The nucleic acid scavenger polyamidoamine third-generation dendrimer inhibits fibroblast activation and granulation tissue contraction

Synthetic polypeptides inhibit nucleic acid-induced inflammation in autoimmune diseases by disrupting multivalent TLR9 binding to LL37-DNA bundles

Complexes of extracellular nucleic acids (NAs) with endogenous proteins or peptides, such as LL37, break immune balance and cause autoimmune diseases, whereas NAs with arginine-enriched peptides do not. Inspired by this, we synthesize a polyarginine nanoparticle PEG-TK-NPArg, which effectively inhibits Toll-like receptor-9 (TLR9) activation, in contrast to LL37. To explore the discrepancy effect of PEG-TK-NPArg and LL37, we evaluate the periodic structure of PEG-TK-NPArg-NA and LL37-NA complexes using small-angle X-ray scattering. LL37-NA complexes have a larger inter-NA spacing that accommodates TLR9, while the inter-NA spacing in PEG-TK-NPArg-NA complexes mismatches with the cavity of TLR9, thus inhibiting an interaction with multiple TLR9s, limiting their clustering and damping immune induction. Subsequently, the inhibitory inflammation effect of PEG-TK-NPArg is proved in an animal model of rheumatoid arthritis. This work on how the scavenger-NA complexes inhibit the immune response may facilitate proof-of-concept research translating to clinical application.

Could hyperbaric oxygen be an effective therapy option for pathological scars? A systematic review and meta-analysis

BACKGROUND

Hyperbaric oxygen (HBO) therapy involves breathing pure oxygen or a high oxygen concentration above atmospheric (ATM) pressure in an enclosed chamber. Studies on pathological scars have demonstrated that HBO can inhibit the formation of pathological scars.

OBJECTIVE

To evaluate the efficacy of HBO in the treatment of pathological scars via meta-analysis.

METHODS

Searches were run on various databases, including the Cochrane, Embase, PubMed, Web of Science, and CNKI databases. A comparative study was conducted on patients with pathological scars treated with or without HBO. We used RevMan 5.4 software to determine the recurrence rate, treatment satisfaction, and Vancouver Scar Scale(VSS) score in the pathological scar.

RESULTS

A total of 543 publications were identified; after screening, four were selected for review, including one randomized controlled trial (RCT), one controlled clinical trial (CCT), and two retrospective cohort studies. Meta-analysis results showed that HBO treatment reduced the pathological scar recurrence rate after surgery and radiotherapy (OR = 0.26, 95% CI: 0.13-0.52, p = 0.0001). Patients had higher satisfaction after HBO therapy (OR = 4.45, 95% CI: 1.49-13.30, p = 0.007). The Vancouver scar scale (VSS) score of patients with pathological scars was significantly improved in the HBO group (SMD: -3.82, 95% CI: -6.07to -0.49, p = 0.02).

CONCLUSIONS

HBO treatment decreased the recurrence rate of pathological scars after surgery and radiotherapy, increased patient satisfaction, and reduced the VSS score, thus providing a new way to treat pathological scar hyperplasia. However, evaluation of the longer-term effects of HBO treatment requires further comprehensive studies, including more RCTs.

Mixed-surface polyamidoamine polymer variants retain nucleic acid-scavenger ability with reduced toxicity

Nucleic acid-binding polymers can have anti-inflammatory properties and beneficial effects in animal models of infection, trauma, cancer, and autoimmunity. PAMAM G3, a polyamidoamine dendrimer, is fully cationic bearing 32 protonable surface amines. However, while PAMAM G3 treatment leads to improved outcomes for mice infected with influenza, at risk of cancer metastasis, or genetically prone to lupus, its administration can lead to serosal inflammation and elevation of biomarkers of liver and kidney damage. Variants with reduced density of cationic charge through the interspersal of hydroxyl groups were evaluated as potentially better-tolerated alternatives. Notably, the variant PAMAM G3 50:50, similar in size as PAMAM G3 but with half the charge, was not toxic in cell culture, less associated with weight loss or serosal inflammation after parenteral administration, and remained effective in reducing glomerulonephritis in lupus-prone mice. Identification of such modified scavengers should facilitate their development as safe and effective anti-inflammatory agents.

