Role of PCSK9 in the Development of Mouse Periodontitis Before and After Treatment: A Double-Edged Sword.

Periodontitis is a highly prevalent infectious disease associated genetically with coronary heart disease (CHD). The effects of proprotein convertase subtilisin/kexin type 9 (PCSK9), a critical regulator of CHD, on periodontitis have not been studied to date. Here, we found that PCSK9 expression was increased in periodontitis patients and Porphyromonas gingivalis (Pg)-infected mice. Loss of PCSK9 attenuated Pg-induced periodontal bone loss in mice. First, PCSK9 deficiency reduced the release of inflammation-associated cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin 1ß, in vitro and in vivo. Second, its deficiency enhanced Pg and endotoxin clearance during Pg invasion in part by upregulating CD36 and low-density lipoprotein receptor (LDLR), respectively. However, after berberine treatment, periodontal bone regeneration in the PCSK9 knockout group was significantly lower than that in wild-type. This was because PCSK9 overexpression promoted osteogenic differentiation of periodontal ligament stem cells (PDLCs) prechallenged by TNF-α. Furthermore, PCSK9 could rescue PDLC osteogenesis by repressing the NF-κB signaling pathway by interacting with TRAF2. These results suggest that PCSK9 may be a potent drug target for treating periodontitis.

Short-term effects of meteorological factors, air pollution, and sunspot on childhood hand, foot, and mouth disease in Tianjin, China: a new time series regression, 2014-2018.

This study is aimed at defining the relationship between a set of environmental factors and childhood HFMD and then at estimating the related effect. The 16 environmental factors included meteorological, air pollution, and sunspot. A traditional TSR modified by using susceptible-infectious-recovery models and distribution lag nonlinear model was applied to estimate the short-term effects of daily environmental factors on children HFMD occurrence in 2014-2018 with adjustment of potential confounding factors. A total of 70,027 children aged 0-15 years with HFMD were enrolled. No significant effect was observed for daily sunspot numbers and average visibility. We found positive effects of the ambient average temperature, with an approximately m-shaped curve of the overall cumulative relationship, peaking at 25.6 °C with a relative risk (RR) of 1.45 (95% confidence intervals 1.21-1.73). The largest RR value of hot effect was achieved on the current day and then decreased by 2 days (total group, male group, and scatter group) or 1 day (female group and nursery group), and the effect lasted about 6 to 8 days from the lag 4 or lag 6 day. A greater association of temperature with HFMD for the female group and the scattered group was observed. This study suggests that ambient average temperature might be a risk factor for children HFMD in Tianjin. Further studies are warranted to confirm these findings.