The success of allogeneic hematopoietic cell transplantation is limited by acute graft-versus-host disease (GvHD), a severe complication accompanied by high mortality rates. Yet, the molecular mechanisms initiating this disease remain poorly defined. In this study, we show that, after conditioning therapy, intestinal commensal bacteria and the damage-associated molecular pattern uric acid contribute to Nlrp3 inflammasome–mediated IL-1β production and that gastrointestinal decontamination and uric acid depletion reduced GvHD severity. Early blockade of IL-1β or genetic deficiency of the IL-1 receptor in dendritic cells (DCs) and T cells improved survival. The Nlrp3 inflammasome components Nlrp3 and Asc, which are required for pro–IL-1β cleavage, were critical for the full manifestation of GvHD. In transplanted mice, IL-1β originated from multiple intestinal cell compartments and exerted its effects on DCs and T cells, the latter being preferentially skewed toward Th17. Compatible with these mouse data, increased levels of active caspase-1 and IL-1β were found in circulating leukocytes and intestinal GvHD lesions of patients. Thus, the identification of a crucial role for the Nlrp3 inflammasome sheds new light on the pathogenesis of GvHD and opens a potential new avenue for the targeted therapy of this severe complication.

The current COVID-19 pandemic, caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has raised significant economic, social, and psychological concerns. The rapid spread of the virus, coupled with the absence of vaccines and antiviral treatments for SARS-CoV-2, has galvanized a major global endeavor to develop effective vaccines. Within a matter of just a few months of the initial outbreak, research teams worldwide, adopting a range of different strategies, embarked on a quest to develop effective vaccine that could be effectively used to suppress this virulent pathogen. In this review, we describe conventional approaches to vaccine development, including strategies employing proteins, peptides, and attenuated or inactivated pathogens in combination with adjuvants (including genetic adjuvants). We also present details of the novel strategies that were adopted by different research groups to successfully transfer recombinantly expressed antigens while using viral vectors (adenoviral and retroviral) and non-viral delivery systems, and how recently developed methods have been applied in order to produce vaccines that are based on mRNA, self-amplifying RNA (saRNA), and trans-amplifying RNA (taRNA). Moreover, we discuss the methods that are being used to enhance mRNA stability and protein production, the advantages and disadvantages of different methods, and the challenges that are encountered during the development of effective vaccines.

This review focuses on nano-structured delivery devices prepared from biodegradable and biocompatible natural and synthetic polymers, organic raw materials, metals, metal oxides, and their other compounds that culminated in the preparation of various nano-entities depending on the preparative techniques, and starting raw materials’ utilizations. Many nanoparticles (NPs) made of polymeric, metallic, magnetic, and non-magnetic origins, liposomes, hydrogels, dendrimers, and other carbon-based nano-entities have been produced. Developments in nanomaterial substrate and end products’ design, structural specifications, preparative strategies, chemo-biological interfacing to involve the biosystems interactions, surface functionalization, and on-site biomolecular and physiology-mediated target-specific delivery concepts, examples, and applications are outlined. The inherent toxicity, and safety of the design concepts in nanomaterial preparation, and their applications in biomedical fields, especially to the organs, cellular and sub-cellular deliveries are deliberated. Bioapplications, the therapeutic delivery modules’ pharmacokinetics and medicinal values, nanopharmaceutical designs, and their contributions as nano-entities in the healthcare biotechnology of drug delivery domains have also been discussed. The importance of site-specific triggers in nano-scale deliveries, the inherent and induced structural specifications of numerous nanomaterial entities belonging to NPs, nano-scale composites, nano-conjugates, and other nano-devices of organic and inorganic origins, near biological systems are detailed. Modifications that provide nano-deliveries of their intrinsic therapeutic actions, through structural and physicochemical characteristics modifications, and the proven success of various nano-delivery devices and currently available commercial nanomedicinal and nanopharmaceutical products are also provided.