mTORC1 activity can be a strategy for preventing thymic involution/atrophy.

The thymus is essential for making T cells but undergoes age- or stress-associated atrophy. This study demonstrates that mTOR complex 1 in thymic epithelial cells is crucial for correct thymic architecture and the production of mature T cells.

The thymus is the primary organ for T cell generation. Abnormal thymus function profoundly affects host immunity and numerous diseases. Thymopoiesis and thymus function rely on orchestrated interaction between multiple cell types representing different origins. Among them, thymic epithelial cells (TECs) are crucial for thymus development and maintenance and T cell generation. How TEC development and function are regulated is poorly understood. The mammalian/mechanistic target of rapamycin (mTOR), a serine/threonine kinase, signals with two complexes, mTORC1 and mTOC2, to control metabolism, growth, proliferation, and survival. Using a mouse model with mTORC1 selectively ablated in TECs, we demonstrate that mTORC1 in TECs plays critical roles in thymopoiesis and thymus function. Absence of mTORC1 results in impaired TEC maturation and function, altered thymic architecture, severe thymic atrophy, and impaired development of virtually all T-cell lineages. Moreover, it also causes increased generation of IL-17–producing γδT (γδT17) cells and fetal-specific γδT subsets in adult thymus, revealing that mTORC1 in TECs is central for temporal control of γδT17 differentiation and TCRVγ/δ recombination. Our results establish mTORC1 as a central regulator for TEC development/function and for the establishment of normal thymic environment for proper T cell development. We suggest modulating mTORC1 activity as a strategy for preventing thymic involution/atrophy.

Lipoxin A4 promotes ABCA1 expression and cholesterol efflux through the LXRα signaling pathway in THP-1 macrophage-derived foam cells

Adenosine triphosphate-binding cassette transporter A1 (ABCA1) is a crucial cholesterol transporter and plays a central role in the high density lipoproteins (HDL) cholesterol metabolism and lipid clearance from the foam cell. Lipoxin A4 (LXA4) is an endogenous lipid mediator that requires cell-cell interaction or cell-platelet interaction for its synthesis. The roles of LXA4 on inflammatory responses are well described, while its effects on mediating ABCA1 and underlying mechanisms remain unclear. In this study, we showed that LXA4 significantly increases expression of ABCA1 and LXRα in a dose-dependent manner in THP-1 macrophage-derived foam cells. Cellular cholesterol content was decreased while cholesterol efflux was increased by LXA4 treatment. However, after short interfering RNA of LXRα, the effects of LXA4 on ABCA1 expression and cholesterol metabolism were significantly abolished. These results provide evidence that LXA4 increases ABCA1 expression and promotes cholesterol efflux through LXRα pathway in THP-1 macrophage-derived foam cells.

RP5-833A20.1/miR-382-5p/NFIA-dependent signal transduction pathway contributes to the regulation of cholesterol homeostasis and inflammatory reaction

OBJECTIVE

Cardiovascular disease caused by atherosclerosis is the number one cause of death in Western countries and threatens to become the major cause of morbidity and mortality worldwide. Long noncoding RNAs are emerging as new players in gene regulation, but how long noncoding RNAs operate in the development of atherosclerosis remains unclear.

APPROACH AND RESULTS

Using microarray analysis, we found that long noncoding RNA RP5-833A20.1 expression was upregulated, whereas nuclear factor IA (NFIA) expression was downregulated in human acute monocytic leukemia macrophage-derived foam cells. Moreover, we showed that long noncoding RNA RP5-833A20.1 may decreases NFIA expression by inducing hsa-miR-382-5p expression in vitro. We found that the RP5-833A20.1/hsa-miR-382-5p/NFIA pathway is essential to the regulation of cholesterol homeostasis and inflammatory responses in human acute monocytic leukemia macrophages. Lentivirus-mediated NFIA overexpression increased high-density lipoprotein cholesterol circulation, reduced low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol circulation, decreased circulation of inflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-α, and C-reactive protein, enhanced reverse cholesterol transport, and promoted regression of atherosclerosis in apolipoprotein E-deficient mice.

CONCLUSIONS

Our findings indicated that the RP5-833A20.1/miR-382-5p/NFIA pathway was essential to the regulation of cholesterol homeostasis and inflammatory reactions and suggested that NFIA may represent a therapeutic target to ameliorate cardiovascular disease.

