Depressed activation of the lectin pathway of complement in hereditary angioedema

Inputs for optimizing selection platform for milk production traits of dairy Sahiwal cattle

The premises for the potential success of molecular breeding is the ability to identify major genes associated with important dairy related traits. The present study was taken up with the objectives to identify single nucleotide polymorphism (SNP) of bovine MASP2 and SIRT1 genes and its effect on estimated breeding values (EBVs) and to estimate genetic parameters for lactation milk yield (LMY), 305-day milk yield (305dMY), 305-day fat yield (305dFY), 305-day solid not fat yield (305dSNFY) and lactation length (LL) in Sahiwal dairy cattle to devise a promising improvement strategy. Genetic parameters and breeding values of milk production traits were estimated from 935 Sahiwal cattle population (1979–2019) reared at National Dairy Research Institute at Karnal, India. A total of 7 SNPs, where one SNP (g.499C>T) in exon 2 and four SNPs (g.576G>A, g.609T>C, g.684G>T and g.845A>G) in exon 3 region of MASP2 gene and 2 SNPs (g.-306T>C and g.-274G>C) in the promoter region of SIRT1 gene were identified in Sahiwal cattle population. Five of these identified SNPs were chosen for further genotyping by PCR-RFLP and association analysis. Association analysis was performed using estimated breeding values (n = 150) to test the effect of SNPs on LMY, 305dMY, 305dFY, 305dSNFY and LL. Association analysis revealed that, three SNP markers (g.499C>T, g.609T>C and g.-306T>C) were significantly associated with all milk yield traits. The estimates for heritability using repeatability model for LMY, 305dMY, 305dFY, 305dSNFY and LL were low, however the corresponding estimates from first parity were 0.20±0.08, 0.17±0.08, 0.13±0.09, 0.13±0.09 and 0.24, respectively. The repeatability estimates were moderate to high indicating consistency of performance over the parities and hence reliability of first lactation traits. Genetic correlations among the traits of first parity were high (0.55 to 0.99). From the results we could conclude that optimum strategy to improve the Sahiwal cattle further would be selecting the animals based on their first lactation 305dMY. Option top include the significant SNP in selection criteria can be explored. Taken together, a 2-stage selection approach, select Sahiwal animals early for the SNP and then on the basis of first lactation 305dMY will help to save resources.

Does hereditary angioedema make COVID-19 worse?

The coronavirus disease 2019 (COVID-19) pandemic has spread rapidly worldwide. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, enters host cells via angiotensin-converting enzyme 2 (ACE2) and depletes ACE2, which is necessary for bradykinin metabolism. The depletion of ACE2 results in the accumulation of des-Arg (9)-bradykinin and possible bradykinin, both of which bind to bradykinin receptors and induce vasodilation, lung injury, and inflammation. It is well known that an overactivated contact system and excessive production of bradykinin comprise the key mechanisms that drive the pathogenesis of hereditary angioedema (HAE). It is reasonable to speculate that COVID-19 may increase disease activity in patients with HAE and vice versa. In this review, we explore the potential interactions between COVID-19 and HAE in terms of the contact system, the complement system, cytokine release, increased T helper 17 cells, and hematologic abnormalities. We conclude with the hypothesis that comorbidity with HAE might favor COVID-19 progression and may worsen its outcomes, while COVID-19 might in turn aggravate pre-existing HAE and prompt the onset of HAE in asymptomatic carriers of HAE-related mutations. Based on the pathophysiologic links, we suggest that long-term prophylaxis should be considered in patients with HAE at risk of SARS-CoV-2 infection, especially the prophylactic use of C1 inhibitor and lanadelumab and that HAE patients must have medications for acute attacks of angioedema. Additionally, therapeutic strategies employed in HAE should be considered for the treatment of COVID-19, and clinical trials should be performed.

