Proteomics couples electrical remodelling to inflammation in a murine model of heart failure with sinus node dysfunction

AIMS

In patients with heart failure (HF), concomitant sinus node dysfunction (SND) is an important predictor of mortality, yet its molecular underpinnings are poorly understood. Using proteomics, this study aimed to dissect the protein and phosphorylation remodelling within the sinus node in an animal model of HF with concurrent SND.

METHODS AND RESULTS

We acquired deep sinus node proteomes and phosphoproteomes in mice with heart failure and SND and report extensive remodelling. Intersecting the measured (phospho)proteome changes with human genomics pharmacovigilance data, highlighted downregulated proteins involved in electrical activity such as the pacemaker ion channel, Hcn4. We confirmed the importance of ion channel downregulation for sinus node physiology using computer modelling. Guided by the proteomics data, we hypothesized that an inflammatory response may drive the electrophysiological remodeling underlying SND in heart failure. In support of this, experimentally induced inflammation downregulated Hcn4 and slowed pacemaking in the isolated sinus node. From the proteomics data we identified proinflammatory cytokine-like protein galectin-3 as a potential target to mitigate the effect. Indeed, in vivo suppression of galectin-3 in the animal model of heart failure prevented SND.

CONCLUSION

Collectively, we outline the protein and phosphorylation remodeling of SND in heart failure, we highlight a role for inflammation in electrophysiological remodelling of the sinus node, and we present galectin-3 signalling as a target to ameliorate SND in heart failure.

Ligand-Dependent Mechanisms of C-C Chemokine Receptor 5 (CCR5) Trafficking Revealed by APEX2 Proximity Labeling Proteomics

CC chemokine receptor 5 (CCR5) contributes to inflammatory responses by driving cell migration and scavenging chemokine to shape directional chemokine gradients. A drug against CCR5 has been approved for blocking HIV entry into cells. However, targeting CCR5 for the treatment of inflammatory diseases and cancer has had limited success because of the complex biology and pharmacology of this receptor. CCR5 is activated by many natural and engineered chemokines that elicit distinct receptor signaling and trafficking responses, including some that sequester the receptor inside the cell. The sequestration phenomenon may be therapeutically exploitable, but the mechanisms by which different ligands traffic CCR5 to different cellular locations are poorly understood. Here we employed live cell ascorbic acid peroxidase proximity labeling and quantitative mass spectrometry proteomics for unbiased discovery of temporally resolved protein neighborhoods of CCR5 following stimulation with its endogenous agonist, CCL5, and two CCL5 variants that promote intracellular retention of the receptor. Along with targeted pharmacological assays, the data reveals distinct ligand-dependent CCR5 trafficking patterns with temporal resolution. All three chemokines internalize CCR5 via β-arrestin- dependent, clathrin-mediated endocytosis but to different extents, with different kinetics and with varying dependencies on GPCR kinase subtypes. The agonists differ in their ability to target the receptor to lysosomes for degradation, as well as to the Golgi compartment and the trans-Golgi network, and these trafficking patterns translate into distinct levels of ligand scavenging. The results provide insight into the molecular mechanisms behind CCR5 intracellular sequestration and suggest actionable patterns for the development of chemokine-based CCR5 targeting molecules.

Significance Statement

CCR5 plays a crucial role in the immune system and is important in numerous physiological and pathological processes such as inflammation, cancer and HIV transmission. Along with its functional diversity, different CCR5 ligands can induce distinct receptor signaling responses and trafficking behaviors; the latter includes intracellular receptor sequestration which offers a potential therapeutic strategy for inhibiting CCR5 function. Using time-resolved proximity labeling proteomics and targeted pharmacological experiments, this study reveals the molecular basis for receptor sequestration including information that can be exploited for the development of CCR5 targeting molecules that promote retention of the receptor inside the cell.

Meditation-induced bloodborne factors as an adjuvant treatment to COVID-19 disease

The COVID-19 pandemic has resulted in significant morbidity and mortality worldwide. Management of the pandemic has relied mainly on SARS-CoV-2 vaccines, while alternative approaches such as meditation, shown to improve immunity, have been largely unexplored. Here, we probe the relationship between meditation and COVID-19 disease and directly test the impact of meditation on the induction of a blood environment that modulates viral infection. We found a significant inverse correlation between length of meditation practice and SARS-CoV-2 infection as well as accelerated resolution of symptomology of those infected. A meditation "dosing" effect was also observed. In cultured human lung cells, blood from experienced meditators induced factors that prevented entry of pseudotyped viruses for SARS-CoV-2 spike protein of both the wild-type Wuhan-1 virus and the Delta variant. We identified and validated SERPINA5, a serine protease inhibitor, as one possible protein factor in the blood of meditators that is necessary and sufficient for limiting pseudovirus entry into cells. In summary, we conclude that meditation can enhance resiliency to viral infection and may serve as a possible adjuvant therapy in the management of the COVID-19 pandemic.

