The Interaction Between β-3 Adrenergic Receptor and Peroxisome Proliferator-Activated Receptor Gamma Gene Polymorphism to Periodontal Disease in Community-Dwelling Elderly Japanese

Understanding the peroxisome proliferator-activated receptor gamma (PPAR-γ) role in periodontitis and diabetes mellitus: A molecular perspective

Periodontitis and Type 2 Diabetes Mellitus (T2DM) are chronic conditions with dysregulated immune responses. Periodontitis involves immune dysfunction and dysbiotic biofilms, leading to tissue destruction. T2DM is marked by insulin resistance and systemic inflammation, driving metabolic and tissue damage. Both conditions share activation of key pathways, including Nuclear Factor Kappa B (NF-κB), Activator Protein-1 (AP-1), and Signal Transducer and Activator of Transcription (STAT) proteins, reinforcing an inflammatory feedback loop. This review highlights the role of Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ), a transcription factor central to lipid and glucose metabolism, adipogenesis, and immune regulation. PPAR-γ activation has been shown to suppress inflammatory mediators such as Tumor Necrosis Factor Alpha (TNF-α) and Interleukin 6 (IL-6) through the inhibition of NF-κB, AP-1, and STAT pathways, thereby potentially disrupting the inflammatory-metabolic cycle that drives both diseases. PPAR-γ agonists, including thiazolidinediones (TZDs) and endogenous ligands such as 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), show promise in reducing inflammation and improving insulin sensitivity, but they are limited by adverse effects. Therapies, including Selective Peroxisome Proliferator-Activated Receptor Modulators (SPPARMs), have been developed to offer a more targeted approach, allowing for selective modulation of PPAR-γ activity to retain its anti-inflammatory benefits while minimizing their side effects. By integrating insights into PPAR-γ's molecular mechanisms, this review underscores its therapeutic potential in mitigating inflammation and enhancing metabolic control.

Inside the Biology of the β3-Adrenoceptor

Since the first discovery in 1989, the β3-adrenoceptor (β3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The β3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the β3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the β3-Ars' discovery, with focus on the β3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the β3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of β3-AR modulation in cancer reality.

Evidence Linking PPARG Genetic Variants with Periodontitis and Type 2 Diabetes Mellitus in a Brazilian Population

The peroxisome proliferator-activated receptor gamma (PPARG) gene encodes a transcription factor involved in the regulation of complex metabolic and inflammatory diseases. We investigated whether single nucleotide polymorphisms (SNPs) and haplotypes of the PPARG gene could contribute with susceptibility to develop periodontitis alone or together with type 2 diabetes mellitus (T2DM). Moreover, we evaluated the gene-phenotype association by assessing the subjects' biochemical and periodontal parameters, and the expression of PPARG and other immune response-related genes. We examined 345 subjects with a healthy periodontium and without T2DM, 349 subjects with moderate or severe periodontitis but without T2DM, and 202 subjects with moderate or severe periodontitis and T2DM. PPARG SNPs rs12495364, rs1801282, rs1373640, and rs1151999 were investigated. Multiple logistic regressions adjusted for age, sex, and smoking status showed that individuals carrying rs1151999-GG had a 64% lower chance of developing periodontitis together with T2DM. The CCGT haplotype increased the risk of developing periodontitis together with T2DM. The rs1151999-GG and rs12495364-TC were associated with reduced risk of obesity, periodontitis, elevated triglycerides, and elevated glycated hemoglobin, but there was no association with gene expression. Polymorphisms of the PPARG gene were associated with developing periodontitis together with T2DM, and with obesity, lipid, glycemic, and periodontal characteristics.

Waistline to the gumline: Relationship between obesity and periodontal disease-biological and management considerations

Obesity is a pandemic and periodontitis is the sixth most prevalent disease in the world. These two noncommunicable diseases share several risk determinants. Epidemiologic evidence from the last 2 decades has established an increase in periodontitis prevalence in obese and overweight individuals. Biologic mechanisms potentially linking obesity and periodontal disease are adiposity-associated hyperinflammation, microbial dysbiosis, altered immune response, specific genetic polymorphisms, and increased stress. However, because of the lack of longitudinal interventional studies and randomized clinical trials, there is insufficient evidence to determine the cause-effect relationship between these two diseases. Despite this, the negative impact of obesity on oral health is well established. Several logistic and physiologic complications are associated with treating obese patients in a dental setting, and it requires an interprofessional team approach. Oral health care professionals need to be aware of the specific management considerations while rendering for this cohort, including modified practice facility and equipment, tailored supportive periodontal therapy, and heightened precaution during conscious sedation and surgical procedures.

The association of periodontal diseases with metabolic syndrome and obesity

Periodontitis is a multifactorial chronic inflammatory disease associated with dysbiotic plaque biofilms and characterized by progressive destruction of the tooth-supporting apparatus. Globally, it is estimated that 740 million people are affected by its severe form. Periodontitis has been suggested to be linked to obesity and metabolic syndrome. Obesity, defined as excessive fat accumulation, is a complex multifactorial chronic inflammatory disease, with a high and increasing prevalence. Metabolic syndrome is defined as a cluster of obesity, dyslipidemia, hypertension, and dysglycemia. Obesity, metabolic syndrome and periodontitis are among the most common non-communicable diseases and a large body of evidence from epidemiologic studies supports the association between these conditions. Extensive research has established plausible mechanisms to explain how these conditions can negatively impact each other, pointing to a bidirectional adverse relationship. At present there is only limited evidence available from a few intervention studies. Nevertheless, the global burden of periodontitis combined with the obesity epidemic has important clinical and public health implications for the dental team. In accordance with the common risk factor approach for tackling non-communicable diseases, it has been proposed that oral healthcare professionals have an important role in the promotion of periodontal health and general well-being through facilitation of healthy lifestyle behaviours.

