Ckip-1 Mediates P. gingivalis–Suppressed Cementoblast Mineralization

Porphyromonas gingivalis is responsible for the destruction of cementum in patients with periodontitis and periapical periodontitis. However, research about the effects of P. gingivalis on cementoblast mineralization and the underlying mechanism is still lacking. Casein kinase 2 interacting protein 1 (Ckip-1) is a scaffold protein that interacts with various proteins and signals to regulate different cell functions, such as cell morphology, apoptosis, and differentiation. In this study, we verified the suppressive effects of P. gingivalis and lipopolysaccharide (Pg-LPS) on OCCM-30 mineralization. We also showed that Ckip-1 gradually decreased during OCCM-30 mineralization but increased with the aggravation of Pg-induced inflammation. However, it remained unchanged when cells were stimulated with Pg-LPS, regardless of the concentration and incubation time. Then, more cellular cementum and enhanced Osterix expression were observed in Ckip-1 knockout mice when compared with the wild-type mice. Meanwhile, Ckip-1 silencing significantly enhanced cementoblast mineralization with or without P. gingivalis–associated inflammation. The trend was opposite when Ckip-1 was overexpressed. Finally, we found that the p38, Akt, and Wnt pathways were activated, while the Erk1/2 pathway was inhibited when Ckip-1 was silenced. The opposite results were also observed in the Ckip-1 overexpression group. Furthermore, we proved that cell mineralization was weakened when p38, Akt inhibitors were applied and strengthened when the Erk1/2 pathway was inhibited. In summary, Ckip-1 is upregulated under P. gingivalis–induced inflammation and negatively regulates cementoblast mineralization partially through mitogen-activated protein kinases and Akt signaling pathways, which may contribute to the restoration of cementum destroyed by P. gingivalis.

MicroRNA (miR)-355 Suppressed Small Cell Lung Cancer Cell Metastasis via Regulating P38 Mitogen-Activated Protein Kinases (MAPKs) Signaling

MicroRNA (miR)-355 was reported to mediate p38 mitogen-activated protein kinases (MAPKs) signaling, which exerted an effect on cell invasion and metastasis. But whether miR-355 could inhibit small cell lung cancer cell line H446 cell metastasis by regulating p38 MAPKs signaling needs further study. H446 cells were cultured to establish miR-355 overexpression group and blank group. The expression of MT1-MMP, the activity and migration of H446 cells were evaluated. Further, the ability of invasion, the level of p-p38 MAPKs and the activity degree of MT1-MMP were observed in H446 cells. MT1-MMP was mainly expressed on the cell membrane. miR-355 overexpression significantly decreased cellular viability and reduced MT1-MMP and p-p38 MAPKs levels relative to the blank group without influencing p38 MAPKs level. In addition, miR-355 overexpression suppressed cell migration and invasive ability in H446 cells. Finally, miR-355 overexpression reduced pro-MMP and MMP-2 activity in H446 cells. miR-355 overexpression suppressed H446 cell metastasis through regulating P38 MAPKs signaling.

La participación de las cinasas de proteínas activadas por mitógenos en la señalización por hormonas en Arabidopsis thaliana L.

Los módulos de señalización mediados por cinasas de proteína activadas por mitógenos o MAPK (Mitogen-Activated Protein Kinases, por sus siglas en inglés), participan en la transducción de distintos tipos de señales mediante la fosforilación de diversos sustratos como las enzimas, componentes estructurales, factores transcripcionales e incluso otras cinasas. Estos módulos están conformados por miembros de tres familias de proteinas diferentes, denominadas MAPK, MEK o MAPKK (MAP cinasa cinasa) y MEKK o MAPKKK (MAP cinasa cinasa cinasa), que se activan de manera secuencial por la fosforilación de residuos de aminoácidos localizados en el dominio de activación. Mediante cascadas de MAPK las células responden a distintos tipos de estrés, además, se ha demostrado que las hormonas vegetales también ejercen su efecto en los programas de crecimiento y desarrollo de las plantas a través de estas mismas vías de señalización. En este trabajo se presenta un panorama general de los diversos mecanismos de señalización por hormonas en Arabidopsis thaliana L., en los que están involucradas cascadas de señalización de MAPK.