Correction: LRRK2 kinase plays a critical role in manganese-induced inflammation and apoptosis in microglia

Long-term exposure to elevated levels of manganese (Mn) causes manganism, a neurodegenerative disorder with Parkinson’s disease (PD)-like symptoms. Increasing evidence suggests that leucine-rich repeat kinase 2 (LRRK2), which is highly expressed in microglia and macrophages, contributes to the inflammation and neurotoxicity seen in autosomal dominant and sporadic PD. As gene-environment interactions have emerged as important modulators of PD-associated toxicity, LRRK2 may also mediate Mn-induced inflammation and pathogenesis. In this study, we investigated the role of LRRK2 in Mn-induced toxicity using human microglial cells (HMC3), LRRK2-wild-type (WT) and LRRK2-knockout (KO) RAW264.7 macrophage cells. Results showed that Mn activated LRRK2 kinase by phosphorylation of its serine residue at the 1292 position (S1292) as a marker of its kinase activity in macrophage and microglia, while inhibition with GSK2578215A (GSK) and MLi-2 abolished Mn-induced LRRK2 activation. LRRK2 deletion and its pharmacological inhibition attenuated Mn-induced apoptosis in macrophages and microglia, along with concomitant decreases in the pro-apoptotic Bcl-2-associated X (Bax) protein. LRRK2 deletion also attenuated Mn-induced production of reactive oxygen species (ROS) and the pro-inflammatory cytokine TNF-α. Mn-induced phosphorylation of mitogen-activated protein kinase (MAPK) p38 and ERK signaling proteins was significantly attenuated in LRRK2 KO cells and GSK-treated cells. Moreover, inhibition of MAPK p38 and ERK as well as LRRK2 attenuated Mn-induced oxidative stress and cytotoxicity. These findings suggest that LRRK2 kinase activity plays a critical role in Mn-induced toxicity via downstream activation of MAPK signaling in macrophage and microglia. Collectively, these results suggest that LRRK2 could be a potential molecular target for developing therapeutics to treat Mn-related neurodegenerative disorders.

After this article [1] was published, concerns were raised about Figs 4 and 9. Specifically: The LRRK2 KO β-actin panel in Fig 4A appears similar to the LRRK2 WT p38 panel in Fig 9A. The authors stated that the above concern was due to errors made during preparation of the figures and stated that the panel in Fig 9A was correct. The authors provided the underlying panel and accompanying quantification data for Fig 4A (S1 File and S2 File) along with accompanying underlying data for Fig 9A (S3 File and S4 File). The above concern is therefore resolved. In reviewing this matter, PLOS noted that the primary data were not provided with the published article [1] contrary to the Data Availability Statement. The authors stated that not all the underlying data for this article remain available, and therefore this article does not comply with the PLOS data availability policy. In light of the above concern pertaining to data availability, the PLOS ONE Editors issue this Expression of Concern. Supporting information S1 File Fig 4A β-actin uncropped blot. (PPTX) Click here for additional data file. S2 File Fig 4B Quantitative Data. (PZFX) Click here for additional data file. S3 File Fig 9A p-38 uncropped blot. (PPTX) Click here for additional data file. S4 File Fig 9A Quantitative Data. (PZFX) Click here for additional data file.