Targeting DAMPs with nucleic acid scavengers to treat lupus

Systemic lupus erythematosus (SLE) is a chronic and often progressive autoimmune disorder marked clinically by a variable constellation of symptoms including fatigue, rash, joint pains, and kidney damage. The lungs, heart, gastrointestinal system, and brain can also be impacted, and individuals with lupus are at higher risk for atherosclerosis, thrombosis, thyroid disease, and other disorders associated with chronic inflammation . Autoimmune diseases are marked by erroneous immune responses in which the target of the immune response is a "self"-antigen, or autoantigen, driven by the development of antigen-specific B or T cells that have overcome the normal systems of self-tolerance built into the development of B and T cells. SLE is specifically characterized by the production of autoantibodies against nucleic acids and their binding proteins, including anti-double stranded DNA, anti-Smith (an RNA binding protein), and many others . These antibodies bind their nuclear-derived antigens to form immune complexes that cause injury and scarring through direct deposition in tissues and activation of innate immune cells . In over 50% of SLE patients, immune complex aggregation in the kidneys drives intrarenal inflammation and injury and leads to lupus nephritis, a progressive destruction of the glomeruli that is one of the most common causes of lupus-related death . To counter this pathology increasing attention has turned to developing approaches to reduce the development and continued generation of such autoantibodies. In particular, the molecular and cellular events that lead to long term, continuous activation of such autoimmune responses have become the focus of new therapeutic strategies to limit renal and other pathologies in lupus patients. The focus of this review is to consider how the innate immune system is involved in the development and progression of lupus nephritis and how a novel approach to inhibit innate immune activation by neutralizing the activators of this response, called Damage Associated Molecular Patterns, may represent a promising approach to treat this and other autoimmune disorders.

DAMPs/PAMPs induce monocytic TLR activation and tolerance in COVID-19 patients; nucleic acid binding scavengers can counteract such TLR agonists

Millions of COVID-19 patients have succumbed to respiratory and systemic inflammation. Hyperstimulation of toll-like receptor (TLR) signaling is a key driver of immunopathology following infection by viruses. We found that severely ill COVID-19 patients in the Intensive Care Unit (ICU) display hallmarks of such hyper-stimulation with abundant agonists of nucleic acid-sensing TLRs present in their blood and lungs. These nucleic acid-containing Damage and Pathogen Associated Molecular Patterns (DAMPs/PAMPs) can be depleted using nucleic acid-binding microfibers to limit the patient samples' ability to hyperactivate such innate immune receptors. Single-cell RNA-sequencing revealed that CD16+ monocytes from deceased but not recovered ICU patients exhibit a TLR-tolerant phenotype and a deficient anti-viral response after ex vivo TLR stimulation. Plasma proteomics confirmed such myeloid hyperactivation and revealed DAMP/PAMP carrier consumption in deceased patients. Treatment of these COVID-19 patient samples with MnO nanoparticles effectively neutralizes TLR activation by the abundant nucleic acid-containing DAMPs/PAMPs present in their lungs and blood. Finally, MnO nanoscavenger treatment limits the ability of DAMPs/PAMPs to induce TLR tolerance in monocytes. Thus, treatment with microfiber- or nanoparticle-based DAMP/PAMP scavengers may prove useful for limiting SARS-CoV-2 induced hyperinflammation, preventing monocytic TLR tolerance, and improving outcomes in severely ill COVID-19 patients.

