Potential roles of inflammasomes in the pathophysiology of Psoriasis: A comprehensive review

Psoriasis is an inflammatory skin disease whose pathophysiology is attributed to both innate and adaptive immune cells and molecules. Despite the crucial roles of the immune system in psoriasis, it cannot be categorized as an autoimmune disease because of the lack of main signs of autoimmunity, such as specific antibodies, well-defined antigens, and autoimmune genetic risk factors. The presence of some cellular and molecular properties, such as the presence of neutrophils in skin lesions and the activation of the innate immune system, attributes psoriasis to a group of diseases called autoinflammatory disorders. Autoinflammatory diseases refer to a group of inherited disorders whose main manifestations are recurrent fever, a high level of acute-phase reactant, and a tendency for inflammation of the skin, joints, and other organs like the nervous system. In most autoinflammatory disorders, it has been seen that complexes of the high-molecular-weight protein named inflammasomes have significant roles. The inflammasome complex usually is formed and activated in the stimulated immune cell cytoplasm, and its activation consequently leads to inflammatory events such as producing of active caspase-1, mature interleukin-1β (IL-1β), and IL-18 and can cause an inflammatory programmed cell death called pyroptosis. Since the identification of inflammasomes, it has been shown that there are close links between them and hereditary and acquired autoinflammatory diseases like psoriasis. In this review, we aim to focus on well-defined inflammasome and their role in the pathophysiology of psoriasis.

The potential roles of Th17 cells in the pathogenesis of oral lichen planus

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated chronic autoimmune disease, whose pathogenesis and etiology are not entirely understood. OLP is characterized by subepithelial lymphocyte infiltration and elevated intra-epithelial lymphocytes. The majority of lamina propria lymphocytes are CD4⁺ T cells. CD4⁺ helper T (Th) cells play a crucial role in activating CD8⁺ cytotoxic T cells (CTLs) through interactions and cytokine production. Th1 and Th2 cells are well-accepted to be associated with OLP pathogenesis. However, OLP treatment is challenging yet, the more information we have about the pathology of OLP, the easier it will be treated. With the discovery of Th17 cells in recent years and the demonstration of their role in autoimmune disease, many researchers started to investigate the role of Th17 in the pathogenesis of OLP.

METHODS

To make up this review, studies covering the role of TH17 in different types of lichen planus were selected from major databases.

RESULTS

As we review in this article, Th17 cells and their signature cytokines play an important role in OLP pathogenesis. As well, utilizing some anti-IL-17 antibodies showed promising results in improving the disease; however, more studies are still needed to better understand and treat OLP.

Potential roles of NLRP3 inflammasome in the pathogenesis of Kawasaki disease

There is a heterogeneous group of rare illnesses that fall into the vasculitis category and are characterized mostly by blood vessel inflammation. Ischemia and disrupted blood flow will cause harm to the organs whose blood arteries become inflamed. Kawasaki disease (KD) is the most prevalent kind of vasculitis in children aged 5 years or younger. Because KD's cardiovascular problems might persist into adulthood, it is no longer thought of as a self-limiting disease. KD is a systemic vasculitis with unknown initiating factors. Numerous factors, such as genetic predisposition and infectious pathogens, are implicated in the etiology of KD. As endothelial cell damage and inflammation can lead to coronary endothelial dysfunction in KD, some studies hypothesized the crucial role of pyroptosis in the pathogenesis of KD. Additionally, pyroptosis-related proteins like caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC), proinflammatory cytokines like IL-1 and IL-18, lactic dehydrogenase, and Gasdermin D (GSDMD) have been found to be overexpressed in KD patients when compared to healthy controls. These occurrences may point to an involvement of inflammasomes and pyroptotic cell death in the etiology of KD and suggest potential treatment targets. Based on these shreds of evidence, in this review, we aim to focus on one of the well-defined inflammasomes, NLRP3, and its role in the pathophysiology of KD.

