Anexelekto (AXL) no more: microRNA-155 (miR-155) controls the "Uncontrolled" in SARS-CoV-2

AXL is the gene that encodes the Anexelekto (AXL) receptor tyrosine kinase that demonstrates significant roles in various cellular processes, including cell growth, survival, and migration. Anexelekto is a Greek word meaning excessive and uncontrolled, semantically implying the crucial involvement of AXL in cancer and immune biology, and in promoting cancer metastasis. AXL overexpression appears to drive epithelial to mesenchymal transition, tumor angiogenesis, decreased antitumor immune response, and resistance to therapeutic agents. Recently, AXL has been reported to play important roles in several viral infections, including SARS-CoV-2. We have previously outlined the importance of microRNAs (miRNAs, miRs) and especially miR-155 in SARS-CoV-2 pathophysiology through regulation of the Renin-Angiotensin Aldosterone System (RAAS) and influence on several aspects of host innate immunity. MiRNAs are negative regulators of gene expression, decreasing the stability of target RNAs or limiting their translation and, enthrallingly, miR-155 is also involved in AXL homeostasis-both endogenously and pharmaceutically using repurposed drugs (e.g., metformin)-highlighting thrifty evolutionary host innate immunity mechanisms that successfully can thwart viral entry and replication. Cancer, infections, and immune system disturbances will increasingly involve miRNA diagnostics and therapeutics in the future.

Live to die another day: novel insights may explain the pathophysiology behind smoker's paradox in SARS-CoV-2 infection

The severe acute respiratory coronavirus 2 (SARS-CoV-2) infection demonstrates a highly variable and unpredictable course. Several reports have claimed a smoker's paradox in coronavirus disease 2019 (COVID-19), in line with previous suggestions that smoking is associated with better survival after acute myocardial infarction and appears protective in preeclampsia. Several plausible physiological explanations exist accounting for the paradoxical observation of smoking engendering protection against SARS-CoV-2 infection. In this review, we delineate novel mechanisms whereby smoking habits and smokers' genetic polymorphism status affecting various nitric oxide (NO) pathways (endothelial NO synthase, cytochrome P450 (CYP450), erythropoietin receptor (EPOR); β-common receptor (βcR)), along with tobacco smoke modulation of microRNA-155 and aryl-hydrocarbon receptor (AHR) effects, may be important determinators of SARS-CoV-2 infection and COVID-19 course. While transient NO bioavailability increase and beneficial immunoregulatory modulations through the above-mentioned pathways using exogenous, endogenous, genetic and/or therapeutic modalities may have direct and specific, viricidal SARS-CoV-2 effects, employing tobacco smoke inhalation to achieve protection equals self-harm. Tobacco smoking remains the leading cause of death, illness, and impoverishment.

Beauty and the beast: host microRNA-155 versus SARS-CoV-2

Severe acute respiratory coronavirus 2 (SARS-CoV-2) infection in the young and healthy usually results in an asymptomatic or mild viral syndrome, possibly through an erythropoietin (EPO)-dependent, protective evolutionary landscape. In the old and in the presence of co-morbidities, however, a potentially lethal coronavirus disease 2019 (COVID-19) cytokine storm, through unrestrained renin-angiotensin aldosterone system (RAAS) hyperactivity, has been described. Multifunctional microRNA-155 (miR-155) elevation in malaria, dengue virus (DENV), the thalassemias, and SARS-CoV-1/2, plays critical antiviral and cardiovascular roles through its targeted translational repression of over 140 genes. In the present review, we propose a plausible miR-155-dependent mechanism whereby the translational repression of AGRT1, Arginase-2 and Ets-1, reshapes RAAS towards Angiotensin II (Ang II) type 2 (AT2R)-mediated balanced, tolerable, and SARS-CoV-2-protective cardiovascular phenotypes. In addition, it enhances EPO secretion and endothelial nitric oxide synthase activation and substrate availability, and negates proinflammatory Ang II effects. Disrupted miR-155 repression of AT1R + 1166C-allele, significantly associated with adverse cardiovascular and COVID-19 outcomes, manifests its decisive role in RAAS modulation. BACH1 and SOCS1 repression creates an anti-inflammatory and cytoprotective milieu, robustly inducing antiviral interferons. MiR-155 dysregulation in the elderly, and in comorbidities, allows unimpeded RAAS hyperactivity to progress towards a particularly aggressive COVID-19 course. Elevated miR-155 in thalassemia plausibly engenders a favorable cardiovascular profile and protection against malaria, DENV, and SARS-CoV-2. MiR-155 modulating pharmaceutical approaches could offer novel therapeutic options in COVID-19.

