Anti-HSV activity of nectin-1-derived peptides targeting HSV gD: an in-silico and in-vitro approach.

Herpes simplex virus (HSV) infections affect a wide range of the global population. The emergence of resistance to the existing anti-HSV therapy highlights the necessity for an innovative strategy. The interaction of HSV gD with its main host receptor nectin-1 is a potential target for new antiviral drugs. The aim of this study was to develop a peptide derived from nectin-1 targeting HSV gD using the in-silico method and evaluate them for anti-HSV activity. Residues 59-133 of the Nectin-1 V-domain constitute the interaction interface with HSV gD. Bioinformatic tools viz., PEP-FOLD3, ClusPro 2.0, HawkDock and Desmond were used to model the peptide and confirm its binding specificity with HSV gD protein. The peptides with potential interactions were custom synthesized and anti-HSV activity was evaluated in vitro against HSV-1 and HSV-2 by CPE inhibition assay. Five peptide sequences were identified as exhibiting good interaction with HSV-gD proteins. Among them, peptide N1 (residues 76-90) offered maximum protection against HSV-1 (66.57%) and HSV-2 (71.12%) infections. Modification of the identified peptide through peptidomimetic approaches may further enhance the activity and stability of the identified peptide.Communicated by Ramaswamy H. Sarma.

Revamped mini-αA-crystallin showed improved skin permeation and therapeutic activity against melittin-induced toxicity.

Melittin is honey bee venom's primary and most toxic pharmacologically active component. Melittin causes haemolysis, lymphocyte lysis, long-term pain, localised inflammation followed by rhabdomyolysis, and severe renal failure. Renal failure or cardiovascular complications could lead to the victim's death. Severe honey bee bites are treated with general medication involving antihistaminic, anti-inflammatory, and analgesic drugs, as a specific treatment option is unavailable. An earlier study showed the anti-hemolysis and anti-lymphocyte lysis activity of mini- αA-crystallin (MAC), a peptide derived from human eye lens alpha-crystallin. MAC's use has often been restricted despite its high therapeutic potential due to its poor skin permeability. This study compared the skin permeation, anti-inflammatory and analgesic activities of natural peptide MAC and its modified version (MAC-GRD) formed by attaching cell-penetrating peptide (CPP) and GRD amino residues into MAC. Gel formulations were prepared for MAC and MAC-GRD peptides using carbopol (1% w/w), Tween 80 (1%), and ethanol (10%). An ex-vivo skin permeation study was performed using a vertical-type Franz diffusion apparatus. Preclinical in-vivo experiments were conducted to compare the native and modified peptide formulations against melittin-induced toxicity in Wistar rats. MAC gel, MAC-GRD gel and 1% hydrocortisone cream significantly reduced the melittin-induced writhing (20.16 ± 0.792) response in rats with 15.16 ± 0.47, 11.16 ± 0.477 and 12.66 ± 0.66 wriths, respectively. There was a significant reduction in melittin-induced inflammation when MAC-GRD gel was applied immediately after melittin administration. At 0.5, 1, 3, and 5 h, the MAC-GRD-treated rat paws were 0.9 ± 0.043 mm, 0.750 ± 0.037 mm, 0.167 ± 0.0070 mm, and 0.133 ± 0.031 mm thick. Administration of melittin resulted in reduced GSH (antioxidant) levels (47.33 ± 0.760 µg/mg). However, treatment with MAC-GRD gel (71.167 ± 0.601 µg/mg), MAC gel (65.167 ± 1.138 µg/mg), and 1% hydrocortisone (68.33 ± 0.667 µg/mg) significantly increased the antioxidant enzyme levels. MAC-GRD gel significantly reduced the elevated MDA levels (6.933 ± 0.049 nmol/mg) compared to the melittin group (12.533 ± 0.126 nmol/mg), followed by the 1% hydrocortisone (7.367 ± 0.049 nmol/mg) and MAC gel (7.917 ± 0.048 nmol/mg). MAC-GRD demonstrated more skin permeability and superior anti-inflammatory, analgesic, and antioxidant activities when compared to MAC gel. When compared to standard 1% hydrocortisone cream, MAC-GRD had better anti-inflammatory, analgesic, antioxidant, and comparable action in anti-oxidant restoration against melittin. These findings suggest that the developed MAC-GRD gel formulation could help to treat severe cases of honey bee stings.

