HIF-1α–Mediated Upregulation of TASK-2 K⁺ Channels Augments Ca²⁺ Signaling in Mouse B Cells under Hypoxia

Shin, Dong Hoon,Lin, Haiyue,Zheng, Haifeng,Kim, Kyung Su,Kim, Jin Young,Chun, Yang Sook,Park, Jong Wan,Nam, Joo Hyun,Kim, Woo Kyung,Zhang, Yin Hua,Kim, Sung Joon American Association of Immunologists 2014 Journal of Immunology Vol. No.

<P>The general consensus is that immune cells are exposed to physiological hypoxia in vivo (PhyO(2),2-5% P-O2). However, functional studies of B cells in hypoxic conditions are sparse. Recently, we reported the expression in mouse B cells of TASK-2, a member of pH-sensitive two-pore domain K+ channels with background activity. In this study, we investigated the response of K+ channels to sustained PhyO(2) (sustained hypoxia [SH], 3% P-O2 for 24 h) in WEHI-231 mouse B cells. SH induced voltage-independent background K+ conductance (SH-K-bg) and hyperpolarized the membrane potential. The pH sensitivity and the single-channel conductance of SH-K-bg were consistent with those of TASK-2. Immunoblotting assay results showed that SH significantly increased plasma membrane expressions of TASK-2. Conversely, SH failed to induce any current following small interfering (si)TASK-2 transfection. Similar hypoxic upregulation of TASK-2 was also observed in splenic primary B cells. Mechanistically, upregulation of TASK-2 by SH was prevented by si hypoxia-inducible factor-1 alpha (HIF-1 alpha) transfection or by YC-1, a pharmacological HIF-la inhibitor. In addition, TASK-2 current was increased in WEHI-231 cells overexpressed with 02-resistant HIF-1 alpha. Importantly, [Ca2+](c) increment in response to BCR stimulation was significantly higher in SH-exposed B cells, which was abolished by high K+-induced depolarization or by siTASK-2 transfection. The data demonstrate that TASK-2 is upregulated under hypoxia via HIF-1 alpha dependent manner in B cells. This is functionally important in maintaining the negative membrane potential and providing electrical driving force to control Ca2+ influx.</P>

Identification of the large-conductance background K+ channel in mouse B cells as TREK-2.

Zheng, Haifeng,Nam, Joo Hyun,Pang, Bo,Shin, Dong Hoon,Kim, Ji Seon,Chun, Yang-Sook,Park, Jong-Wan,Bang, Hyowon,Kim, Woo Kyung,Earm, Yung E,Kim, Sung Joon American Physiological Society 2009 American journal of physiology. Cell physiology Vol.297 No.1

<P>Mouse B cells and their cell line (WEHI-231) express large-conductance background K(+) channels (LK(bg)) that are activated by arachidonic acids, characteristics similar to TREK-2. However, there is no evidence to identify the molecular nature of LK(bg); some properties of LK(bg) were partly different from the reported results of TREK type channels. In this study, we compared the properties of cloned TREK-2 and LK(bg) in terms of their sensitivities to ATP, phosphatidylinositol 4,5-bisphosphate (PIP(2)), intracellular pH (pH(i)), and membrane stretch. Similar to the previous findings of LK(bg), TREK-2 showed spontaneous activation after membrane excision (i-o patch) and were inhibited by MgATP or by PIP(2). The inhibition by MgATP was prevented by wortmannin, suggesting membrane-delimited regulation of TREKs by phosphoinositide (PI) kinase. The same was observed with the property of LK(bg); the activation of TREK-2 by membrane stretch was suppressed by U73122 (PLC inhibitor). As with the known properties of TREK-2, LK(bg) were activated by acidic pH(i) and inhibited by PKC activator. Finally, we confirmed the expression of TREK-2 in WEHI-231 by using RT-PCR and immunoblot analyses. The amplitude of background K(+) current and the TREK-2 expression in WEHI-231 were commonly decreased by genetic knockdown of TREK-2 using small interfering RNA. The downregulation of TREK-2 attenuated Ca(2+)-influx induced by arachidonic acid in WEHI-231. As a whole, these results strongly indicate that TREK-2 encodes LK(bg) in mouse B cells. We also newly suggest that the low activity of TREK-2 in intact cells is due to the inhibition by intrinsic PIP(2).</P>

Inhibition of store-operated Ca²⁺ entry channels and K⁺ channels by caffeic acid phenethylester in T lymphocytes

Nam, Joo Hyun,Shin, Dong Hoon,Zheng, Haifeng,Kang, Jae Seung,Kim, Woo Kyung,Kim, Sung Joon Elsevier 2009 european journal of pharmacology Vol.612 No.1