Design of therapeutic biomaterials to control inflammation

Inflammation plays an important role in the response to danger signals arising from damage to our body and in restoring homeostasis. Dysregulated inflammatory responses occur in many diseases, including cancer, sepsis and autoimmunity. The efficacy of anti-inflammatory drugs, developed for the treatment of dysregulated inflammation, can be potentiated using biomaterials, by improving the bioavailability of drugs and by reducing side effects. In this Review, we first outline key elements and stages of the inflammatory environment and then discuss the design of biomaterials for different anti-inflammatory therapeutic strategies. Biomaterials can be engineered to scavenge danger signals, such as reactive oxygen and nitrogen species and cell-free DNA, in the early stages of inflammation. Materials can also be designed to prevent adhesive interactions of leukocytes and endothelial cells that initiate inflammatory responses. Furthermore, nanoscale platforms can deliver anti-inflammatory agents to inflammation sites. We conclude by discussing the challenges and opportunities for biomaterial innovations in addressing inflammation.

Breast cancer-derived DAMPs enhance cell invasion and metastasis, while nucleic acid scavengers mitigate these effects

Breast cancer (BC) is the most common malignancy in women. Particular subtypes with aggressive behavior are major contributors to poor outcomes. Triple-negative breast cancer (TNBC) is difficult to treat, pro-inflammatory, and highly metastatic. We demonstrate that TNBC cells express TLR9 and are responsive to TLR9 ligands, and treatment of TNBC cells with chemotherapy increases the release of nucleic-acid-containing damage-associated molecular patterns (NA DAMPs) in cell culture. Such culture-derived and breast cancer patient-derived NA DAMPs increase TLR9 activation and TNBC cell invasion in vitro. Notably, treatment with the polyamidoamine dendrimer generation 3.0 (PAMAM-G3) behaved as a nucleic acid scavenger (NAS) and significantly mitigates such effects. In mice that develop spontaneous BC induced by polyoma middle T oncoprotein (MMTV-PyMT), treatment with PAMAM-G3 significantly reduces lung metastasis. Thus, NAS treatment mitigates cancer-induced inflammation and metastasis and represents a novel therapeutic approach for combating breast cancer.

Nanotechnology for Pain Management: Current and Future Therapeutic Interventions

Pain is one of the most common medical conditions and affects more Americans than diabetes, heart disease, and cancer combined. Current pain treatments mainly rely on opioid analgesics and remain unsatisfactory. The life-threatening side effects and addictive properties of opioids demand new therapeutic approaches. Nanomedicine may be able to address these challenges as it allows for sensitive and targeted treatments without some of the burdens associated with current clinical pain therapies. This review discusses the physiology of pain, the current landscape of pain treatment, novel targets for pain treatment, and recent and ongoing efforts to effectively treat pain using nanotechnology-based approaches. We highl ight advances in nanoparticle-based drug delivery to reduce side effects, gene therapy to tackle the source of pain, and nanomaterials-based scavenging to proactively mediate pain signaling.

Metabolic memory of dietary restriction ameliorates DNA damage and adipocyte size in mouse visceral adipose tissue

Dietary restriction (DR) is thought to exert its beneficial effects on healthspan at least partially by a senolytic and senostatic action, i.e. by reducing frequencies of cells with markers of DNA damage and senescence in multiple tissues. Due to its importance in metabolic and inflammation regulation, fat is a prime tissue for health span determination as well as a prime target for DR. We aimed to determine here whether the beneficial effects of DR would be retained over a subsequent period of ad libitum (AL) feeding. Male mice were kept under either 40% DR or AL feeding regimes from 3 to 12 months of age and then either switched back to the opposite feeding regimen or kept in the same state for another 3 months. Visceral adipose tissue from 4 to 5 mice per group for all conditions was analysed for markers of senescence (adipocyte size, γH2A.X, p16, p21) and inflammation (e.g. IL-6, TNFα, IL-1β) using immuno-staining or qPCR. Macrophages were detected by immunohistochemistry. We found that both 9 and 12 months DR (long term) as well as 3 month (short term, mid-life onset) DR reduced the number of cells harbouring DNA damage and adipocyte size (area and perimeter) in visceral adipocytes with similar efficiency. Importantly, beneficial health markers induced by DR such as small adipocyte size and low DNA damage were maintained for at least 3 month after termination of DR, demonstrating that the previously identified 'metabolic memory' of the DR state in male mice extends to senescence markers in visceral fat.

