Enhanced inflammatory damage by microRNA-136 targeting Klotho expression in HK-2 cells by modulating JAK/STAT pathway

Area of Science:

• Molecular Biology
• Cell Biology
• Renal Physiology

Background:

• MicroRNA-136 (miR-136) is recognized as a tumor suppressor in glioma cells.
• Its role in regulating inflammatory responses, particularly in renal cells, remains largely unexplored.
• Kidney injury involves complex inflammatory processes that can be modulated by microRNAs.

Purpose of the Study:

• To investigate the function of miR-136 in lipopolysaccharide (LPS)-induced inflammatory damage in human kidney 2 (HK-2) cells.
• To determine if miR-136 targets Klotho and modulates inflammatory signaling pathways.
• To elucidate the specific mechanisms by which miR-136 influences renal cell viability, apoptosis, and cytokine production.

Main Methods:

• HK-2 cells were cultured and treated with LPS to induce inflammation.
• Transfection with miR-136 mimics, si-miR-136, and si-Klotho was performed.
• Dual luciferase assays were used to validate Klotho as a direct target of miR-136.
• Cell viability, apoptosis assays, and quantification of inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) were conducted.
• Expression levels of Klotho, JAK/STAT, and mTOR signaling pathway components were analyzed.

Main Results:

• LPS exposure decreased miR-136 expression while inducing inflammatory damage, reduced cell viability, and increased apoptosis and inflammatory cytokine levels.
• Overexpression of miR-136 exacerbated LPS-induced inflammatory damage, decreased cell viability, and increased apoptosis and inflammatory cytokines.
• Knockdown of miR-136 attenuated these effects.
• miR-136 was confirmed to negatively regulate Klotho expression.
• miR-136 modulated the JAK/STAT and mTOR signaling pathways, with overexpression activating them.

Conclusions:

• MiR-136 plays a pro-inflammatory role in HK-2 cells, contrary to its tumor-suppressive function in glioma.
• miR-136 likely exacerbates inflammatory damage by targeting Klotho and subsequently activating the JAK/STAT and mTOR signaling pathways.
• These findings reveal a novel mechanism of miR-136 in regulating renal inflammation and provide potential therapeutic targets.