Outlining cardiac ion channel protein interactors and their signature in the human electrocardiogram

Protein-protein interactions are essential for normal cellular processes and signaling events. Defining these interaction networks is therefore crucial for understanding complex cellular functions and interpretation of disease-associated gene variants. We need to build a comprehensive picture of the interactions, their affinities and interdependencies in the specific organ to decipher hitherto poorly understood signaling mechanisms through ion channels. Here we report the experimental identification of the ensemble of protein interactors for 13 types of ion channels in murine cardiac tissue. Of these, we validated the functional importance of ten interactors on cardiac electrophysiology through genetic knockouts in zebrafish, gene silencing in mice, super-resolution microscopy and patch clamp experiments. Furthermore, we establish a computational framework to reconstruct human cardiomyocyte ion channel networks from deep proteome mapping of human heart tissue and human heart single-cell gene expression data. Finally, we integrate the ion channel interactome with human population genetics data to identify proteins that influence the electrocardiogram (ECG). We demonstrate that the combined channel network is enriched for proteins influencing the ECG, with 44% of the network proteins significantly associated with an ECG phenotype. Altogether, we define interactomes of 13 major cardiac ion channels, contextualize their relevance to human electrophysiology and validate functional roles of ten interactors, including two regulators of the sodium current (epsin-2 and gelsolin). Overall, our data provide a roadmap for our understanding of the molecular machinery that regulates cardiac electrophysiology.

Proteome allocation is linked to transcriptional regulation through a modularized transcriptome

It has proved challenging to quantitatively relate the proteome to the transcriptome on a per-gene basis. Recent advances in data analytics have enabled a biologically meaningful modularization of the bacterial transcriptome. We thus investigated whether matched datasets of transcriptomes and proteomes from bacteria under diverse conditions could be modularized in the same way to reveal novel relationships between their compositions. We found that; 1) the modules of the proteome and the transcriptome are comprised of a similar list of gene products, 2) the modules in the proteome often represent combinations of modules from the transcriptome, 3) known transcriptional and post-translational regulation is reflected in differences between two sets of modules, allowing for knowledge-mapping when interpreting module functions, and 4) through statistical modeling, absolute proteome allocation can be inferred from the transcriptome alone. Quantitative and knowledge-based relationships can thus be found at the genome-scale between the proteome and transcriptome in bacteria.

AB0276 HOW FAST CAN METHOTREXATE BE ESCALATED IN RHEUMATOID ARTHRITIS? A MULTICENTRE, PARALLEL-GROUP RANDOMIZED CONTROLLED TRIAL (MEIRA)

Background:

Literature regarding the optimal dose escalation strategy of methotrexate (MTX) in RA is scant and ambiguous (1). Concerns regarding the safety of rapid escalation may lead to delayed attainment of the optimal dose and treatment target.

Objectives:

To compare the efficacy, safety and tolerability of fast versus usual dose escalation of oral MTX in RA.

Methods:

This multicenter, open-label (assessor blinded) RCT included patients with active RA (SJC≥2 and TJC≥4) aged 18-55 years, not on DMARDs (except HCQ and/or low-dose prednisolone) and with disease duration <5 years. Patients were randomized 1:1 into two groups with the same starting dose of oral MTX (15 mg/week), but escalated either by 5 mg every 2 weeks (fast escalation group) or 5 mg every 4 weeks (usual escalation group), till a maximum of 25 mg/wk. Primary outcome was proportion of EULAR good responders at 16 weeks. Secondary outcomes were change in DAS28-3 and EULAR responders (good or moderate) at 8 and 16 weeks, change in Indian HAQ at 16 weeks, and symptomatic (questionnaire based) and laboratory adverse effects over 16 weeks. RBC MTX polyglutamate-3 levels were measured using HPLC in both groups. There was an open-label extension phase till 24 weeks (use of other DMARDs was permitted beyond 16 weeks if target was not met), and DAS28-3 at 24 weeks was compared.