Dietary Restriction Ameliorates Age-Related Increase in DNA Damage, Senescence and Inflammation in Mouse Adipose Tissuey

Ageing is associated with redistribution of fat around the body and saturation of visceral adipose depots. Likewise, the presence of excess fat in obesity or during ageing places extra stress on visceral depots, resulting in chronic inflammation and increased senescence. This process can contribute to the establishment of the metabolic syndrome and accelerated ageing. Dietary restriction (DR) is known to alleviate physiological signs of inflammation, ageing and senescence in various tissues including adipose tissue.

OBJECTIVES

Our pilot study aimed to analyse senescence and inflammation parameters in mouse visceral fat tissue during ageing and by short term, late-onset dietary restriction as a nutritional intervention. Design, measurements: In this study we used visceral adipose tissue from mice between 5 and 30 months of age and analysed markers of senescence (adipocyte size, γH2A.X, p16, p21) and inflammation (e.g. IL-6, TNFα, IL-1β, macrophage infiltration) using immuno-staining, as well as qPCR for gene expression analysis. Fat tissues from 3 mice per group were analysed.

RESULTS

We found that the amount of γH2A.X foci as well as the expression of senescence and inflammation markers increased during ageing but decreased with short term DR. In contrast, the increase in amounts of single or aggregated macrophages in fat depots occurred only at higher ages. Surprisingly, we also found that adipocyte size as well as some senescence parameters decreased at very high age (30 months).

CONCLUSIONS

Our results demonstrate increased senescence and inflammation during ageing in mouse visceral fat while DR was able to ameliorate several of these parameters as well as increased adipocyte size at 17.5 months of age. This highlights the health benefits of a decreased nutritional intake over a relatively short period of time at middle age.

Toll Like Receptors in systemic sclerosis: An emerging target

Pattern Recognition Receptors are critical receptors that elicit an immune response upon their activation that culminates in activation of NF-KB and cytokine secretion. Key among these receptors are the Toll-Like Receptors (TLRs). These evolutionary conserved receptors form a key part in the defence against various pathogens and comprise a key part of the innate immune system. Systemic sclerosis is an autoimmune disease in which a breach of tolerance has occurred and leads to fulminant autoimmunity, dysregulated cytokines, pro-fibrotic mediators and activation of fibroblasts leading to fibrosis via collagen deposition. It has become apparent in recent years that the innate immune system and specifically TLRs are important in disease pathogenesis; responding to internal ligands to initiate an innate immune response ultimately leading to release of a variety of factors that initiate and perpetuate fibrosis. This review will examine the recent evidence of TLR signalling in systemic sclerosis and the internal danger associated molecules that may mediate the fibrotic cascade. Evaluation of their contribution to disease in systemic sclerosis and possible therapeutic targeting will be discussed.

Polymeric drugs: Advances in the development of pharmacologically active polymers

Synthetic polymers play a critical role in pharmaceutical discovery and development. Current research and applications of pharmaceutical polymers are mainly focused on their functions as excipients and inert carriers of other pharmacologically active agents. This review article surveys recent advances in alternative pharmaceutical use of polymers as pharmacologically active agents known as polymeric drugs. Emphasis is placed on the benefits of polymeric drugs that are associated with their macromolecular character and their ability to explore biologically relevant multivalency processes. We discuss the main therapeutic uses of polymeric drugs as sequestrants, antimicrobials, antivirals, and anticancer and anti-inflammatory agents.