Individual genetic variability mainly of Proinflammatory cytokines, cytokine receptors, and toll-like receptors dictates pathophysiology of COVID-19 disease

Innate and acquired immunity responses are crucial for viral infection elimination. However, genetic variations in coding genes may exacerbate the inflammation or initiate devastating cytokine storms which poses severe respiratory conditions in coronavirus disease-19 (COVID-19). Host genetic variations in particular those related to the immune responses determine the patients' susceptibility and COVID-19 severity and pathophysiology. Gene polymorphisms such as single nucleotide polymorphisms (SNPs) of interferons, TNF, IL1, IL4, IL6, IL7, IL10, and IL17 predispose patients to the severe form of COVID-19 or severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). These variations mainly alter the gene expression and cause a severe response by B cells, T cells, monocytes, neutrophils, and natural killer cells participating in a cytokine storm. Moreover, cytokines and chemokines SNPs are associated with the severity of COVID-19 and clinical outcomes depending on the corresponding effect. Additionally, genetic variations in genes encoding toll-like receptors (TLRs) mainly TLR3, TLR7, and TLR9 have been related to the COVID-19 severe respiratory symptoms. The specific relation of these mutations with the novel variants of concern (VOCs) infection remains to be elucidated. Genetic variations mainly within genes encoding proinflammatory cytokines, cytokine receptors, and TLRs predispose patients to COVID-19 disease severity. Understanding host immune gene variations associated with the SARS-COV-2 infection opens insights to control the pathophysiology of emerging viral infections.

A randomized pilot trial on the effect of granulocyte-colony stimulating factor on antibody response in hemodialysis patients who had not responded to routine hepatitis B virus vaccine

Background: Various strategies have been applied to improve the response to hepatitis B virus (HBV) vaccination in hemodialysis patients.

Objectives: The present study was under taken to compare the seroconversion rate of hemodialysis patients who had not respond to 3 intramuscular (IM) doses (40 μg each) of HBV vaccine , after a fourth IM dose (40 μg) of HBV vaccine that was administered alone or with subcutaneous granulocyte-colony stimulating factor (G-CSF) (5 μg/kg).

Patients and Methods: Twenty six hemodialysis patients who had not responded to 3 IM injections of HBV vaccine were randomized into 2 groups: Group 1 received a booster dose of 40 μg HBV vaccine IM, group 2 received a booster dose of 40 μg HBV vaccine IM plus 5 μg/kg subcutaneous G-CSF. Antibody to hepatitis B surface antigen was measured 1 month after the booster dose.

Results: Seroconversion rate in group 1 was 40%. There was a trend towards a higher seroconversion rate at 60% in group 2 patients; however, because of the small number of patients it did not reach statistical significance.

Conclusions: Larger number of patients and other innovative strategies should be applied for vaccination of this group of patients. More prolonged follow up of the patients is needed to evaluate the duration of protection induced by each method of vaccination.

Tibial cortical lesions: a multimodality pictorial review

Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department.

Effect of Silicon Nutrition on Oxidative Stress Induced by Phytophthora melonis Infection in Cucumber

The effect of silicon nutrition on root rot of cucumber caused by Phytophthora melonis was studied in a greenhouse experiment. Two cucumber cultivars (Cucumis sativus 'Dominus' and 'Super Dominus') fertilized with three concentrations of Si (0.0, 1.0, and 1.7 mM Si in the form of sodium silicate) were not inoculated or were inoculated with P. melonis. The P. melonis isolate significantly decreased root dry weights, although the magnitude of growth reduction varied with cultivar and Si concentration. Silicon nutrition at either concentration significantly reduced disease severity relative to the treatment that received no silicon. There was a significant negative correlation between the extent of root rot caused by P. melonis and the extent of electrolyte leakage of roots. Roots infected with P. melonis had greater root catalase (CAT) and ascorbate peroxidase (APX) activities. There was a positive correlation between silicon concentrations and CAT and APX activities in plants inoculated with P. melonis. Silicon improved activity of antioxidant enzymes, resulting in enhanced crop resistance to oxidative stress induced by P. melonis infection and improved cucumber growth.