Trial Reg: CTRI/2018/12/016549

Results:

178 patients (mean age 39.8 (8.6) years, 84% females) with mean disease duration of 1.9 (1.4) years were randomized (89 in each group). Mean DAS28ESR-3 and DAS28CRP-3 at enrollment were 6.3 (0.9) and 5.4 (1.1). At 16 weeks, there was no significant difference in good EULAR response by DAS28ESR-3 (5.6, 7.9%, p=0.9) or DAS28CRP-3 (28.1, 22.5%, p=0.8) between the two groups (Figure 1). The change in DAS28-ESR-3 at 8, 16 and 24 weeks (or by DASCRP-3, not shown) and improvement in HAQ at 16 weeks were also not significantly different (Table 1). Notably, there was no significant difference in symptomatic GI or CNS adverse effects, incidence of cytopenia, transaminitis or rates of drug discontinuation. RBC MTX polyglutamate-3 levels at 8 and 16 weeks were also similar (Table 1).

Table 1.

Key secondary efficacy and safety outcomes

ParameterUsualFastp-valueEfficacyDelta DAS28-ESR-3 (Mean±SD) -8 wk  -ITT (n=178)-0.9 ± 1.0-0.8 ± 0.90.5  -PP (n=139)-1.2 ± 1.0-1.1 ± 1.00.5 -16 wk  -ITT-1.3 ± 1.1-1.3 ± 1.00.9  -PP-1.6 ± 1.1-1.6 ± 0.91 -24 wk  -ITT-1.6 ± 1.3-1.5 ± 1.10.3  -PP-2.1 ± 1.2-1.8 ± 1.10.14Delta Indian HAQ (16 wk)-0.7 ± 0.6-0.8 ± 0.60.2Adverse effectsSerious AE00-Death00-Symptomatic AE ever* n (%)Vomiting7 (8)7 (8)1Nausea22 (26)26 (30)0.5Stomach ache16 (19)17 (20)0.9Loss of appetite/bad taste21 (25)27 (31)0.3Lethargy20 (24)21 (25)1Dizziness19 (23)16 (19)0.5Irritability/anxiety14 (16)14 (16)1Laboratory AE ever* [n/N times done (%)]Transaminitis episodes (>40IU/L)52/224 (23)52/219 (24)0.9  -Significant (>80 IU/L)5/224 (2)8/219 (4)0.4Thrombocytopenia episodes (<150000/uL)10/224 (5)13/218 (6)0.5 -Significant (<100000/uL)2/224 (1)2/218 (1)1Leucopenia episodes (<4000/uL)2/224 (1)3/220 (1.5)0.8 -Significant (<3500/uL)1/224 (0.5)2/220 (1)0.8Methotrexate levelsMTX-polyglutamate-3 (nmol/L)-8 wk25.8 ± 10.526.9 ± 13.60.6-16 wk40.7 ± 20.940.1 ± 23.40.9

*Ever=any time during the study

ITT= intention-to-treat, PP=per-protocol, AE=adverse effect

Figure 1.

EULAR response and change in DAS28ESR-3 over time

Conclusion:

A faster escalation of MTX (5 mg every 2 weeks) reaching 25 mg/week by 4 weeks did not have a significantly higher rate of adverse effects (symptomatic or laboratory) compared to an escalation by 5 mg every 4 weeks. Although not more efficacious, it may shorten the time to recognize MTX failure, and optimize treat-to-target.

References:

[1]Visser K, Katchamart W, Loza E, et al. Multinational evidence-based recommendations for the use of methotrexate in rheumatic disorders with a focus on RA: integrating systematic literature research and expert opinion of a broad international panel of rheumatologists in the 3E Initiative. Ann Rheum Dis. 2009;68(7):1086–93

Disclosure of Interests:

None declared

Multiple nerve transfers for the reanimation of shoulder and elbow functions in irreparable C5, C6 and upper truncal lesions of the brachial plexus

In irreparable C5, C6 spinal nerve and upper truncal injuries the proximal root stumps are not available for grafting, hence repair is based on nerve transfer or neurotization. Between Feb 2004 and May 2006, 23 patients with irreparable C5, C6 or upper truncal injuries of the Brachial Plexus underwent multiple nerve transfers to restore the shoulder and elbow functions. Most of them (16 patients) sustained injury following motor cycle accidents. The average denervation period was 5.3 months. Shoulder function was restored by transfer of distal part of spinal accessory nerve to suprascapular nerve, and transfer of radial nerve branch to long head of triceps to the anterior branch of axillary nerve. Elbow function was restored by transfers of ulnar and median nerve fascicles to the biceps and brachialis motor branches of musculocutaneous nerve. All patients recovered shoulder abduction and external rotation; 7 scored M4 and 16 scored M3. Range of abduction averaged 1230(range, 800-1700). Full elbow flexion was restored in all 23 patients; 15 scored M4 and 8 scored M3. Patients with excellent results could lift 5 kgs of weight. Selective nerve transfers close to the target muscle provide an early and good return of functions. There is negligible morbidity in donor nerves. These intraplexal transfers are suitable in all cases of upper brachial plexus injuries.

