Phenolic Compounds Known to Be Present in Lingonberry (Vaccinium vitis-idaea L.) Enhance Macrophage Polarization towards the Anti-Inflammatory M2 Phenotype

Regulation of the microglial polarization for alleviating neuroinflammation in the pathogenesis and therapeutics of major depressive disorder

Major depressive disorder (MDD), as a multimodal neuropsychiatric and neurodegenerative illness with high prevalence and disability rates, has become a burden to world health and the economy that affects millions of individuals worldwide. Neuroinflammation, an atypical immune response occurring in the brain, is currently gaining more attention due to its association with MDD. Microglia, as immune sentinels, have a vital function in regulating neuroinflammatory reactions in the immune system of the central nervous system. From the perspective of steady-state branching states, they can transition phenotypes between two extremes, namely, M1 and M2 phenotypes are pro-inflammatory and anti-inflammatory, respectively. It has an intermediate transition state characterized by different transcriptional features and the release of inflammatory mediators. The timing regulation of inflammatory cytokine release is crucial for damage control and guiding microglia back to a steady state. The dysregulation can lead to exorbitant tissue injury and neuronal mortality, and targeting the cellular signaling pathway that serves as the regulatory basis for microglia is considered an essential pathway for treating MDD. However, the specific intervention targets and mechanisms of microglial activation pathways in neuroinflammation are still unclear. Therefore, the present review summarized and discussed various signaling pathways and effective intervention targets that trigger the activation of microglia from its branching state and emphasizes the mechanism of microglia-mediated neuroinflammation associated with MDD.

Bee Pollen Phytochemicals and Nutrients as Unequaled Pool of Epigenetic Regulators: Implications for Age-Related Diseases

Bee pollen is characterized by an exceptional diversity and abundance of micronutrients and bioactive phytochemicals. This richness remains very sparsely investigated, but accumulating evidence strongly supports a promising future for bee pollen in human nutrition and medicine. Epigenetic regulation is among the most compelling biomedical topics that remain completely untapped in bee pollen and bee derivative research. In our current research, we identified numerous ubiquitous compounds that are consistently present in this matrix, regardless of its botanical and geographical origins, and that have been well studied and documented as epigenetic regulators in recent years. Given the relative newness of both bee pollen biomedical research and epigenetic studies within nutritional, pharmaceutical, and medical sciences, this review aims to bridge these valuable fields and advance related experimental investigations. To the best of our knowledge, this is the first work that has aimed to comprehensively investigate the epigenetic modulatory potential of bee pollen compounds. Our findings have also unveiled several intriguing phenomena, such as a dual effect of the same compound depending on the cellular context or the effect of some compounds on the cross-generational heritability of epigenetic traits. Although experimental studies of epigenetic regulation by bee pollen as a whole or by its extract are still lacking, our current study clearly indicates that this research avenue is very promising and worth further investigations. We hope that our current work constitutes a foundational cornerstone of future investigations for this avenue of research.

Resveratrol-driven macrophage polarization: unveiling mechanisms and therapeutic potential

Resveratrol, a polyphenolic compound known for its diverse biological activities, has demonstrated multiple pharmacological effects, including anti-inflammatory, anti-aging, anti-diabetic, anti-cancer, and cardiovascular protective properties. Recent studies suggest that these effects are partly mediated through the regulation of macrophage polarization, wherein macrophages differentiate into pro-inflammatory M1 or anti-inflammatory M2 phenotypes. Our review highlights how resveratrol modulates macrophage polarization through various signaling pathways to achieve therapeutic effects. For example, resveratrol can activate the senescence-associated secretory phenotype (SASP) pathway and inhibit the signal transducer and activator of transcription (STAT3) and sphingosine-1-phosphate (S1P)-YAP signaling axes, promoting M1 polarization or suppressing M2 polarization, thereby inhibiting tumor growth. Conversely, it can promote M2 polarization or suppress M1 polarization by inhibiting the NF-κB signaling pathway or activating the PI3K/Akt and AMP-activated protein kinase (AMPK) pathways, thus alleviating inflammatory responses. Notably, the effect of resveratrol on macrophage polarization is concentration-dependent; moderate concentrations tend to promote M1 polarization, while higher concentrations may favor M2 polarization. This concentration dependence offers new perspectives for clinical treatment but also underscores the necessity for precise dosage control when using resveratrol. In summary, resveratrol exhibits significant potential in regulating macrophage polarization and treating related diseases.

Lingonberry (Vaccinium vitis-idaea L.) Fruit Phenolic Bioactivities-A Review of In Vitro and In Vivo Human Studies

This review is focused on the effects of lingonberry (Vaccinium vitis-idaea L.) fruit phenolic compounds in human in vitro cells and in vivo clinical studies. Studies with lingonberries, lingonberry juice/lingonberry nectar/fermented lingonberry juice, and phenolic fractions with active molecules are reviewed. Lingonberry's bioactive substances have a diverse range of antimicrobial, anti-inflammatory, antiproteolytic, anticancer, and antioxidant properties. Fermentation of lingonberries and modulation of the dysbiotic microbiome to a more symbiotic composition by favoring the growth of lactobacilli and inhibiting the growth of human opportunistic pathogens are discussed. Research results suggest that more studies on humans are needed.