The central role of endothelium in hereditary angioedema due to C1 inhibitor deficiency

An impairment of the endothelial barrier function underlies a wide spectrum of pathological conditions. Hereditary angioedema due to C1-inhibitor deficiency (C1-INH-HAE) can be considered the "pathophysiological and clinical paradigm" of Paroxysmal Permeability Diseases (PPDs), conditions characterized by recurrent transient primitively functional alteration of the endothelial sieving properties, not due to inflammatory-ischemic-degenerative injury and completely reversible after the acute flare. It is a rare yet probably still underdiagnosed disease which presents with localized, non-pitting swelling of the skin and submucosal tissues of the upper respiratory and gastrointestinal tracts, without significant wheals or pruritus. The present review addresses the pathophysiology of C1-INH-HAE with a focus on the crucial role of the endothelium during contact and kallikrein/kinin system (CAS and KKS) activation, currently available and emerging biomarkers, methods applied to get new insights into the mechanisms underlying the disease (2D, 3D and in vivo systems), new promising investigation techniques (autonomic nervous system analysis, capillaroscopy, flow-mediated dilation method, non-invasive finger plethysmography). Hints are given to the binding of C1-INH to endothelial cells. Finally, crucial issues as the local vs systemic nature of CAS/KKS activation, the episodic nature of attacks vs constant C1-INH deficiency, pros and cons as well as future perspectives of available methodologies are briefly discussed.

The core genes involved in the promotion of depression in patients with ovarian cancer

The present study aimed to identify the core genes and pathways involved in depression in patients with ovarian cancer (OC) who suffer from high or low-grade depression. The dataset GSE9116 from Gene Expression Omnibus database was analyzed to identify differentially expressed genes (DEGs) in these patients. To elucidate how certain genes could promote depression in patients with OC, pathway crosstalk, protein-protein interaction (PPI) and comprehensive gene-pathway analyses were determined using WebGestalt, ToppGene and Search Tool for the Retrieval of Interacting Genes and gene ontology analysis. Key genes and pathways were extracted from the gene-pathway network, and gene expression and survival analysis were evaluated. A total of 93 DEGs were identified from GSE9116 dataset, including 84 upregulated genes and nine downregulated genes. The PPI, pathway crosstalk and comprehensive gene-pathway analyses highlighted C-C motif chemokine ligand 2 (CCL2), Fos proto-oncogene, AP-1 transcription factor subunit (FOS), serpin family E member 1 (SERPINE1) and serpin family G member 1 (SERPING1) as core genes involved in the promotion of depression in patients with OC. These core genes were involved in the following four pathways 'Ensemble of genes encoding ECM-associated proteins including ECM-affiliated proteins', 'ECM regulators and secreted factors', 'Ensemble of genes encoding extracellular matrix and extracellular matrix-associated proteins' and 'MAPK signaling pathway and IL-17 signaling pathway'. The results from gene expression and survival analysis demonstrated that these four key genes were upregulated in patients with OC and high-grade depression and could worsen patients' survival. These results suggested that CCL2, FOS, SERPINE1 and SERPING1 may serve a crucial role in the promotion of depression in patients with OC. This finding may provide novel markers for predicting and treating depression in patients with OC; however, the underlying mechanisms remain unknown and require further investigation.

The role of the complement system in hereditary angioedema

Hereditary angioedema (HAE) is a rare, but potentially life-threatening disorder, characterized by acute, recurring, and self-limiting edematous episodes of the face, extremities, trunk, genitals, upper airways, or the gastrointestinal tract. HAE may be caused by the deficiency of C1-inhibitor (C1-INH-HAE) but another type of the disease, hereditary angioedema with normal C1-INH function (nC1-INH-HAE) was also described. The patient population is quite heterogeneous as regards the location, frequency, and severity of edematous attacks, presenting large intra- and inter-individual variation. Here, we review the role of the complement system in the pathomechanism of HAE and also present an overview on the complement parameters having an importance in the diagnosis or in predicting the severity of HAE.

"Nuts and Bolts" of Laboratory Evaluation of Angioedema

Angioedema, as a distinct disease entity, often becomes a clinical challenge for physicians, because it may cause a life-threatening condition, whereas prompt and accurate laboratory diagnostics may not be available. Although the bedside diagnosis needs to be established based on clinical symptoms and signs, family history, and the therapeutic response, later, laboratory tests are available. Currently, only for five out of the nine different types of angioedema can be diagnosed by laboratory testing, and these occur only in a minority of the patient population. Hereditary angioedema with C1-inhibitor (C1-INH) deficiency type I can be diagnosed by the low C1-INH function and concentration, whereas in type II, C1-INH function is low, but its concentration is normal or even elevated. C1q concentration is normal in both forms. Acquired angioedema with C1-INH deficiency type I is characterized by the low C1-INH function and concentration; however, C1q concentration is also low, and autoantibodies against C1-INH cannot be detected. Complement profile of acquired angioedema with C1-INH deficiency type II is similar to that of type I, but in this form, autoantibodies against C1-INH are present. Hereditary angioedema due to a mutation of the coagulation factor XII can be diagnosed exclusively by mutation analysis of FXII gene. Diagnostic metrics are not available for idiopathic histaminergic acquired angioedema, idiopathic non-histaminergic acquired angioedema, acquired angioedema related to angiotensin-converting enzyme inhibitor, and hereditary angioedema of unknown origin; these angioedemas can be diagnosed by medical and family history, clinical symptoms, and therapeutic response and by excluding the forms previously described. Several potential biomarkers of angioedema are used to date only in research. In the future, they could be utilized into the clinical practice to improve the differential diagnosis, therapy, as well as the prognosis of angioedema.