Characterization of phenolic compounds in some Indian mango cultivars

Mangoes (Mangifera indica) are rich in phenolic acids as detected by high-performance liquid chromatography. The phenolics have prominent medicinal properties. Among six important commercial mango cultivars (Deshi, Langra, Chausa, Mallika, Dashahari and Amrapali) tannic acid was maximal in Mallika, while gallic acid was maximal in Chausa and all other varieties. Caffeic acid was maximal in Langra followed by Chausa and Amrapali. Many of the pharmacological properties attributed to mango might be due to the presence of phenolic acids in fairly significant amounts.

Chemotaxonomic variability in Zizyphus mouritiana varieties and its pharmacological properties in relation to human health

Twenty varieties of ber (Zizyphus mouritiana), namely umaran, katha, bilayati, kaithli, ZG-3, gola, safeda rohtak, takadi, tikari, banarasi karaka, seo, sonaur-2, sonaur-3, ilaichi, mundia murahra, pathan, kakrola gola, seb, golden yellow and chhuhara, were investigated for the presence of phenolic acids in stem bark, leaves and fruits using high performance liquid chromatograph. Results indicated the presence of tannic (retention time (Rt.) 2.76 min), gallic (Rt. 2.86 min), caffeic (Rt. 3.12 min), vanillic (Rt. 3.26 min), ferulic (Rt. 3.42 min), chlorogenic (Rt. 4.16 min) and cinnamic acids (Rt. 4.45 min) in varying amounts in different parts in of these varieties. In fruits of seven varieties, namely, kaithly, sonaur-2, sonaur-3, mundia murahra, pathan, golden yellow and chhuhara, oxalic acid (Rt. 3.00 min) was also detected. Pharmacological properties of phenolic acids of fruits in relation to human health and the possible implications of different phenolic acids in chemotaxonomy of different varieties of ber are discussed.

Liquid chromatographic-electrospray tandem mass spectrometric method for the quantification of nimodipine in human plasma

A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of nimodipine, a calcium channel blocker, in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse phase C18 column and analyzed by MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 419/343 for nimodipine and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 0.2-50 ng/mL for nimodipine in human plasma. The lower limit of quantification was 200 pg/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 3 min for each sample made it possible to analyze more than 250 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.

Antifungal Activity of Narceine Methyl Ester and Narceine Isolated from Corydalis longipes Against Some Phytopathogenic Fungi

Narceine methyl ester and narceine are potent alkaloids which were isolated from Corydalis longipes were found effective in vitro at very low concentration, i.e., 100~500 ppm against spore germination of some test plant pathogenic fungi (Alternaria solani, A. tagetica, Cercospora abelmoschi, Curvularia maculans, Erysiphe cichoracearum, E. pisi, Fusarium udum, Helminthosporium oryzae, H. penniseti, Ustilago cynodontis). Among the test, phytopathogens the spores of F. udum, C. maculans and H. penniseti were highly sensitive at 200 ppm. However, spores of E. pisi, A. solani and A. tagetica were less sensitive at low concentration followed by other test fungi. Most of the fungi showed zero or nearly zero percent spore germination at 400 and 500 ppm.

Antifungal Activity of Nor-securinine Against Some Phytopathogenic Fungi

Crude extracts and active principles from medicinal plants have shown potential role in controlling plant diseases in glasshouses as well as in fields as one of the safest and ecofriendly methods. The effect of nor-securinine (an alkaloid) isolated from Phyllanthus amarus has been seen against spore germination of some fungi (Alternaria brassicae, A. solani, Curvularia pennisetti, Curvularia sp., Erysiphe pisi, Helminthosporium frumentacei) as well as pea powdery mildew (Erysiphe pisi) under glasshouse conditions. The sensitivity of fungi to nor-securinine varied considerably. Nor-securinine was effective against most of the fungi. H. frumentacei was more sensitive even at the lowest concentration (1,000 µg/ml). Likewise conidia of E. pisi were also inhibited in partially or completely appressorium formation. Pre-inoculation treatment showed greater efficacy than post-inoculation in inhibiting powdery mildew development on pea plants in a glasshouse. Maximum inhibition occurred at 2000 µg/ml.