Interaction between beta-3 adrenergic receptor genotype and environmental factors on periodontal progression

OBJECTIVES

The purpose of this longitudinal study was to evaluate the relationship between beta-3 adrenergic receptor polymorphism and environmental factors such as smoking on periodontal disease by considering effect modification.

MATERIALS AND METHODS

A total of 294 subjects who participated in all follow-up surveys over the 6-year study period were analysed. After dividing subjects into tertiles according to the number of years exposed to smoking, we conducted Poisson regression analysis to compare the incidence rate ratio (IRR) for periodontal disease events during the 6-year study period with beta-3 adrenergic receptor genotype (1: Arg allele carriers, 2: Arg allele non-carriers) for each tertile adjusted for other four variables.

RESULTS

The number of years exposed to smoking (mean ± standard deviation) for the 1st, 2nd and 3rd tertiles was 0 ± 0, 20.1 ± 9.1 and 45.3 ± 7.7 years, respectively. The IRRs ± SE were 0.89 ± 0.08 (p = 0.218) for the 1st tertile, 1.93 ± 0.36 (p < 0.001) for the 2nd tertile and 2.56 ± 0.23 (p < 0.001) for the 3rd tertile.

CONCLUSION

There was a clear dose-response relationship between beta-3 adrenergic receptor genotype and periodontal disease progression based on the number of years exposed to smoking.

MAEA rs6815464 polymorphism and periodontitis in postmenopausal Japanese females: A cross-sectional study

OBJECTIVES

Macrophage erythroblast attacher (MAEA) is a membrane protein that regulates the development of mature macrophages by mediating attachment with erythroblasts. A polymorphism rs6815464 (C/G) in MAEA gene was reported to be associated with type II diabetes. Along with diabetes, osteoporosis shows an increased prevalence in postmenopausal females, and both diseases have been reported to be associated with periodontitis. Therefore, we explored the relevance of the MAEA polymorphism to periodontitis, bone mineral density (BMD) and haemoglobin A1c (HbA1c).

DESIGN

This was a cross-sectional study with the final sample comprised of 344 postmenopausal Japanese females. Probing pocket depth (PPD) and clinical attachment level (CAL) were measured. Genotype was determined by TaqMan assay. Blood biochemical parameters and BMD of the lumbar spine were evaluated.

RESULTS

No differences were found in age, body mass index, HbA1c, BMD, number of teeth, bone metabolism parameters between the genotypes. Mean CAL and percentage of sites with PPD or CAL ≥ 5 mm were higher in the G-allele carriers than in the non-carriers. Multiple logistic regression analyses revealed that G-allele carriage was associated with severe periodontitis (odds ratio = 3.73, 95% CI = 1.36-10.19).

CONCLUSION

Our results suggested that the MAEA gene polymorphism was independently associated with severe periodontitis.

Beta3 adrenergic receptor stimulation in human macrophages inhibits NADPHoxidase activity and induces catalase expression via PPARγ activation

The beta3 adrenergic receptor (β3-AR) stimulation plays a protective role against preterm labor by blocking myometrial contraction, cytokine production, remodeling and apoptosis. We previously demonstrated that macrophage-induced ROS production in the myometrium was a key element leading to the induction of all these labor-associated features. We thus aimed to investigate if the β3-AR could be expressed in human macrophages and could trigger its protective role in the myometrium by directly inhibiting ROS production. Using lipopolysaccharide (LPS)-stimulated myometrial samples and cell co-culture experiments, we demonstrated that β3-AR stimulation inhibits the activation of the NADPH oxidase, leading to the subsequent inhibition of ROS production by macrophages. This antioxidant effect was associated with a potent anti-inflammatory response in macrophages. Furthermore, we observed that β3-AR leads to the expression of catalase not only in macrophages but also in myometrial cells, thereby preventing the transactivation of myometrial cells by hydrogen peroxide. Pharmacological experiments allowed us to demonstrate that these effects were driven by an Erk1/2-mediated activation of the antioxidant transcription factor PPARγ. These results suggest that β3-AR protective effects in the myometrium could be due to its dual antioxidant properties. Further, the effects observed in a macrophage could highlight new applications in chronic inflammatory diseases.

Influence of the Periodontal Disease, the Most Prevalent Inflammatory Event, in Peroxisome Proliferator-Activated Receptors Linking Nutrition and Energy Metabolism

Periodontal disease is considered one of the main pathologic diseases occurring in humans. Its pathologic process involves inflammatory reactions producing periodontal bone resorption and the tooth loss. But some patients do not present an evident clinical inflammation with bone resorption, and in others, the inflammation is prominent without bone resorption. A key question could be to investigate a different way of responding to aggression. Inflammation requires a complex intracellular metabolic process, starting with the harmful recognition and activation of the inflammasome, continues the energy supply with the alteration of oxidative stress conditions, and finishes with the elimination of the aggression with autophagy/apoptosis mechanisms, then concludes with recovery. Peroxisome proliferator-activated receptors (PPARs) are essential molecules produced in inflammation, and its genes and its activation have been related to periodontal disease. Also, an important aspect is the influence of PPARs in bone metabolism; the main periodontitis symptom is bone loss and PPARγ activation that can downregulate the bone resorption in experimental periodontitis, PPARγ-coated titanium dental implant surfaces could carry the antiinflammatory gene and restrain inflammation. PPARs could be one of the meeting background points with atherosclerosis/cardiovascular disease, diabetes and metabolic syndrome showing a modified proinflammatory statement such as it is described in periodontitis.