A case of familial third ventricular colloid cyst

Colloid cyst of the third ventricle is a rare benign intracranial lesion, and familial cases are rarer still. They may be asymptomatic or present with symptoms of raised intracranial pressure, including sudden death. Surgical excision is curative. We report a 24 year old pregnant woman with familial colloid cyst, who presented with headaches and suffered a cardiorespiratory arrest. Early computed tomography scan of the brain is advised in patients with a family history of third ventricular colloid cyst presenting to the accident and emergency department with headache.

Role of the Bloom's syndrome helicase in maintenance of genome stability

The RecQ family of DNA helicases has members in all organisms analysed. In humans, defects in three family members are associated with disease conditions: BLM is defective in Bloom's syndrome, WRN in Werner's syndrome and RTS in Rothmund-Thomson syndrome. In each case, cells from affected individuals show inherent genomic instability. The focus of our work is the Bloom's syndrome gene and its product, BLM. Here, we review the latest information concerning the roles of BLM in the maintenance of genome integrity.

The Bloom's and Werner's syndrome proteins are DNA structure-specific helicases

BLM and WRN, the products of the Bloom's and Werner's syndrome genes, are members of the RecQ family of DNA helicases. Although both have been shown previously to unwind simple, partial duplex DNA substrates with 3'-->5' polarity, little is known about the structural features of DNA that determine the substrate specificities of these enzymes. We have compared the substrate specificities of the BLM and WRN proteins using a variety of partial duplex DNA molecules, which are based upon a common core nucleotide sequence. We show that neither BLM nor WRN is capable of unwinding duplex DNA from a blunt-ended terminus or from an internal nick. However, both enzymes efficiently unwind the same blunt-ended duplex containing a centrally located 12 nt single-stranded 'bubble', as well as a synthetic X-structure (a model for the Holliday junction recombination intermediate) in which each 'arm' of the 4-way junction is blunt-ended. Surprisingly, a 3'-tailed duplex, a standard substrate for 3'-->5' helicases, is unwound much less efficiently by BLM and WRN than are the bubble and X-structure substrates. These data show conclusively that a single-stranded 3'-tail is not a structural requirement for unwinding of standard B-form DNA by these helicases. BLM and WRN also both unwind a variety of different forms of G-quadruplex DNA, a structure that can form at guanine-rich sequences present at several genomic loci. Our data indicate that BLM and WRN are atypical helicases that are highly DNA structure specific and have similar substrate specificities. We interpret these data in the light of the genomic instability and hyper-recombination characteristics of cells from individuals with Bloom's or Werner's syndrome.

DNA helicase deficiencies associated with cancer predisposition and premature ageing disorders

Deficiency in a helicase of the RecQ family is found in at least three human genetic disorders associated with cancer predisposition and/or premature ageing. The RecQ helicases encoded by the BLM, WRN and RECQ4 genes are defective in Bloom's, Werner's and Rothmund-Thomson syndromes, respectively. Cells derived from individuals with these disorders in each case show inherent genomic instability. Recent studies have demonstrated direct interactions between these RecQ helicases and human nuclear proteins required for several aspects of chromosome maintenance, including p53, BRCA1, topoisomerase III, replication protein A and DNA polymerase delta. Here, we review this network of protein interactions, and the clues that they present regarding the potential roles of RecQ family members in DNA repair, replication and/or recombination pathways.

Reducing transmitter release from nerve terminals influences motoneuron survival in developing rats