An agomir of miR-144-3p accelerates plaque formation through impairing reverse cholesterol transport and promoting pro-inflammatory cytokine production

Aims

ATP-binding cassette transporter A1 (ABCA1) mediates the efflux of cholesterol and phospholipids to lipid-poor apolipoproteins, which then form nascent HDL, a key step in the mechanism of reverse cholesterol transport (RCT). While a series of microRNAs (miRNAs) have been identified as potent post-transcriptional regulators of lipid metabolism, their effects on ABCA1 function and associated mechanisms remain unclear.

Methods and Results

ABCA1 was identified as a potential target of miR-144-3p, based on the results of bioinformatic analysis and the luciferase reporter assay, and downregulated after transfection of cells with miR-144-3p mimics, as observed with real-time PCR and western blot. Moreover, miR-144-3p mimics (agomir) enhanced the expression of inflammatory factors, including IL-1β, IL-6 and TNF-α, in vivo and in vitro, inhibited cholesterol efflux in THP-1 macrophage-derived foam cells, decreased HDL-C circulation and impaired RCT in vivo, resulting in accelerated pathological progression of atherosclerosis in apoE^−/− mice. Clinical studies additionally revealed a positive correlation of circulating miR-144-3p with serum CK, CK-MB, LDH and AST in subjects with AMI.

Conclusions

Our findings clearly indicate that miR-144-3p is essential for the regulation of cholesterol homeostasis and inflammatory reactions, supporting its utility as a potential therapeutic target of atherosclerosis and a promising diagnostic biomarker of AMI.

A lincRNA-DYNLRB2-2/GPR119/GLP-1R/ABCA1-dependent signal transduction pathway is essential for the regulation of cholesterol homeostasis

Accumulated evidence shows that G protein-coupled receptor 119 (GPR119) plays a key role in glucose and lipid metabolism. Here, we explored the effect of GPR119 on cholesterol metabolism and inflammation in THP-1 macrophages and atherosclerotic plaque progression in apoE(-/-) mice. We found that oxidized LDL (Ox-LDL) significantly induced long intervening noncoding RNA (lincRNA)-DYNLRB2-2 expression, resulting in the upregulation of GPR119 and ABCA1 expression through the glucagon-like peptide 1 receptor signaling pathway. GPR119 significantly decreased cellular cholesterol content and increased apoA-I-mediated cholesterol efflux in THP-1 macrophage-derived foam cells. In vivo, apoE(-/-) mice were randomly divided into two groups and infected with lentivirus (LV)-Mock or LV-GPR119 for 8 weeks. GPR119-treated mice showed decreased liver lipid content and plasma TG, interleukin (IL)-1β, IL-6, and TNF-α levels, whereas plasma levels of apoA-I were significantly increased. Consistent with this, atherosclerotic lesion development was significantly inhibited by infection of apoE(-/-) mice with LV-GPR119. Our findings clearly indicate that, Ox-LDL significantly induced lincRNA-DYNLRB2-2 expression, which promoted ABCA1-mediated cholesterol efflux and inhibited inflammation through GPR119 in THP-1 macrophage-derived foam cells. Moreover, GPR119 decreased lipid and serum inflammatory cytokine levels, decreasing atherosclerosis in apoE(-/-) mice. These suggest that GPR119 may be a promising candidate as a therapeutic agent.

Dihydrocapsaicin Attenuates Plaque Formation through a PPARγ/LXRα Pathway in apoE(-/-) Mice Fed a High-Fat/High-Cholesterol Diet

Aims

Atherosclerosis is a chronic inflammatory disease and represents the major cause of cardiovascular morbidity and mortality. There is evidence that dihydrocapsaicin (DHC) can exert multiple pharmacological and physiological effects. Here, we explored the effect of DHC in atherosclerotic plaque progression in apoE^−/− mice fed a high-fat/high-cholesterol diet.

Methods and Results

apoE^−/− mice were randomly divided into two groups and fed a high-fat/high-cholesterol diet with or without DHC for 12 weeks. We demonstrated that cellular cholesterol content was significantly decreased while apoA1-mediated cholesterol efflux was significantly increased following treatment with DHC in THP-1 macrophage-derived foam cells. We also observed that plasma levels of TG, LDL-C, VLDL-C, IL-1β, IL-6, TNF-α and CRP were markedly decreased while plasma levels of apoA1 and HDL-C were significantly increased, and consistent with this, atherosclerotic lesion development was significantly inhibited by DHC treatment of apoE^−/− mice fed a high-fat/high-cholesterol diet. Moreover, treatment with both LXRα siRNA and PPARγ siRNA made the up-regulation of DHC on ABCA1, ABCG1, ABCG5, SR-B1, NPC1, CD36, LDLR, HMGCR, apoA1 and apoE expression notably abolished while made the down-regulation of DHC on SRA1 expression markedly compensated. And treatment with PPARγ siRNA made the DHC-induced up-regulation of LXRα expression notably abolished while treatment with LXRα siRNA had no effect on DHC-induced PPARγ expression.