Activation of the ficolin-lectin pathway during attacks of hereditary angioedema

BACKGROUND

The activation of plasma enzyme systems is insufficiently controlled in hereditary angioedema due to the deficiency of C1-inhibitor (C1-INH) (HAE-C1-INH). Recently, it was suggested that the ficolin-lectin pathway (ficolin-LP) might play a more dominant role than the mannose-binding lectin-lectin pathway in the pathomechanism of HAE-C1-INH.

OBJECTIVE

Because the role of the ficolin-LP during edematous attacks is still enigmatic, we analyzed its activity during such episodes.

METHODS

Thirty-five patients with HAE-C1-INH, who have experienced severe attacks on 106 occasions, were enrolled. We analyzed blood samples drawn during attacks, and obtained 35 samples from the same patients during symptom-free periods. The serum levels of ficolin-2, ficolin-3, MASP-2, ficolin-3/MASP-2 complex, C1-INH, and C4, as well as the extent of ficolin-3-mediated terminal complement complex (FCN3-TCC) deposition, were measured using ELISA-based methods.

RESULTS

Levels of MASP-2 and of the ficolin-3/MASP-2 complex were elevated (P < .0001 and .033, respectively), whereas that of FCN3-TCC was lower (P < .0001) during attacks than during the symptom-free period. During symptom-free periods, FCN3-TCC deposition was significantly related to concentrations of ficolin-3 (R = 0.2778; P = .0022), antigenic C1-INH (R = 0.3152; P = .0006), and C4 (R = 0.5307; P < .0001). Both ficolin-3 and MASP-2 levels correlated inversely with the time from the onset of the attack until blood sampling.

CONCLUSIONS

There is a marked heterogeneity of the pathomechanism and development of hereditary angioedema attacks in different patients. Our results suggest that the activation of the ficolin-LP may deplete the innately low level of C1-INH and thus, it may contribute to the uncontrolled activation of plasma cascade systems, and thereby to edema formation.

The role of ficolins and MASPs in hereditary angioedema due to C1-inhibitor deficiency

BACKGROUND AND OBJECTIVE

Hereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) causes disturbances in the complement system. However, the influence of HAE-C1-INH on the lectin pathway of complement is unresolved. Thus, we studied the main initiator molecules, enzymes and regulators in the lectin pathway in patients with HAE-C1-INH.

METHODS

The serum concentrations of ficolin-2, ficolin-3, MBL, MASP-2, MASP-3, and MAP-1 were measured during symptom-free periods in 91 patients with HAE-C1-INH, and in 100 healthy controls using sandwich ELISAs.

RESULTS

Compared with controls, the levels of ficolin-2 (p<0.0001) and MASP-2 (p=0.0238) were reduced, while the levels of MBL and MASP-3 were elevated (p=0.0028 and p<0.0001, respectively) in HAE-C1-INH patients. Ficolin-3 and MAP-1 levels did not differ significantly between the two groups. Ficolin-2 correlated with MASP-3 in patients (r=0.3443, p=0.0008), while these parameters showed an opposite relationship in controls (r=-0.4625, p<0.0001). In the patients, ficolin-3 correlated with MASP-2 (r=0.3698, p=0.001). Ficolin-2, -3, and MAP-1 correlated negatively with the annual requirement of plasma derived C1-INH concentrate (r=-0.2863, p=0.0059; r=-0.2654, p=0.0110 and r=-0.2501, p=0.0168, respectively). Ficolin-3 showed a negative correlation with the annual number of attacks (r=-0.2478, p=0.0179).

CONCLUSIONS

We found significant differences between patients and controls in the levels of some of the molecules belonging to the lectin complement pathway. Low concentrations of particularly ficolin-2 and -3 were inversely correlated with the severity of HAE-C1-INH, while this was not observed for MBL. This suggests a previously unrecognized involvement of the ficolin-dependent lectin complement pathway in the pathophysiology of HAE-C1-INH.