<P><B>Abstract</B></P><P>The increase of cytoplasmic Ca<SUP>2+</SUP> concentration (Δ[Ca<SUP>2+</SUP>]<SUB>c</SUB>) in response to antigenic stimulation is a critical step of signals activating immune responses. In addition, the voltage-gated K<SUP>+</SUP> channels (Kv) in T lymphocytes draw attention as an effective target of immune-modulation. Caffeic acid phenethyl ester (CAPE), an active component of propolis, shows strong anti-inflammatory effects and T cell suppression. Although various mechanisms have been suggested for the action of CAPE, the effects of CAPE on intracellular Ca<SUP>2+</SUP> signaling and ion channels are unknown. Here we investigated the effects of CAPE on Δ[Ca<SUP>2+</SUP>]<SUB>c</SUB>, Ca<SUP>2+</SUP>-release activated Ca<SUP>2+</SUP> current (<I>I</I><SUB>CRAC</SUB>), and Kv current (<I>I</I><SUB>Kv</SUB>) in Jurkat T cells, and on Ca<SUP>2+</SUP>-activated K<SUP>+</SUP> channel current (<I>I</I><SUB>SK4</SUB>) overexpressed in HEK-293 cells. <I>I</I><SUB>CRAC</SUB> was induced by dialyzing T cells and Orai1/STIM1 overexpressing HEK293 cells with InsP<SUB>3</SUB>/BAPTA-containing pipette solution. CAPE concentration-dependently decreased both T cell receptor (CD3)- and thapsigargin-induced Δ[Ca<SUP>2+</SUP>]<SUB>c</SUB>. The phosphorylation of PLCγ<SUB>1</SUB> by CD3 stimulation was not affected by CAPE. <I>I</I><SUB>CRAC</SUB> was almost completely blocked by 25?μM CAPE. CAPE also inhibited the <I>I</I><SUB>Kv</SUB> and <I>I</I><SUB>SK4</SUB>. Albeit the strong inhibition of Ca<SUP>2+</SUP> influx via CRAC, the suppression of IL-2 secretion by CAPE was similarly observed in human peripheral T cells when the CRAC pathway was circumvented by ionomycin. Although the unspecific inhibition of ion channels by CAPE suggested an intriguing mechanism, the effects of CAPE on signaling pathways other than <I>I</I><SUB>CRAC</SUB> seem to play dominant roles in the immunomodulation by CAPE.</P>

Antiserum Preparation of Recombinant Sweet Potato Latent Virus-Lotus (SPLV-Lotus) Coat Protein and Application for Virus-Infected Lotus Plant Detection

Zhen He,Tingting Dong,Wen Chen,Tielin Wang,Haifeng Gan,LiangJun Li 한국식물병리학회 2020 Plant Pathology Journal Vol.36 No.6

Lotus is one of the most important aquatic vegetables in China. Previously, we detected sweet potato latent virus from lotus (SPLV-lotus) and found that it has highly significant sequence diversity with SPLV-sweet potato isolates (SPLV-sp). Here, we developed serological methods for the detection of SPLV-lotus in Chinese lotus cultivation areas. Based on the high sensitivity of SPLV-lotus coat protein antiserum, rapid, sensitive and large-scale diagnosis methods of enzyme-linked immunosorbent assay (ELISA) and dot blot in lotus planting area were developed. The established ELISA and dot blot diagnostic methods can be used to detect SPLVlotus from samples successfully. And our results also showed that the SPLV-lotus and sweet potato isolates appeared clearly distinction in serology. Our study provides a high-throughput, sensitive, and rapid diagnostic method based on serology that can detect SPLV on lotus, which is suggested to be included in viral disease management approach due to its good detection level.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Liu, Qihui,Tian, Yuan,Zhao, Xiangfeng,Jing, Haifeng,Xie, Qi,Li, Peng,Li, Dong,Yan, Dongmei,Zhu, Xun Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-$Gu{\acute{e}}rin$) activates disabled $na{\ddot{i}}ve$ macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-${\alpha}$), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-$1{\beta}$), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-${\beta}$) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Qihui Liu,Xun Zhu,Yuan Tian,Xiangfeng Zhao,Haifeng Jing,Qi Xie,Peng Li,Dong Li,Dongmei Yan 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-Guérin) activates disabled naïve macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-1β), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-β) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

Microalgal and cyanobacterial strains used for the bio sorption of copper ions from soil and wastewater and their relative study

Shah Zada,Saleem Raza,Sikandar Khan,Arshad Iqbal,Zhang Kai,Aftab Ahmad,Midrar Ullah,Mohib Kakar,Pengcheng Fu,Haifeng Dong,Zhang Xueji 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

Heavy metals and other organic pollutants are the hazardous materials causing soil and water pollution,hence, bioremediation of these components is a matter of concern for environmental biotechnologists. Twenty one microalgal and cyanobacterial strains were evaluated for removal of copper from aqueoussolutions and soil containing 10 ppm copper. 5 out of 21 strains have shown comparatively higher toleranceto copper stress. The biosorption capabilities of all the five strains were assessed using techniqueslike ultraviolet (UV) spectrophotometers, scanning electron microscope (SEM), inductively coupledplasma mass spectrometry (ICP-MS), and confocal Microscopy. It was found that the five selected strainscould grow normally upon incubating with 20 ppm of Cu. Copper removal efficiencies of these microalgae(S. obliquus, A. braunii, C. fusca, L. JSC-1 and C. saccharophila in water were 99.9, 99.3, 97, 96.7, and 96%,while for soil was 73, 75, 71, 70, 68%, respectively. A minor leakage of nucleic acid and protein weredetected with time. Furthermore, no any visible morphological changes were observed after six daysof treatment, while minor changes were noticed after 12 days in water, and severe morphological deformationsoccurred after 24 days of bioremediation in soil. Our findings reveal that the selected microalgalstrains have high potential for Cu bioremediation at certain concentration for 12 days exposure fromwater and 24 from soil.