Conclusion

These observations provide direct evidence that DHC can significantly decrease atherosclerotic plaque formation involving in a PPARγ/LXRα pathway and thus DHC may represent a promising candidate for a therapeutic agent for the treatment or prevention of atherosclerosis.

A primer design strategy for PCR amplification of GC-rich DNA sequences

OBJECTIVES

To establish a primer design method for amplification of GC-rich DNA sequences.

DESIGN AND METHODS

A group of 15 pairs of primers with higher T(m) (>79.7°C) and lower level ΔT(m) (<1°C) were designed to amplify GC-rich sequences (66.0%-84.0%). The statistical analysis of primer parameters and GC content of PCR products was performed and compared with literatures. Other control experiments were conducted using shortened primers for GC-rich PCR amplifications in this study, and the statistical analysis of shortened primer parameters and GC content of PCR products was performed compared with primers not shortened. A group of 26 pairs of primers were designed to test the applicability of this primer designing strategy in amplifications of non-GC-rich sequences (35.2%-53.5%).

RESULTS

All the DNA sequences in this study were successfully amplified. Statistical analyses show that the T(m) and ΔT(m) were the main factors influencing amplifications.

CONCLUSIONS

This primer designing strategy offered a perfect tool for amplification of GC-rich sequences. It proves that the secondary structures cannot be formed at higher annealing temperature conditions (>65°C), and we can overcome this difficulty easily by designing primers and using higher annealing temperature.

A PTPN22 promoter polymorphism -1123G>C is associated with RA pathogenesis in Chinese

The minor allele of the non-synonymous single nucleotide polymorphism (SNP) +1858C>T within the PTPN22 gene has now been unequivocally confirmed as conferring susceptibility to RA in population from Europe and America, but not in population from Asia. The aim of this study was to jointly address and integrate these separate findings to further elucidate the association between the PTPN22 gene and RA in Chinese Hans of Guangdong province. Four hundred and ninety-four cases with RA and 496 healthy controls were randomly selected, their SNPs at position -1123G>C (rs2488457), +1858C>T (rs2476601), +788G>A (rs33996649), and rs1310182 were genotyped using PCR-RFLP, followed by agarose gel electrophoresis. +1858C>T (rs2476601) and +788G>A (rs33996649) are not polymorphic in Chinese Hans. Meanwhile, our result reveals that the degree of association between the promoter polymorphism, -1123G>C and RA, was analogous to that observed in Japanese reports (odds ratio [OR] = 1.517, 95% CI = [1.154-1.995], P = 0.003). Expression study also indicated a tendency for association between -1123G>C and PTPN22 gene expression. Our study underpins that the promoter polymorphism, -1123G/C, may be a causal SNP for RA in Asian.

[Diagnostic value of serum procalcitonin and C-reaction protein in acute exacerbation of chronic bronchitis]

OBJECTIVE

To evaluate the diagnostic value of serum procalcitonin (PCT) and C-reactive protein (CRP) in patients with acute exacerbation of chronic bronchitis.

METHODS

The PCT and CRP levels were detected in 56 patients with acute exacerbation of chronic bronchitis and 58 healthy control subjects.

RESULTS

The serum PCT level and positivity rate were significantly higher in the case group than in the control group (P<0.05); the serum CRP level was also significantly higher in the case group (P<0.05), but the positivity rate of CRP was similar between the two groups (P>0.05). The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy rate of PCT were higher than those of CRP.

CONCLUSION

Serum PCT is more sensitive than CRP in the diagnoses of acute exacerbation of chronic bronchitis, and can be used as a specific indicator for monitoring the condition of the patients.

[Relationship between surface molecules and RelB gene expression in DC2.4 cell line]

OBJECTIVE

To explore the relationship between the expression of the nuclear factor-kappaB transcription factor RelB gene and the surface molecules in DC2.4 cell line.