Lingonberry (Vaccinium vitis-idaea L.) Skin Extract Prevents Weight Gain and Hyperglycemia in High-Fat Diet-Induced Model of Obesity in Mice

The percentage of obese people is increasing worldwide, causing versatile health problems. Obesity is connected to diseases such as diabetes and cardiovascular diseases, which are preceded by a state called metabolic syndrome. Diets rich in fruits and vegetables have been reported to decrease the risk of metabolic syndrome and type 2 diabetes. Berries with a high polyphenol content, including lingonberry (Vaccinium vitis-idaea L.), have also been of interest to possibly prevent obesity-induced metabolic disturbances. In the present study, we prepared an extract from the by-product of a lingonberry juice production process (press cake/pomace) and investigated its metabolic effects in the high-fat diet-induced model of obesity in mice. The lingonberry skin extract partly prevented weight and epididymal fat gain as well as a rise in fasting glucose level in high-fat diet-fed mice. The extract also attenuated high-fat diet-induced glucose intolerance as measured by an intraperitoneal glucose tolerance test (IPGTT). The extract had no effect on the levels of cholesterol, triglyceride or the adipokines adiponectin, leptin, or resistin. The results extend previous data on the beneficial metabolic effects of lingonberry. Further research is needed to explore the mechanisms behind these effects and to develop further health-promoting lingonberry applications.

Polyphenols: immunonutrients tipping the balance of immunometabolism in chronic diseases

Mounting evidence progressively appreciates the vital interplay between immunity and metabolism in a wide array of immunometabolic chronic disorders, both autoimmune and non-autoimmune mediated. The immune system regulates the functioning of cellular metabolism within organs like the brain, pancreas and/or adipose tissue by sensing and adapting to fluctuations in the microenvironment's nutrients, thereby reshaping metabolic pathways that greatly impact a pro- or anti-inflammatory immunophenotype. While it is agreed that the immune system relies on an adequate nutritional status to function properly, we are only just starting to understand how the supply of single or combined nutrients, all of them termed immunonutrients, can steer immune cells towards a less inflamed, tolerogenic immunophenotype. Polyphenols, a class of secondary metabolites abundant in Mediterranean foods, are pharmacologically active natural products with outstanding immunomodulatory actions. Upon binding to a range of receptors highly expressed in immune cells (e.g. AhR, RAR, RLR), they act in immunometabolic pathways through a mitochondria-centered multi-modal approach. First, polyphenols activate nutrient sensing via stress-response pathways, essential for immune responses. Second, they regulate mammalian target of rapamycin (mTOR)/AMP-activated protein kinase (AMPK) balance in immune cells and are well-tolerated caloric restriction mimetics. Third, polyphenols interfere with the assembly of NLR family pyrin domain containing 3 (NLRP3) in endoplasmic reticulum-mitochondria contact sites, inhibiting its activation while improving mitochondrial biogenesis and autophagosome-lysosome fusion. Finally, polyphenols impact chromatin remodeling and coordinates both epigenetic and metabolic reprogramming. This work moves beyond the well-documented antioxidant properties of polyphenols, offering new insights into the multifaceted nature of these compounds. It proposes a mechanistical appraisal on the regulatory pathways through which polyphenols modulate the immune response, thereby alleviating chronic low-grade inflammation. Furthermore, it draws parallels between pharmacological interventions and polyphenol-based immunonutrition in their modes of immunomodulation across a wide spectrum of socioeconomically impactful immunometabolic diseases such as Multiple Sclerosis, Diabetes (type 1 and 2) or even Alzheimer's disease. Lastly, it discusses the existing challenges that thwart the translation of polyphenols-based immunonutritional interventions into long-term clinical studies. Overcoming these limitations will undoubtedly pave the way for improving precision nutrition protocols and provide personalized guidance on tailored polyphenol-based immunonutrition plans.

Anthocyanins as Immunomodulatory Dietary Supplements: A Nutraceutical Perspective and Micro-/Nano-Strategies for Enhanced Bioavailability

Anthocyanins (ACNs) have attracted considerable attention for their potential to modulate the immune system. Research has revealed their antioxidant and anti-inflammatory properties, which play a crucial role in immune regulation by influencing key immune cells, such as lymphocytes, macrophages, and dendritic cells. Moreover, ACNs contribute towards maintaining a balance between proinflammatory and anti-inflammatory cytokines, thus promoting immune health. Beyond their direct effects on immune cells, ACNs significantly impact gut health and the microbiota, essential factors in immune regulation. Emerging evidence suggests that they positively influence the composition of the gut microbiome, enhancing their immunomodulatory effects. Furthermore, these compounds synergize with other bioactive substances, such as vitamins and minerals, further enhancing their potential as immune-supporting dietary supplements. However, detailed clinical studies must fully validate these findings and determine safe dosages across varied populations. Incorporating these natural compounds into functional foods or supplements could revolutionize the management of immune-related conditions. Personalized nutrition and healthcare strategies may be developed to enhance overall well-being and immune resilience by fully understanding the mechanisms underlying the actions of their components. Recent advancements in delivery methods have focused on improving the bioavailability and effectiveness of ACNs, providing promising avenues for future applications.