Motoneurons in neonatal rats die following injury to the peripheral nerve. However, this vulnerability to nerve injury declines rapidly so that nerve injury at five days of age results in little if any motoneuron death. We have proposed that the role of the target during this critical period of development is to up-regulate the release of transmitter from developing motor nerve terminals. Here we show that reducing the release of acetylcholine from nerve terminals in neonatal rats can affect motoneuron maturation and survival. The soleus muscle in neonatal rats was treated with either magnesium or hemicholinium, and the number of motoneurons that survived was established 10 weeks later by retrograde labelling. Following treatment with magnesium, only 58.1% (+/-10.4 S.E.M., n=5) of the motoneurons in the soleus motor pool survived, although hemicholinium had no effect on motoneuron survival. However, those motoneurons that survived following treatment with either magnesium or hemicholinium did not develop normally since they remained susceptible to axotomy-induced cell death for longer than normal. In adult animals in which the sciatic nerve was crushed at five days of age following prior treatment with either magnesium or hemicholinium, only 27.6% (+/-6.2 S.E.M., n=5) and 44% (+/-6.1 S.E.M., n=4) of motoneurons in the sciatic motor pool survived, respectively, although no motoneurons died following injury alone or when injury was preceded by treatment with control implants containing NaCl. These results indicate that the release of acetylcholine from motor nerve terminals plays an important role in the development and survival of motoneurons.

Direct interaction of Smn with dp103, a putative RNA helicase: a role for Smn in transcription regulation?

Spinal muscular atrophy is an autosomal recessive neurodegenerative disease of childhood, resulting from deletion or mutation of the survival motor neuron ( SMN ) gene on chromosome 5q13. SMN exists as part of a 300 kDa multi-protein complex, incorporating several proteins critically required in pre-mRNA splicing. Although SMN mutations render SMN defective in this role, the specific alpha-motor neuron degenerative phenotype seen in the disease remains unexplained. Here we demonstrate the isolation from mouse brain of the murine homologue of a recently identified novel RNA helicase of the DEAD box family, DP103, and its direct and specific binding of SMN. Previous work has shown that DP103 binds viral proteins known to interact with a cellular transcription factor to modulate gene expression. We suggest that the interaction between SMN and DP103 is further evidence for a role for SMN in transcriptional regulation and that SMN may be involved in the regulation of neuron-specific genes essential in neuronal development.

Analysis of mutations in the tudor domain of the survival motor neuron protein SMN

Autosomal recessive childhood onset spinal muscular atrophy (SMA) is a leading cause of infant mortality caused by mutations in the survival motor neuron (SMN) gene. The SMN protein is involved in RNA processing and is localised in structures called GEMs in the nucleus. Nothing is yet understood about why mutations in SMN gene result in the selective motor neuron loss observed in patients. The SMN protein domains conserved across several species may indicate functionally significant regions. Exon 3 of SMN contains homology to a tudor domain, where a Type I SMA patient has been reported to harbour a missense mutation. We have generated missense mutants in this region of SMN and have tested their ability to form GEMs when transfected into HeLa cells. Our results show such mutant SMN proteins still localise to GEMs. Furthermore, exon 7 deleted SMN protein appears to exert a dominant negative effect on localisation of endogenous SMN protein. However, exon 3 mutant protein and exon 5 deleted protein exert no such effect.

Characterization of a gene encoding survival motor neuron (SMN)-related protein, a constituent of the spliceosome complex

Mutations in the gene encoding the Survival Motor Neuron (SMN) protein are responsible for autosomal recessive proximal spinal muscular atrophy (SMA). SMN orthologues have been identified in the nematode worm Caenorhabditis elegans and the yeast Schizosaccharomyces pombe but, to date, no human paralogues have been described. Here we describe identification and characterization of an SMN-related protein (SMNrp) gene that encodes a novel protein of 239 amino acids, which has recently been identified as a constituent of the spliceosome complex and designated SPF30. Significant similarity to the SMN protein is apparent only within a central region of SMNrp that represents a tudor domain. The SMNrp/SPF30 gene has been mapped to chromosome 10q23. It is differentially expressed, with abundant levels in skeletal muscle. An exclusively nuclear localization for SMNrp in cultured cells and muscle sections was revealed using GFP fusion constructs and thereafter confirmed with a polyclonal antibody raised against SMNrp. Overexpression of SMNrp as a fusion protein in HeLa cells in culture induced dose-dependent apoptosis with positive TUNEL staining. In addition to a possible role for this protein as a pro-apoptotic factor, SMN and its related protein share significant similarities in sequence and cellular function.