METHODS

DC2.4 cell line was cultured in complete RPMI 1640 medium, whose morphology was observed with optical microscope and the intracellular structures with transmission electron microscope. Flow cytometry was performed to analyze the surface markers of the cells, including MHC-II, CD86 and CD40, and RelB mRNA expression was detected by RT-PCR.

RESULTS

Under optical microscope, the cells appeared irregular in shape with obvious dendritic cell processes, and electron microscopy revealed homogenous fat drops and phagocytic vesicles in the cytoplasm. Flow cytometry demonstrated low expression levels of MHC-II and CD40, but high level of CD86 molecules. Low-level expression of RelB mRNA was detected by RT-PCR, resembling its expression level in bone marrow-derived DC with immature phenotype.

CONCLUSION

DC2.4 is a mouse bone marrow dendritic cell line with strong phagocytic capacity, and the low expression of both RelB gene and surface CD40 molecules suggests an immature dendritic cell line.

[RelB gene expression in murine bone marrow-derived mature and immature dendritic cells]

AIM

To explore the expression of avian reticuloendotheliosis viral(v-rel) oncogene-related B (RelB) mRNA in vitro in murine mature and immature myeloid dendritic cells (DCs).

METHODS

The bone marrow was collected from the femur and tibias of C57BL/6 mice in sterile condition. Bone marrow precursors were cultured with recombinant mouse granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and interleukin-4 (rmIL-4) to produce immature DCs. Immature DCs were stimulated by LPS 18 h before the end of culture to become mature. DCs' phenotype was detected by flow cytometry (FCM). RelB expression and protein level were determined by RT-PCR and immunofluorescence staining.

RESULTS

The expression level of co-stimulatory molecules (CD86 and CD40) and MHC-II class molecule were low in immature DCs, whereas high in mature DCs. RelB expression was significantly higher in mature DCs than in immature DCs (P<0.01).

CONCLUSION

RelB expression is closely associated with the maturative situation of DCs. Inhibition of RelB expression in DCs may induce tolerogenic DCs.

[Value of the antigen with molecular mass of 32 000 in immunodiagnosis of Angiostrongylus cantonensis]

OBJECTIVE

To evaluate the specificity and sensitivity of immunodiagnosis with the antigen with molecular mass of 32 000 of Angiostrongyliasis cantonensis(AC32).

METHODS

The major antigenic protein AC32 was purified from the antigens of A.cantonensis adult worm by electroelution from SDS-polyacrylamide gels. AC32-enzyme linked immunosorbent assay (ELISA) and adult worm antigen (AWA)-ELISA were used to detect the specific IgG in the sera of normal rats (n=5) and rats with angiostrongyliasis (n=61), sera of healthy individuals (n=50) and patients (n=50) with angiostrongyliasis, schistosomiasis and other parasitosis.

RESULTS

The positivity rate in AC32-ELISA of the sera from rats with angiostrongyliasis was 100%; without false positive results or cross reaction between AC32 and the sera of the normal control and patients infected with parasites other than A.cantonensis.

CONCLUSION

AC32 of A.cantonensis is a valuable candidate antigen for immunodiagnosis of angiostrongyliasis with high sensitivity and specificity.

[Preparation of time-resolved fluoroimmunoassay kit for human alpha-fetoprotein detection]

OBJECTIVE

To prepare time-resolved fluoroimmunoassay (TRFIA) kit for detecting human alpha-fetoprotein (hAFP).

METHODS

Sandwich TRFIA kit for hAFP detection was developed using monoclonal antibody of anti-AFP.

RESULTS

AFP-TRFIA kit was capable of detecting AFP within the range of 1-1 000 U/ml with sensitivity of 0.17 U/ml and without cross-reactivity with CEA, CA12-5, CA15-3, or CA19-9. The intra- and inter-assay coefficients of variation were (3.3-5.9)% and (3.7-6.5)%, respectively. The prepared AFP-TRFIA reagent could withstand preservation at 4 degrees celsius; for 1 year and at 37 degrees celsius; for 7 days with the cutoff value of 12 U/ml in healthy subjects (n=426). The correlation coefficient of the detection results between this kit and commercially available AFP kit (Wallac OY, Finland) for 60 blood samples was 0.995.

CONCLUSION

The prepared TRFIA kit for hAFP detection meets the demand of clinical application with good sensitivity, precision, specificity, stability and accuracy.

