T cell addiction: can pathogenic T cells be controlled using dopamine receptors?

The Dopamine Gene Receptors (DRD1-5) Expression Alteration in Psoriasis Patients

BACKGROUND

Psoriasis is a chronic inflammatory autoimmune disease that is considered linked to genetic and environmental factors such as stress. Since the neurotransmitter dopamine has a close association with stress configuration, it can be a candidate for relieving psoriasis representation. In addition to the CNS, immune cells can play a decisive role in regulating immune functions through dopamine synthesis and the expression of its receptors. Altered response of immune cells to dopamine as well as a distorted expression of dopamine receptors (DRs) in immune cells have been reported in some chronic inflammatory conditions.

OBJECTIVE

This study aims the evaluation of dopamine receptor (DR1-DR5) gene expression in mononuclear blood cells of psoriatic patients in comparison with normal individuals.

METHODS

We isolated peripheral mononuclear cells (PBMCs) from blood samples followed by total RNA extraction, cDNA synthesis, and real-time PCR using specific primer pairs.

RESULTS

We found that all types of DRs are expressed in the PBMCs of normal and psoriatic individuals. We also concluded that compared to controls, DR2 and DR4 were overexpressed in psoriasis patients while DR3 was low-expressed.

CONCLUSION

Increased expression of DR2 and DR4 along with decreased expression of DR3 in PBMCs of psoriasis patients not only provide new insight into the pathogenesis of psoriasis but may also be effective in designing future therapeutic strategies attributable to psoriasis.

Profiling Blood Serum Extracellular Vesicles in Plaque Psoriasis and Psoriatic Arthritis Patients Reveals Potential Disease Biomarkers

Psoriasis vulgaris (PsV) and psoriatic arthritis (PsA) are inflammatory diseases with unresolved pathophysiological aspects. Extracellular vesicles (EVs) play an important role in intercellular communication. We compared the miRNA contents and surface proteome of the EVs in the blood serum of PsV and PsA patients to healthy controls. Size-exclusion chromatography was used to isolate EVs from the blood serum of 12 PsV patients, 12 PsA patients and 12 healthy control subjects. EV samples were characterized and RNA sequencing was used to identify differentially enriched EV-bound miRNAs. We found 212 differentially enriched EV-bound miRNAs present in both PsV and PsA groups—a total of 13 miRNAs at FDR ≤ 0.05. The predicted target genes of these miRNAs were significantly related to lesser known but potentially disease-relevant pathways. The EV array revealed that PsV patient EV samples were significantly enriched with CD9 EV-marker compared to controls. Analysis of EV-bound miRNAs suggests that signaling via EVs in the blood serum could play a role in the pathophysiological processes of PsV and PsA. EVs may be able to fill the void in clinically applicable diagnostic and prognostic biomarkers for PsV and PsA.

Gut-Brain-Skin Axis in Psoriasis: A Review

Introduction

Psoriasis is a common skin disease, with chronic inflammation and a complex etiology. It has long been recognized that chronic skin conditions and mental health disorders are often co-morbid. Thus, the concept of the gut–brain–skin axis emphasized in mental health disorders may also regulate the health of skin.

Results

The gut microbiota has been found to be the bridge between the immune system and nervous system. By leveraging clinical cases and animal models of psoriasis, an important communication pathway has been identified along the gut–brain–skin axis that is associated with the modulation of neurotransmitters from the microbiota. Furthermore, mammalian neurotransmitters, including dopamine, serotonin, or γ-aminobutyric acid (GABA), can be produced and/or consumed by several types of bacteria. Other studies suggest that manipulating these neurotransmitters by bacteria may have an effect on host physiology, and the levels of neurotransmitter can be altered by microbiota-based interventions.

Conclusions

Nonetheless, it is unknown whether or not the manipulation of neurotransmitter levels by bacteria can affect the occurrence and development of psoriasis. Notably, preliminary experiments found that oral consumption of probiotics improves the clinical symptoms in patients with psoriasis, perhaps correlated with the gut microbiome-mediated crosstalk between the immune system and the nervous system by secreting neurotransmitters in psoriasis. In this review, the communication along the gut–brain–skin axis is discussed.

Intoxication With Endogenous Angiotensin II: A COVID-19 Hypothesis

Severe acute respiratory syndrome coronavirus 2 has spread rapidly around the globe. However, despite its high pathogenicity and transmissibility, the severity of the associated disease, COVID-19, varies widely. While the prognosis is favorable in most patients, critical illness, manifested by respiratory distress, thromboembolism, shock, and multi-organ failure, has been reported in about 5% of cases. Several studies have associated poor COVID-19 outcomes with the exhaustion of natural killer cells and cytotoxic T cells, lymphopenia, and elevated serum levels of D-dimer. In this article, we propose a common pathophysiological denominator for these negative prognostic markers, endogenous, angiotensin II toxicity. We hypothesize that, like in avian influenza, the outlook of COVID-19 is negatively correlated with the intracellular accumulation of angiotensin II promoted by the viral blockade of its degrading enzyme receptors. In this model, upregulated angiotensin II causes premature vascular senescence, leading to dysfunctional coagulation, and immunity. We further hypothesize that angiotensin II blockers and immune checkpoint inhibitors may be salutary for COVID-19 patients with critical illness by reversing both the clotting and immune defects (Graphical Abstract).