Cleavage of kininogen and subsequent bradykinin release by the complement component: mannose-binding lectin-associated serine protease (MASP)-1

Bradykinin (BK), generated from high-molecular-weight kininogen (HK) is the major mediator of swelling attacks in hereditary angioedema (HAE), a disease associated with C1-inhibitor deficiency. Plasma kallikrein, activated by factor XIIa, is responsible for most of HK cleavage. However other proteases, which activate during episodes of angioedema, might also contribute to BK production. The lectin pathway of the complement system activates after infection and oxidative stress on endothelial cells generating active serine proteases: MASP-1 and MASP-2. Our aim was to study whether activated MASPs are able to digest HK to release BK. Initially we were trying to find potential new substrates of MASP-1 in human plasma by differential gel electrophoresis, and we identified kininogen cleavage products by this proteomic approach. As a control, MASP-2 was included in the study in addition to MASP-1 and kallikrein. The proteolytic cleavage of HK by MASPs was followed by SDS-PAGE, and BK release was detected by HPLC. We showed that MASP-1 was able to cleave HK resulting in BK production. MASP-2 could also cleave HK but could not release BK. The cleavage pattern of MASPs is similar but not strictly identical to that of kallikrein. The catalytic efficiency of HK cleavage by a recombinant version of MASP-1 and MASP-2 was about 4.0×10² and 2.7×10² M⁻¹s⁻¹, respectively. C1-inhibitor, the major inhibitor of factor XIIa and kallikrein, also prevented the cleavage of HK by MASPs. In all, a new factor XII- and kallikrein-independent mechanism of bradykinin production by MASP-1 was demonstrated, which may contribute to the pro-inflammatory effect of the lectin pathway of complement and to the elevated bradykinin levels in HAE patients.

High levels of acute phase proteins and soluble 70 kDa heat shock proteins are independent and additive risk factors for mortality in colorectal cancer

Recently, we reported that high soluble Hsp70 (sHsp70) level was a significant predictor of mortality during an almost 3-year-long follow-up period in patients with colorectal cancer. This association was the strongest in the group of <70-year-old female patients as well as in those who were in a less advanced stage of the disease at baseline. According to these observations, measurement of the serum level of sHsp70 is a useful, stage-independent prognostic marker in colorectal cancer, especially in patients without distant metastasis. Since many literature data indicated that measurement of C-reactive protein (CRP) and other acute phase proteins (APPs) may also be suitable for predicting the mortality of patients with colorectal cancer, it seemed reasonable to study whether the effect of sHsp70 and other APPs are related or independent. In order to answer this question, we measured the concentrations of CRP as well as of other complement-related APPs (C1 inhibitor, C3, and C9) along with that of the MASP-2 complement component in the sera of 175 patients with colorectal cancer and known levels of sHsp70, which have been used in our previous study. High (above median) levels of CRP, C1 esterase inhibitor (C1-INH), and sHsp70 were found to be independently associated with poor patient survival, whereas no such association was observed with the other proteins tested. According to the adjusted Cox proportional hazards analysis, the additive effect of high sHsp70, CRP, and C1-INH levels on the survival of patients exceeded that of high sHsp70 alone, with a hazard ratio (HR) of 2.83 (1.13-70.9). In some subgroups of patients, such as in females [HR 4.80 (1.07-21.60)] or in ≤70-year-old patients [HR 11.53 (2.78-47.70)], even greater differences were obtained. These findings indicate that the clinical mortality-prediction value of combined measurements of sHsp70, CRP, and C1-INH with inexpensive methods can be very high, especially in specific subgroups of patients with colorectal cancer.

Angioedema beyond histamine: an educational case series

Angioedema constitutes an important clinical problem that can cause significant morbidity and mortality. Correct management requires a prompt recognition and treatment of the acute event and identification of the underlying cause. Many cases are caused by non-allergic reactions and do not result from mediator release by degranulating mast cells and basophils, but are related to accumulation of plasma and tissue bradykinin. This case series aims primarily to describe some important causes of non-allergic bradykinin-induced angioedema. Particular emphasis is put on clinical particularities, differential diagnosis, diagnostic approach and correct therapeutic management, as bradykinin-mediated angioedema is unresponsive to antihistamines.