Assessment of chondrogenic differentiation potential of autologous activated peripheral blood stem cells on human early osteoarthritic cancellous tibial bone scaffold

INTRODUCTION

Current therapeutic regimens in osteoarthritis (OA) address mainly pain but not the slow progressive degradation of the extracellular matrix (ECM) and the loss of a chondrogenic phenotype in articular cartilage. In the present study, using an early OA cancellous bone scaffold, we aimed to uncover evidence of the successful hyaline cartilage regenerative capacity of autologous human granulocyte colony-stimulating factor (hG-CSF)-activated peripheral blood stem cells (AAPBSC) with growth factor addition.

MATERIALS AND METHODS

AAPBSC were harvested in ten patients (median age 58 years, 8 females), and flow cytometry was performed for cell surface markers. Arthroscopically obtained cancellous bone scaffold specimens were seeded with AAPBSC. In Group 1, the scaffold was seeded with AAPBSC only, in Group 2, AAPBSC plus hyaluronic acid (HA), and in Group 3, AAPBSC plus HA, hG-CSF, and double-centrifuged platelet-rich plasma (PRP). The specimens were analyzed for cell attachment and proliferation by the fluorometric quantification of cellular DNA assay and scanning electron microscopy. Chondrogenic gene expression was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) of Sox9, collagen type II (COL-2), and aggrecan. Histological sections of scaffold constructs for cartilaginous matrix formation were stained with toluidine blue (proteoglycan) and safranin O (sGAG) after 3 weeks.

RESULTS

AAPBSC displayed especially high levels of CD29 and CD44 surface markers, as well as CD90, and CD105, while only a small proportion expressed CD34. Almost half of the seeded cells attached on the bone scaffolds in all three groups (not statistically significant), whereas the means of cell proliferation on day 7 compared to day 1 were statistically significant difference with the order of increase as group 3 > group 2 > group 1. RT-PCR showed statistically significant sequential increases in Sox9, COL-2, and Aggrecan all being highest in group 3. Histological analysis demonstrated cells in the cancellous bone scaffold with a round morphology, and ECM was positively stained by toluidine blue and safranin O indicating increased proteoglycan and glycosaminoglycan content, respectively, in the newly formed cartilage matrix.

CONCLUSIONS

AAPBSC initiated chondrocyte differentiation on an autologous cancellous bone scaffold, and the addition of PRP and hG-CSF further stimulated cell proliferation toward a chondrocyte phenotype with potentiated Sox9 transcription resulting in sequential COL-2 and aggrecan mRNA increases that ultimately resulted in histologically confirmed increased proteoglycan and glucosaminoglycan content in newly formed hyaline cartilage.

Angiotensin converting enzyme (ACE) gene polymorphism in sarcoidosis in relation to associated autoimmune diseases

OBJECTIVES

To investigate the significance of ACE gene insertion/deletion (I/D) polymorphism in the frequency of autoimmune manifestations in sarcoidosis.

DESIGN

In patients with sarcoidosis the ACE gene I/D polymorphism was detected with PCR on genomic DNA. The patients with sarcoidosis were divided according to the presence (n = 30) or absence (n = 32) of autoimmune manifestations. The former group was subdivided into thyroid autoimmunity (n = 10), gluten immune reactivity (n = 10) and gastric autoimmunity (n = 17).

SETTINGS

The patients were recruited at the Department of Pulmonary Medicine, and the study was conducted at the Department of Endocrinology, University of Lund, Malmö University Hospital, Malmö, Sweden.

SUBJECTS

Sixty-two patients with documented sarcoidosis (30 females, 32 males, median age/range at diagnosis of sarcoidosis 31.5/19-75 years, median age/range at study 47.5/22-81 years) were examined. A total of 107 healthy unrelated subjects without sarcoidosis (60 females, 47 males, median age/range at study 58/40-82 years) served as controls.