Serial monitoring of immunological parameters following human hand transplant

BACKGROUND

Although early successes have been achieved in human hand transplant, the changes of immunological parameters in the recipients and their relations to clinical events were not yet known.

METHODS

In two patients undergoing hand transplantation, we prospectively determined lymphocyte subsets using flow cytometry as well as the serum levels of interleukin (IL)-2, IL-10, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma using enzyme linked immunosorbent assays during the first 6 months after transplantation.

RESULTS

The decreases in CD, CD, CD T cell, the activated T cell (CD/CD, CD/HLA-DR(+)) as well as IL-2, IFN-gamma and corresponding significant peak in IL-10 in human hand transplant during the first post-transplant week were observed. Then these parameters recovered to the pre-transplant level except for an even higher level of CD T cell. The low CD/CD ratio was been maintained constantly. After 7 wk, IL-2, IFN-gamma, and IL-10 decreased to be maintained at a low or undetectable level except for slight increase in IL-10 at post-transplant month 5. There are no significant variation in TNF-alpha early after transplant. After 3 months, IL-10 was not detected again.

CONCLUSIONS

The immunosuppressive agents had significantly effects on the immunological status in human hand transplant recipients. These profiles of immunological parameters would be useful data for the future immunomonitoring in human hand transplant recipients.

Effect of dosage of anticancer agents during transcatheter arterial chemoembolization on T cell subsets in patients with hepatocellular carcinoma

OBJECTIVE

To investigate the effects of the dosage of anticancer agents during transcatheter arterial chemoembolization (TACE) on the T cell subsets in patients with hepatocellular carcinoma (HCC).

METHODS

Thirty-six patients with unresectable HCC were randomly divided into 2 groups to receive superselective TACE. Patients in group A (n=18) received low-dose (2-4 mg) mitomycin C (MMC) as the anticancer drug when the tumor was less than 5 cm in diameter; when the tumor ranged from 5 and 8 cm in diameter, 4-6 mg MMC along with 10 mg epirubicin (EPI) was given, and in cases of even larger tumors, 6-8 mg MMC, 10 mg EPI and 100 mg CBP were prescribed. Conventional chemotherapy regimen constituted by 10 mg MMC, 40 mg PI and 300 mg CBP was adopted in group B (n=18). The peripheral blood T cell subsets including CD3(+), CD4(+), CD8(+), NK, CD4(+)/CD8(+) ratio, CD4(+)CD45(+), CD4(+)CD29(+), CD8(+)CD28(+) and CD8(+)CD28- were measured by flow cytometry in both groups before and one week after treatment.

RESULTS

The T cell subsets were comparable in the 2 groups before the treatment. After TACE, no significant changes occurred in CD3(+), CD4(+), CD8(+), NK, CD4(+)/CD8(+), CD4(+)CD29(+) or CD8(+)CD28- cells in group A, while significant decrease in CD4(+)CD45(+) and increase in CD8(+)CD28(+) cells were observed (P<0.05 and P<0.001, respectively). In group B, CD4(+) and CD4(+)CD29(+) levels, together with CD4(+)/CD8(+) ratio, were significantly lower than those before treatment (P<0.05), but CD8(+) and CD8(+)CD28- subsets were significantly higher (P<0.05).

CONCLUSIONS

The cellular immune function of HCC patients is significantly impaired by anticancer drugs for TACE at conventional dose, while low-dose of the drugs may enhance the cellular immune function.

[Analysis of CD8(+) and CD8(+)CD28(-) cell subsets in patients with hepatocellular carcinoma]

OBJECTIVE

To study the expression of the costimulatory molecule CD28 on peripheral blood CD8(+)T cells from patients with hepatocellular carcinoma (HCC).

METHOD

The expression of CD28 on CD8(+), CD8(+)CD28(-)- and CD8(+)CD28(+) cell subsets in the peripheral blood obtained from 20 HCC patients and 15 healthy controls were assayed by flow cytometry.

RESULTS

The elevated percentages of CD8(+) cells, decreased percentages of CD8(+)CD28(+) cells and increased percentages of CD8(+)CD28(-)- cells were observed in the peripheral blood of HCC patients as compared with those of the control group (P<0.01). Positive correlation between the percentage of CD8(+)CD28(-)- cells and that of CD8(+) cells were found.

CONCLUSION

CD28 expression on CD8(+) T cells was aberrant in the peripheral blood of HCC patients, and the elevation of CD8(+)CD28(-)- cell number results in the increase of CD8(+) cell number.