Phenolic acids in neem (Azadirachta indica): a major pre-existing secondary metabolites

High Performance Liquid Chromatographic (HPLC) analyses of various parts (fresh and dry bark of stem, mature and tender leaves, flower and different parts of fruit, i.e., raw and ripe fruit epicarp, mesocarp and seed) of neem (Azadirachta indica), which occupies an important place in socio-cultural-religious life in Indian communities, indicate that neem is rich in pre-existing secondary metabolites (phenolic acids). Dry bark showed only tannic acid but in fresh bark three phenolic acids were observed, i.e., gallic, tannic, and ferulic acids. In tender leaves only gallic and ferulic acids were detected, but the levels of these phenolic acids in mature leaves were about three times and fifty times greater, respectively. Flowers had only two phenolic acids in which gallic acid was maximum followed by chlorogenic acid. The level of phenolic acid was maximum in seeds followed by epicarp and pulp. In raw and ripe fruit seeds four phenolic acids were detected. Raw fruit seeds were rich in phenolic acids than ripe fruit seeds. Fruit epicarp was relatively richer than seed, seed pulp and flowers of the plants. Neem flowers were also rich in gallic and chlorogenic acids.

Two plant alkaloids isolated from Corydalis longipes as potential antifungal agents

The alkaloids N-methylhydrasteine hydroxylactam and 1-methoxyberberine chloride were isolated from Corydalis longipes. Both alkaloids showed high efficacy individually (in concentration of 50-150 ppm) and also in a 1:1 mixture against spore germination of some fungi, viz. Alternaria alternata, A. brassicae, Curvularia maculans, Curvularia sp., Colletotrichum gloeosporioides, Colletotrichum sp., Helminthosporium speciferum, H. pennisetti, Helminthosporium sp., and Ustilago cynodontis. The antifungal effect of single compounds was dose-dependent. If the mutual ratio of the two components in the mixture was changed from 1:1 to a major content of any of the two compounds, the inhibitory effect on spore germination decreased.

Investigation on the phenolics of some spices having pharmacotherapeuthic properties

Spices are an important group of agricultural commodities being used by many civilizations all over the world to aid flavor, taste and nutritional values in the food. In traditional medical systems, their ability to heal various physical, mental and emotional problems has widely been reported. With this view, HPLC analysis was performed to estimate phenolic acids in 21 spices (asafetida, Bishop's weed, black mustard, coriander, cinnamon, clove, curry leaf, cumin black, cumin, fennel, fenugreek, garlic, ginger, Indian cassia, Indian dill or dill large cardamom, onion, saffron, tamarind, true cardamom, yellow mustard) commonly used in India in different forms. In all, 7 phenolic acids; viz., tannic, gallic, caffeic, cinnamic, chlorogenic, ferulic and vanillic acids could be identified on the basis of their retention time with standard compounds and co-chromatography. Several parts of the spices, for instance, seeds, leaves, barks, rhizomes, latex, stigmas, floral buds and modified stems were used in the study. Maximum amount of tannic and gallic acids was observed in black mustard and clove. Caffeic, chlorogenic and ferulic acids were found maximum in cumin while vanillic and cinnamic acids in onion seeds. The spices are known to significantly contribute to the flavor, taste, and medicinal properties of food because of phenolics.

Efficacy of alkaloid (-)-corypalmine against spore germination of some fungi

Inhibition activity of the alkaloid (-)-corypalmine on spore germination of plant pathogenic and saprophytic fungi (Alternaria solani, A brassicicola, A. brassicae, A. melongenae, Curvularia pallescens, C. lunata, C. maculans, Curvularisa sp., Colletotrichum sp., Helminthosporium speciferum, H. frumentacei, H. pennisetti, Heterosporium sp., Penicillum sp., Ustilago cynodontis) was determined. Spore germination of all the tested fungi was inhibited, Heterosporium sp. and Ustilago cynodontis being the most sensitive (complete inhibition of spore germination was observed at the very low concentration of 200 ppm). Curvularia palliscens, C. maculans and Curvularia sp. were less sensitive; complete inhibition of spore germination occurred at 400 ppm.