RESULTS

S-ACE values were significantly increased in patients compared to controls (P = 0.00001). The same was true in the subgroup of sarcoidosis patients with associated autoimmunity compared with those with isolated sarcoidosis (P = 0.0328). A significant association was seen between ACE gene polymorphism (II, ID, DD genotypes) and S-ACE levels in both patients and controls according to the order II < ID < DD. The observed genotype frequency distributions in the different study groups agreed the Hardy-Weinberg equilibrium without significant differences between the patients and the controls. Within the group with autoimmune manifestations the DD genotype was significantly over-represented in X-ray stage III compared to the other X-ray stages (P = 0.0181) and a significant increase in the DD genotype in X-ray stage III (P = 0.035) in the group with autoimmune manifestations compared to isolated sarcoidosis was detected.

CONCLUSION

We confirmed that the S-ACE levels corresponded to the order II < ID < DD in patients with sarcoidosis as well as in healthy controls. S-ACE levels were significantly higher in sarcoidosis patients with autoimmune manifestations. The frequency of the DD genotype was significantly increased in patients with autoimmune manifestations and major granuloma mass (X-ray stage III). The ACE D allele in its homozygous form may confer susceptibility for autoimmune manifestations in sarcoidosis, possibly via the high levels of S-ACE it encodes.

Evidence of gastrointestinal immune reactivity in patients with sarcoidosis

OBJECTIVES

The aim of the present study was to explore the frequency of clinical and serological manifestations of gastrointestinal immune reactivity in a large group of Swedish patients with sarcoidosis.

DESIGN

In patients with documented sarcoidosis, the presence of pernicious anaemia and coeliac disease was examined. Antibodies to H+/K+ ATPase, gliadin (AGA-IgA/IgG) and endomysium (IgA-EMA) were analysed. In H+/K+ ATPase antibody-positive patients, serum gastrin levels were measured and, when elevated, gastrointestinal biopsy was offered (biopsy performed in 6/9 patients): biopsy was also offered to those with positive EMA or AGA of either class (biopsy performed in 8/12 patients). Subjects from national and local studies were used as controls.

SETTING

The patients were recruited at the Department of Pulmonary Medicine, and the study was conducted at the Department of Endocrinology, University of Lund, Malmö University Hospital, Malmö, Sweden.

SUBJECTS

Of all patients (n = 89) with documented sarcoidosis attending the Department of Pulmonary Medicine between January 1980 and December 1991, 78 [34 females and 44 males; median age at the time of the study, 48 (range 22-81) years; median observation time since the diagnosis of sarcoidosis, 120 (range 1-468) months] were examined.

RESULTS

Twenty-nine patients (37.2%) had signs of gastrointestinal immune reactivity. H+/K+ ATPase antibodies were detected in 19 patients (24.4 vs. 4% in controls, P = 0.00015). Serum gastrin levels (median 45, range 22-720 pmol L(-1)) in those patients correlated with antibody titre (r2 = 0.882). Gliadin antibodies were detected in 12 patients (15.4 vs. 8.1% in controls, P = 0.042), of whom 11 (14.1 vs. 4.5% in controls, P = 0.00114) had AGA-IgA alone. One patient had pernicious anaemia and another coeliac disease (EMA-positive).

CONCLUSION

We have demonstrated a high frequency of gastric autoimmunity and gluten-associated immune reactivity in patients with sarcoidosis, occurring in almost 40% of the cases, the former being the most frequent gastrointestinal immune manifestation. Despite a high frequency of humoral autoimmunity, the frequencies of clinical disease, pernicious anaemia and coeliac disease were not increased as compared with the control population.

Thyrotoxic period paralysis: report of three cases and review of the literature

Thyrotoxic periodic paralysis (TPP) is a neuromuscular disorder that, in a global perspective, only affects a small percentage of patients with thyrotoxicosis of any aetiology, but is a fairly common phenomenon in Asian populations where it predominantly occurs in males. Three typical cases are presented here. All three patients were Asian males, one being the first Laotian patient reported to have this disorder. In one case prodromal symptoms of TPP occurred during a relapse of the thyrotoxicosis. The epidemiology, clinical manifestations, aetiology and treatment of this relatively rare condition are discussed. As oriental races are now frequently encountered in the Western world, it is imperative that TPP is included in the differential diagnosis of muscle weakness in order to avoid the life-threatening complications of hypokalaemia and thyrotoxicosis.