Methylglyoxal Induced Modifications to Stabilize Therapeutic Proteins: A Review.

Therapeutic proteins are potent, fast-acting drugs that are highly effective in treating various conditions. Medicinal protein usage has increased in the past 10 years, and it will evolve further as we better understand disease molecular pathways. However, it is associated with high processing costs, limited stability, difficulty in being administered as an oral medication, and the inability of large proteins to penetrate tissue and reach their target locations. Many methods have been developed to overcome the problems with the stability and chaperone activity of therapeutic proteins, viz., the addition of external agents (changing the properties of the surrounding solvent by using stabilizing excipients, e.g., amino acids, sugars, polyols) and internal agents (chemical modifications that influence its structural properties, e.g., mutations, glycosylation). However, these methods must completely clear protein instability and chaperone issues. There is still much work to be done on finetuning chaperone proteins to increase their biological efficacy and stability. Methylglyoxal (MGO), a potent dicarbonyl compound, reacts with proteins and forms covalent cross-links. Much research on MGO scavengers has been conducted since they are known to alter protein structure, which may result in alterations in biological activity and stability. MGO is naturally produced within our body, however, its impact on chaperones and protein stability needs to be better understood and seems to vary based on concentration. This review highlights the efforts of several research groups on the effect of MGO on various proteins. It also addresses the impact of MGO on a client protein, α-crystallin, to understand the potential solutions to the protein's chaperone and stability problems.

A critical review on antiviral peptides derived from viral glycoproteins and host receptors to decoy herpes simplex virus.

The health of the human population has been continuously challenged by viral infections. Herpes simplex virus (HSV) is one of the common causes of illness and can lead to death in immunocompromised patients. Existing anti-HSV therapies are not completely successful in eliminating the infection due to anti-viral drug resistance, ineffectiveness against the latent virus and high toxicity over prolonged use. There is a need to update our knowledge of the current challenges faced in anti-HSV therapeutics and realize the necessity of developing alternative treatment approaches. Protein therapeutics are now being explored as a novel approach due to their high specificity and low toxicity. This review highlights the significance of HSV viral glycoproteins and host receptors in the pathogenesis of HSV infection. Proteins or peptides derived from HSV glycoproteins gC, gB, gD, gH and host cell receptors (HSPG, nectin and HVEM) that act as decoys to inhibit HSV attachment, entry, or fusion have been discussed. Few researchers have tried to improve the efficacy and stability of the identified peptides by modifying them using a peptidomimetic approach. With these efforts, we think developing an alternative treatment option for immunocompromised patients and drug-resistant organisms is not far off.

Small extracellular vesicle-loaded bevacizumab reduces the frequency of intravitreal injection required for diabetic retinopathy.

Diabetic retinopathy (DR) is associated with retinal neovascularization, hard exudates, inflammation, oxidative stress and cell death, leading to vision loss. Anti-vascular endothelial growth factor (Anti-VEGF) therapy through repeated intravitreal injections is an established treatment for reducing VEGF levels in the retina for inhibiting neovascularization and leakage of hard exudates to prevent vision loss. Although anti-VEGF therapy has several clinical benefits, its monthly injection potentially causes devastating ocular complications, including trauma, intraocular hemorrhage, retinal detachment, endophthalmitis, etc. Methods: As mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) demonstrated safety in clinical studies, we have tested the efficacy of MSC-derived small EVs (MSC-sEVs) loaded anti-VEGF drug bevacizumab in a rat model of DR. Results: The study identified a clinically significant finding that sEV loaded with bevacizumab reduces the frequency of intravitreal injection required for treating diabetic retinopathy. The sustained effect is observed from the reduced levels of VEGF, exudates and leukostasis for more than two months following intravitreal injection of sEV loaded with bevacizumab, while bevacizumab alone could maintain reduced levels for about one month. Furthermore, retinal cell death was consistently lower in this period than only bevacizumab. Conclusion: This study provided significant evidence for the prolonged benefits of sEVs as a drug delivery system. Also, EV-mediated drug delivery systems could be considered for clinical application of retinal diseases as they maintain vitreous clarity in the light path due to their composition being similar to cells.

