Search Results (6)

Hemozoin (Hz) is a heme crystal produced during malaria infection that stimulates immune cells, leading to the production of cytokines and chemokines. The immunostimulatory action of Hz has previously been applied in the development of alternative adjuvants. Crystallization of hemin is a chemical approach for producing Hz. Here, we focused on an enzymatic production method for Hz using the heme detoxification protein (HDP), which catalyzes heme dimer formation from hemin in Plasmodium. We examined the immunostimulatory effects of an enzymatically synthesized analog of Hz (esHz) produced by recombinant Plasmodium falciparum HDP. Enzymatically synthesized Hz stimulates a macrophage cell line and human peripheral mononuclear cells, leading to the production of interleukin (IL)-6 and IL-12p40. In mice, subcutaneous administration of esHz together with an antigen, ovalbumin (OVA), increased the OVA-specific immunoglobulin (Ig) G2c isotype level in the serum, whereas OVA-specific IgG1 was not induced. Our findings suggest that esHz is a useful Th-1 cell adjuvant. Full article

Alzheimer’s disease (AD) represents a pressing global health challenge, with an anticipated surge in diagnoses over the next two decades. This progressive neurodegenerative disorder unfolds gradually, with observable symptoms emerging after two decades of imperceptible brain changes. While traditional therapeutic approaches, such as medication and cognitive therapy, remain standard in AD management, their limitations prompt exploration into novel integrative therapeutic approaches. Recent advancements in AD research focus on entraining gamma waves through innovative methods, such as light flickering and electromagnetic fields (EMF) stimulation. Flickering light stimulation (FLS) at 40 Hz has demonstrated significant reductions in AD pathologies in both mice and humans, providing improved cognitive functioning. Additionally, recent experiments have demonstrated that APOE mutations in mouse models substantially reduce tau pathologies, with microglial modulation playing a crucial role. EMFs have also been demonstrated to modulate microglia. The exploration of EMFs as a therapeutic approach is gaining significance, as many recent studies have showcased their potential to influence microglial responses. Th article concludes by speculating on the future directions of AD research, emphasizing the importance of ongoing efforts in understanding the complexities of AD pathogenesis through a holistic approach and developing interventions that hold promise for improved patient outcomes. Full article

An inadequate stress response is associated with impaired neuroimmunoendocrine communication, increasing morbidity and mortality. Since catecholamines (CA) constitute one of the acute stress response pathways, female mice with an haploinsufficiency of the tyrosine hydroxylase gene (TH-HZ), the main limiting enzyme in CA synthesis, show low CA amounts, exhibiting an impairment of homeostatic systems. The aim of this study was to investigate the effect of a punctual stress in TH-HZ mice, determining the differences with wild-type (WT) mice and those due to sex by restraint with a clamp for 10 min. After restraint, a behavioral battery was performed, and several immune functions, redox state parameters, and CA amounts were evaluated in peritoneal leukocytes. Results show that this punctual stress impaired WT behavior and improved female WT immunity and oxidative stress, whereas in TH-HZ mice, all parameters were impaired. In addition, different responses to stress due to sex were observed, with males having a worse response. In conclusion, this study confirms that a correct CA synthesis is necessary to deal with stress, and that when a positive stress (eustress) occurs, individuals may improve their immune function and oxidative state. Furthermore, it shows that the response to the same stressor is different according to sex. Full article

Herpes zoster (HZ) is caused by the reactivation of latent varicella-zoster virus (VZV) from the sensory ganglia due to aging or immunosuppression. Glycoprotein E (gE) is a widely used vaccine antigen for specific humoral and cellular immune responses. Immediate early protein 63 (IE63) is expressed during latency, suggesting that it is a potential antigen against HZ reactivation. In this study, HZ DNA vaccines encoding gE, IE63, IE63-2A-gE (where 2A is a self-cleaving sequence), or IE63-linker-gE were developed and investigated for immunogenicity in mice. The results showed that each HZ DNA vaccine induced VZV-specific antibody production. The neutralizing antibody titer elicited by IE63-2A-gE was comparable to that elicited by gE or live attenuated HZ vaccine (LAV). IE63-2A-gE-induced gE or IE63-specific INF-γ⁺ T cell frequencies in splenocytes were comparable to those of LAV. Furthermore, IE63-2A-gE, gE, or IE63 led to a significant increase in IFN-γ (IE63 stimulation) and IL-2 (gE stimulation) secretion compared to LAV, showing a Th1-biased immune response. Moreover, IE63-2A-gE and gE induced cytotoxic activity of CD8⁺ T cells compared to that of LAV. This study elucidates that the IE63-2A-gE DNA vaccine can induce both humoral and cell-mediated immune responses, which provides a candidate for the development of an HZ vaccine. Full article

Beta-phenylethylamine (β-PEA) is a well-known and widespread endogenous neuroactive trace amine found throughout the central nervous system in humans. In this study, we demonstrated the effects of β-PEA on psychomotor, rewarding, and reinforcing behaviors and affective state using the open-field test, conditioned place preference (CPP), self-administration, and ultrasonic vocalizations (USVs) paradigms. We also investigated the role of the dopamine (DA) D1 receptor in the behavioral effects of β-PEA in rodents. Using enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting, we also determined the DA concentration and the DA-related protein levels in the dorsal striatum of mice administered with acute β-PEA. The results showed that acute β-PEA increased stereotypic behaviors such as circling and head-twitching responses in mice. In the CPP experiment, β-PEA increased place preference in mice. In the self-administration test, β-PEA significantly enhanced self-administration during a 2 h session under fixed ratio (FR) schedules (FR1 and FR3) and produced a higher breakpoint during a 6 h session under progressive ratio schedules of reinforcement in rats. In addition, acute β-PEA increased 50-kHz USV calls in rats. Furthermore, acute β-PEA administration increased DA concentration and p-DAT and TH expression in the dorsal striatum of mice. Finally, pretreatment with SCH23390, a DA D1 receptor antagonist, attenuated β-PEA-induced circling behavior and β-PEA-taking behavior in rodents. Taken together, these findings suggest that β-PEA has rewarding and reinforcing effects and psychoactive properties, which induce psychomotor behaviors and a positive affective state by activating the DA D1 receptor in the dorsal striatum. Full article

Oxidative and inflammatory stresses are closely related processes, which contribute to age-associated impairments that affect the regulatory systems such as the immune system and its immunosenescence. Therefore, the aim of this work was to confirm whether an oxidative/inflammatory stress occurs in immune cells from adult mice with premature aging, similar to that shown in leukocytes from chronologically old animals, and if this results in immunosenescence. Several oxidants/antioxidants and inflammatory/anti-inflammatory cytokines were analyzed in peritoneal leukocytes from adult female CD1 mice in two models of premature aging—(a) prematurely aging mice (PAM) and (b) mice with the deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase (th) gene (TH-HZ), together with cells from chronologically old animals. Several immune function parameters were also studied in peritoneal phagocytes and lymphocytes. The same oxidants and antioxidants were also analyzed in spleen and thymus leukocytes. The results showed that the immune cells of PAM and TH-HZ mice presented lower values of antioxidant defenses and higher values of oxidants/pro-inflammatory cytokines than cells from corresponding controls, and similar to those in cells from old animals. Moreover, premature immunosenescence in peritoneal leukocytes from both PAM and TH-HZ mice was also observed. In conclusion, adult PAM and TH-HZ mice showed oxidative stress in their immune cells, which would explain their immunosenescence. Full article