High frequency of endocrine autoimmunity in patients with sarcoidosis

Autoimmune diseases and sarcoidosis may be related and, especially, the association between sarcoidosis and autoimmune thyroid disease has long been recognized. The frequency and type of endocrine autoimmunity was examined in a series of Swedish patients with sarcoidosis. Of all patients (N = 89) with documented sarcoidosis attending the Department of Pulmonary Medicine between January 1980 and December 1991, 78 patients (44 males and 34 females; median age at the time of the study 48 years. range 22-81 years) were examined at the Department of Endocrinology, Malmö University Hospital, in the present study. Fifteen patients (19.2%) had clinical or serological evidence of endocrine autoimmunity. Two patients had Addison's disease, both with polyglandular autoimmune (PGA) syndrome type II: evidence of thyroid autoimmunity was found in 13 patients, eight with clinical autoimmune thyroid disease (ATD) (two with Graves' disease and six with autoimmune thyroiditis), of whom two had PGA syndrome type III, and five with isolated positive thyroid serology; two patients had insulin-dependent diabetes mellitus and one had premature ovarian failure. The frequencies of Addison's disease, clinical ATD and PGA syndrome type II were significantly higher compared with the frequencies found in the general population. In conclusion, a high frequency of endocrine autoimmunity in patients with sarcoidosis, occurring in about 20% of the cases, was demonstrated. Thyroid autoimmunity and polyglandular autoimmune syndromes occurred most frequently. Complex immunological and genetic mechanisms might explain the association of sarcoidosis and endocrine autoimmune diseases.

Bilateral isolated adrenal coccidioidomycosis

A case of bilateral isolated adrenal coccidioidomycosis in a previously healthy and immunocompetent 43-year-old Caucasian male is presented. He had never travelled to a coccidioidomycosis endemic area. Subclinical adrenal dysfunction was found with elevated plasma ACTH and mineralocorticosteroid and androgen pathway abnormalities. The implement of the fungal infection on adrenal function, and the diagnosis and management of adrenal coccidioidomycosis are discussed.

Islet cell and glutamic acid decarboxylase antibodies in hyperthyroid patients: at diagnosis and following treatment

OBJECTIVES

To study the frequency of islet cell (ICA) and glutamic acid decarboxylase (GAD-Ab) antibodies in patients with hyperthyroidism of different types at diagnosis before treatment and in the euthyroid state following treatment.

SETTING

Department of Endocrinology, Malmö University Hospital, Malmö, Sweden.

SUBJECTS AND DESIGN

Blood samples were collected at diagnosis from 129 hyperthyroid patients, and about 6 months later, from 78 of the patients (euthyroid state). Ninety-two patients had Graves' disease (69 females and 23 males, median age 49 years, range 17-85 years), and 37 patients had toxic nodular goitre/solitary toxic adenoma (34 females and three males, median age 69 years, range 24-86 years).

INTERVENTIONS

Most patients were treated by radioactive iodine following the first blood sample.

MAIN OUTCOME MEASURES

ICA and GAD-Ab in serum.

RESULTS

At diagnosis of Graves' disease, ICA were detected in two out of 92 (2.2%) patients, two out of 85 (2.4%) without diabetes mellitus and in the euthyroid state in one patient. None of the patients with toxic nodular goitre/solitary toxic adenoma had detectable ICA. At diagnosis of Graves' disease, GAD65-Ab as well as GAD67-Ab were detected in 11 out of 85 (13%) patients without diabetes. As many as six out of 11 GAD67-Ab-positive patients were GAD65-Ab negative. In the euthyroid state, GAD65-Ab were found in six out of 51 (12%) and GAD67-Ab in eight out of 51 (16%) of the non-diabetic Graves' disease patients. The frequencies of GAD65-Ab and GAD67-Ab in toxic nodular goitre/solitary toxic adenoma, diabetes excluded, were 3 and 0%, respectively, in the hyperthyroid state.

