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Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation.
J Neuroinflammation 2010; 7:68JN

Abstract

BACKGROUND

Activation of microglia, the resident macrophages of the central nervous system (CNS), is the hallmark of neuroinflammation in neurodegenerative diseases and other pathological conditions associated with CNS infection. The activation of microglia is often associated with bystander neuronal death. Nuclear factor-κB (NF-κB) is one of the important transcription factors known to be associated with microglial activation which upregulates the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (Cox-2) and other pro-inflammatory cytokines. Recent studies have focused on the role of Krüppel-like factor 4 (Klf4), one of the zinc-finger transcription factors, in mediating inflammation. However, these studies were limited to peripheral system and its role in CNS is not understood. Our studies focused on the possible role of Klf4 in mediating CNS inflammation.

METHODS

For in vitro studies, mouse microglial BV-2 cell lines were treated with 500 ng/ml Salmonella enterica lipopolysacchride (LPS). Brain tissues were isolated from BALB/c mice administered with 5 mg/kg body weight of LPS. Expressions of Klf4, Cox-2, iNOS and pNF-κB were evaluated using western blotting, quantitative real time PCR, and reverse transcriptase polymerase chain reactions (RT-PCRs). Klf4 knockdown was carried out using SiRNA specific for Klf4 mRNA and luciferase assays and electromobility shift assay (EMSA) were performed to study the interaction of Klf4 to iNOS promoter elements in vitro. Co-immunoprecipitation of Klf4 and pNF-κB was done in order to study a possible interaction between the two transcription factors.

RESULTS

LPS stimulation increased Klf4 expression in microglial cells in a time- and dose-dependent manner. Knockdown of Klf4 resulted in decreased levels of the pro-inflammatory cytokines TNF-α, MCP-1 and IL-6, along with a significant decrease in iNOS and Cox-2 expression. NO production also decreased as a result of Klf4 knockdown. We found that Klf4 can potentially interact with pNF-κB and is important for iNOS and Cox-2 promoter activity in vitro.

CONCLUSIONS

These studies demonstrate the role of Klf4 in microglia in mediating neuroinflammation in response to the bacterial endotoxin LPS.

Authors+Show Affiliations

National Brain Research Centre, Manesar, Haryana-122050, India.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20946687

Citation

Kaushik, Deepak K., et al. "Krüppel-like Factor 4, a Novel Transcription Factor Regulates Microglial Activation and Subsequent Neuroinflammation." Journal of Neuroinflammation, vol. 7, 2010, p. 68.
Kaushik DK, Gupta M, Das S, et al. Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation. J Neuroinflammation. 2010;7:68.
Kaushik, D. K., Gupta, M., Das, S., & Basu, A. (2010). Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation. Journal of Neuroinflammation, 7, p. 68. doi:10.1186/1742-2094-7-68.
Kaushik DK, et al. Krüppel-like Factor 4, a Novel Transcription Factor Regulates Microglial Activation and Subsequent Neuroinflammation. J Neuroinflammation. 2010 Oct 15;7:68. PubMed PMID: 20946687.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation. AU - Kaushik,Deepak K, AU - Gupta,Malvika, AU - Das,Sulagna, AU - Basu,Anirban, Y1 - 2010/10/15/ PY - 2010/07/08/received PY - 2010/10/15/accepted PY - 2010/10/16/entrez PY - 2010/10/16/pubmed PY - 2010/12/14/medline SP - 68 EP - 68 JF - Journal of neuroinflammation JO - J Neuroinflammation VL - 7 N2 - BACKGROUND: Activation of microglia, the resident macrophages of the central nervous system (CNS), is the hallmark of neuroinflammation in neurodegenerative diseases and other pathological conditions associated with CNS infection. The activation of microglia is often associated with bystander neuronal death. Nuclear factor-κB (NF-κB) is one of the important transcription factors known to be associated with microglial activation which upregulates the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (Cox-2) and other pro-inflammatory cytokines. Recent studies have focused on the role of Krüppel-like factor 4 (Klf4), one of the zinc-finger transcription factors, in mediating inflammation. However, these studies were limited to peripheral system and its role in CNS is not understood. Our studies focused on the possible role of Klf4 in mediating CNS inflammation. METHODS: For in vitro studies, mouse microglial BV-2 cell lines were treated with 500 ng/ml Salmonella enterica lipopolysacchride (LPS). Brain tissues were isolated from BALB/c mice administered with 5 mg/kg body weight of LPS. Expressions of Klf4, Cox-2, iNOS and pNF-κB were evaluated using western blotting, quantitative real time PCR, and reverse transcriptase polymerase chain reactions (RT-PCRs). Klf4 knockdown was carried out using SiRNA specific for Klf4 mRNA and luciferase assays and electromobility shift assay (EMSA) were performed to study the interaction of Klf4 to iNOS promoter elements in vitro. Co-immunoprecipitation of Klf4 and pNF-κB was done in order to study a possible interaction between the two transcription factors. RESULTS: LPS stimulation increased Klf4 expression in microglial cells in a time- and dose-dependent manner. Knockdown of Klf4 resulted in decreased levels of the pro-inflammatory cytokines TNF-α, MCP-1 and IL-6, along with a significant decrease in iNOS and Cox-2 expression. NO production also decreased as a result of Klf4 knockdown. We found that Klf4 can potentially interact with pNF-κB and is important for iNOS and Cox-2 promoter activity in vitro. CONCLUSIONS: These studies demonstrate the role of Klf4 in microglia in mediating neuroinflammation in response to the bacterial endotoxin LPS. SN - 1742-2094 UR - https://www.unboundmedicine.com/medline/citation/20946687/Krüppel_like_factor_4_a_novel_transcription_factor_regulates_microglial_activation_and_subsequent_neuroinflammation_ L2 - https://jneuroinflammation.biomedcentral.com/articles/10.1186/1742-2094-7-68 DB - PRIME DP - Unbound Medicine ER -