Interplay between stress and immunity triggers herpes zoster infection in COVID-19 patients: a review.

Coronavirus disease 2019 (COVID-19) is a potential health threat in the highly mobile society of the world. There are also concerns regarding the occurrence of co-infections occurring in COVID-19 patients. Herpes zoster (HZ) is currently being reported as a co-infection in COVID-19 patients. It is a varicella-zoster virus induced viral infection affecting older and immunocompromised individuals. Reactivation of HZ infection in COVID-19 patients are emerging and the mechanism of reactivation is still unknown. The most convincing argument is that increased psychological and immunological stress leads to HZ in COVID-19 patients; this review justifies this argument.

Melittin, a honeybee venom derived peptide for the treatment of chemotherapy-induced peripheral neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of cancer treatment which involves sensory and motor nerve dysfunction. Severe CIPN has been reported in around 5% of patients treated with single and up to 38% of patients treated with multiple chemotherapeutic agents. Present medications available for CIPN are the use of opioids, nonsteroidal anti-inflammatory agents, and tricyclic antidepressants, which are only marginally effective in treating neuropathic symptoms. In reality, symptom reappears after these drugs are discontinued. The pathogenesis of CIPN has not been sufficiently recognized and methods for the prevention and treatment of CIPN remain vulnerable to therapeutic problems. It has witnessed that the present medicines available for the disease offer only symptomatic relief for the short term and have severe adverse side effects. There is no standard treatment protocol for preventing, reducing, and treating CIPN. Therefore, there is a need to develop curative therapy that can be used to treat this complication. Melittin is the main pharmacological active constituent of honeybee venom and has therapeutic values including in chemotherapeutic-induced peripheral neuropathy. It has been shown that melittin and whole honey bee venom are effective in treating paclitaxel and oxaliplatin-induced peripheral neuropathy. The use of melittin against peripheral neuropathy caused by chemotherapy has been limited despite having strong therapeutic efficacy against the disease. Melittin mediated haemolysis is the key reason to restrict its use. In our study, it is found that α-Crystallin (an eye lens protein) is capable of inhibiting melittin-induced haemolysis which gives hope of using an appropriate combination of melittin and α-Crystallin in the treatment of CIPN. The review summarizes the efforts made by different research groups to address the concern with melittin in the treatment of chemotherapeutic-induced neuropathy. It also focuses on the possible approaches to overcome melittin-induced haemolysis.

Anti-Inflammatory Activity of Human Lens Crystallin Derived Peptide.

BACKGROUND: Inflammation has become the culmination point for several chronic diseases like skin diseases, asthma, neurological disorders, cancer, and cardiovascular disorders. Mini αA-crystallin peptide, identified from a highly conserved region of human lens protein αA-crystallin, is known to have a chaperone-like function; hence, it has generated interest in exploring the anti-inflammatory potential of the peptide. OBJECTIVE: The objective of the study was to evaluate the anti-inflammatory potential of mini αA chaperones using in vitro, ex-vivo, and in vivo models. METHODS: The peptide was tested for its phosphodiestarase4 B inhibition, anti-inflammatory and free radical scavenging abilities in HaCaT cells. Carbopol gel formulations with varying concentrations of mini αA-crystallin peptide and diclofenac sodium were prepared and optimized. Skin permeation studies of prepared formulations were carried out on excised abdominal skin of Wistar rat using a vertical type diffusion cell. Carrageenan induced rat paw oedema model was used for determining the anti-inflammatory potential of the peptide in prepared gel formulation with or without diclofenac sodium. RESULTS: The peptide exhibited appreciable free radical scavenging and weak PDE4B inhibition. Gel formulation with 1% Tween-80, 1% carbopol, and 10% ethanol showed better permeation compared to other formulations. The in vitro skin permeation studies revealed good improvement in permeation characteristics of diclofenac and peptide from the gels. The peptide was retained within the skin tissue, which is an ideal requirement for the delivery of an anti-inflammatory topical formulation. In preclinical anti-inflammatory studies, gel formulation containing mini αA-peptide and diclofenac sodium showed a significant decrease in paw volume compared to other combinations tested. CONCLUSION: The study revealed the additive effect in anti-inflammatory activity by combining mini-αA peptide and diclofenac sodium which effectively reduced the inflammation.