CONCLUSION

The frequency of ICA in patients with hyperthyroidism is not increased as compared to the background population. GAD-Ab seems to be associated with Graves' disease and not with hyperthyroidism. The presence of GAD67-Ab in GAD65-Ab negative sera from patients with Graves' disease indicates autoreactivity against a specific GAD67 epitope.

Primary antiphospholipid syndrome associated with postoperative primary adrenal failure

A 51-year-old Caucasian male without previous history of thromboembolic disease developed Coomb's positive haemolytic anaemia, thrombocytopenia, transient paranoid psychosis and bilateral adrenal haemorrhage with primary adrenal failure after surgery for inguinal hernia. The activated partial thromboplastin time was spontaneously prolonged, and lupus anticoagulant and anticardiolipin antibodies were detected. In the absence of criteria for classification of systemic lupus erythematosus (SLE), the entity was classified as a primary antiphospholipid syndrome. Despite the persistence of the serological abnormalities, the patient remains well after substitution with cortisone. Primary adrenal failure due to adrenal haemorrhage can be associated with the primary antiphospholipid syndrome.

The occurrence of polyglandular autoimmune syndrome type III associated with coeliac disease in patients with sarcoidosis

OBJECTIVES

To study whether an association between polyglandular autoimmune (PGA) syndrome type III [including autoimmune thyroid disease (ATD) and insulin-dependent diabetes mellitus (IDDM)], coeliac disease and sarcoidosis, exists.

DESIGN

In patients with documented sarcoidosis, the presence of the disease constellation of ATD, IDDM and coeliac disease was examined.

SETTING

The patients were recruited at the Department of Pulmonary Medicine, and the study was conducted at the Department of Endocrinology, Lund University Clinics, General Hospital, Malmö, Sweden.

SUBJECTS

Of all patients (n = 89) with documented sarcoidosis attending the Department of Pulmonary Medicine between January 1980 and December 1991, 78 patients (44 males, 34 females: median age at the time of the study 48 years, range 22-81 years: median observation time since the diagnosis of sarcoidosis 120 months, range 1-468 months) were examined in the present study.

RESULTS

Amongst the 78 patients with documented sarcoidosis, one female patient was found with PGA syndrome type III, coeliac disease and sarcoidosis.

CONCLUSIONS

This present patient further indicates the existence of an association between polyglandular autoimmune (PGA) syndrome type III, coeliac disease and sarcoidosis. To determine whether this disease constellation might constitute a new syndrome, further studies on larger groups of patients with sarcoidosis are demanded.

Polyglandular autoimmune syndrome type III associated with coeliac disease and sarcoidosis

A female patient demonstrating a previously not reported constellation of polyglandular autoimmune syndrome type III (including autoimmune thyroiditis, Graves' ophthalmopathy, insulin-dependent diabetes mellitus and vitiligo), coeliac disease and sarcoidosis is described. This may be a random association but might also indicate a common immunological and/or genetic disturbance.

Polyglandular autoimmune syndrome type II in patients with idiopathic Addison's disease

The frequency of polyglandular autoimmune syndrome Type II, (idiopathic or autoimmune Addison's disease associated with autoimmune thyroid disease, and/or insulin-dependent diabetes mellitus), was retrospectively investigated in 44 patients (26 females and 18 males) with idiopathic Addison's disease (median age at onset 32.5 years, range 8-62; median observation time 17 years, range 0.5-41) evaluated between 1966 and 1988 in the Department of Endocrinology, General Hospital, Malmö. Twenty-two patients (16 females and 6 males) fulfilled the criteria for polyglandular autoimmune syndrome Type II and of these 16 had autoimmune thyroid disease and 9 insulin-dependent diabetes mellitus. In 7 of 9 patients insulin-dependent diabetes mellitus developed prior to Addison's disease, whereas autoimmune thyroid disease was diagnosed before as well as after Addison's disease and with a similar age distribution as Addison's disease. In conclusion, the present study indicates that polyglandular autoimmune syndrome Type II occurs in about 50% of patients with idiopathic Addison's disease and that autoimmune thyroid disease is more common than insulin-dependent diabetes mellitus in these patients. The present study also indicates that insulin-dependent diabetes mellitus precedes Addison's disease in a majority of these patients and usually develops at a young age, whereas autoimmune thyroid disease precedes as well as succeeds Addison's disease and occurs at all ages in these patients.