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2 "Sang-Hee Lee"
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Berberine promotes host lipolysis to enhance antimicrobial defense against hypervirulent Klebsiella pneumoniae infection
Ju Yeong Lee, Hui-Jung Jung, Anwesha Ash, Seunghyeon Jeon, Miri Hyun, Ji Yeon Lee, Sang-Hee Lee, Hyuk Nam Kwon, Won-Ki Baek, Jichan Jang, Hyun ah Kim, Jin Kyung Kim
J. Microbiol. 2026;64(8):e2605001.   Published online August 31, 2026
DOI: https://doi.org/10.71150/jm.2605001
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AbstractAbstract PDFSupplementary Material

Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging pathogen that causes severe community-acquired infections; however, the immune mechanisms controlling intracellular hvKp have yet to be clearly defined. In this study, we investigated the therapeutic potential of berberine against hvKp infection and elucidated the underlying molecular mechanisms using macrophage cell models and in vivo zebrafish models. Berberine significantly reduced intracellular hvKp survival in macrophages and improved survival in hvKp-infected zebrafish. Berberine markedly attenuated proinflammatory cytokine production and inhibited the c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) signaling pathways. Notably, we found that hvKp exploited host lipid droplets (LD) biosynthesis to support its intracellular survival, and berberine effectively suppressed LD accumulation. Mechanistically, berberine promoted the nuclear translocation of transcription factor EB (TFEB), thereby enhancing lipolysis. Although berberine upregulated autophagy-related gene expression during hvKp infection, it did not induce lipophagy, the selective autophagic degradation of LD. Collectively, these findings indicate that berberine has potential as a therapeutic agent against hvKp infection by modulating host lipid metabolism to restrict bacterial intracellular survival.

Research Support, Non-U.S. Gov't
Purification and Characterization of NADPH-Dependent Cr(VI) Reductase from Escherichia coli ATCC 33456
Woo-Chul Bae , Han-Ki Lee , Young-Chool Choe , Deok-Jin Jahng , Sang-Hee Lee , Sang-Jin Kim , Jung-Hyun Lee , Byeong-Chul Jeong
J. Microbiol. 2005;43(1):21-27.
DOI: https://doi.org/2143 [pii]
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A soluble Cr(VI) reductase was purified from the cytoplasm of Escherichia coli ATCC 33456. The molecular mass was estimated to be 84 and 42 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis, respectively, indicating a dimeric structure. The pI was 4.66, and optimal enzyme activity was obtained at pH 6.5 and 37^oC. The most stable condition existed at pH 7.0. The purified enzyme used both NADPH and NADH as electron donors for Cr(VI) reduction, while NADPH was the better, conferring 61% higher activity than NADH. The K_m values for NADPH and NADH were determined to be 47.5 and 17.2 umol, and the V_max values 322.2 and 130.7 umol Cr(VI) min^-1mg^-1 protein, respectively. The activity was strongly inhibited by N-ethylmalemide, Ag^2+, Cd^2+, Hg^2+, and Zn^2+. The antibody against the enzyme showed no immunological cross reaction with those of other Cr(VI) reducing strains.

Journal of Microbiology : Journal of Microbiology
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