Heat shock protein 90 inhibitor RGRN-305 potently attenuates skin inflammation

HSP90β shapes the fate of Th17 cells with the help of glycolysis-controlled methylation modification

BACKGROUND AND PURPOSE

Ulcerative colitis (UC) is a refractory inflammatory disease associated with immune dysregulation. Elevated levels of heat shock protein (HSP) 90 in the β but not α subtype were positively associated with disease status in UC patients. This study validated the possibility that pharmacological inhibition or reduction of HSP90β would alleviate colitis, induced by dextran sulfate sodium, in mice and elucidated its mechanisms.

EXPERIMENTAL APPROACH

Histopathological and biochemical analysis assessed disease severity, and bioinformatics and correlation analysis explained the association between the many immune cells and HSP90β. Flow cytometry was used to analyse the homeostasis and transdifferentiation of Th17 and Treg cells. In vitro inhibition and adoptive transfer assays were used to investigate functions of the phenotypically transformed Th17 cells. Metabolomic analysis, DNA methylation detection and chromatin immunoprecipitation were used to explore these mechanisms.

KEY RESULTS

The selective pharmacological inhibitor (HSP90βi) and shHSP90β significantly mitigated UC in mice and promoted transformation of Th17 to Treg cell phenotype, via Foxp3 transcription. The phenotypically-transformed Th17 cells by HSP90βi or shHSP90β were able to inhibit lymphocyte proliferation and colitis in mice. HSP90βi and shHSP90β selectively weakened glycolysis by stopping the direct association of HSP90β and GLUT1, the key glucose transporter, to accelerate ubiquitination degradation of GLUT1, and enhance the methylation of Foxp3 CNS2 region. Then, the mediator path was identified as the "lactate-STAT5-TET2" cascade.

CONCLUSION AND IMPLICATIONS

HSP90β shapes the fate of Th17 cells via glycolysis-controlled methylation modification to affect UC progression, which provides a new therapeutic target for UC.

Effect of Heat Shock Treatment on the Virulence of Grass Carp Reovirus in Rare Minnow Gobiocypris rarus

The mode and outcome of fish-virus interactions are influenced by many abiotic factors, among which water temperature is especially important in poikilothermic fish. Rare minnow Gobiocypris rarus is a eurythermal small cyprinid fish that is sensitive to infection with genotype II grass carp reovirus (GCRV). HSP70, a conservative and key player in heat shock response, is previously identified as an induced pro-viral factor during GCRV infection in vitro. Here, rare minnow was subjected to heat shock treatment (HST), 1 h treatment at 32 °C followed by reverting to a normal temperature of 24 °C, and subsequently challenged with GCRV-II at a dosage of 1 × LD50. The effect of HST on GCRV virulence in vivo was evaluated by calculating virus-associated mortality and viral load in both dead and survival fish. The results revealed that HST enhanced the mortality of rare minnow infected with GCRV; the fact that viral loads in the tissue samples of HST-treated fish were significantly higher than those in samples of the control group at 6, 8 d p.i. reflected a faster infection process due to HST. Quantitative gene expression analysis was further employed to show that the expression levels of Hsp70 in intestine and liver tissues from the HST group declined faster than muscle tissue after HST. HST W/O GCRV challenge upregulated proinflammatory cytokines such as MyD88 and Nf-κB, which was in consistence with the inflammation observed in histopathological analysis. This study shed light on the complexity of the interaction between fish abiotic and biotic stress response, which suggested that HST, an abiotic stress, could enhance the virulence of GCRV in Gobiocypris rarus that involved modulating the gene expression of host heat shock, as well as a pro-inflammatory response.

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.

New and Emerging Oral/Topical Small-Molecule Treatments for Psoriasis

The introduction of biologic therapies has led to dramatic improvements in the management of moderate-to-severe psoriasis. Even though the efficacy and safety of the newer biologic agents are difficult to match, oral administration is considered an important advantage by many patients. Current research is focused on the development of oral therapies with improved efficacy and safety compared with available alternatives, as exemplified by deucravacitinib, the first oral allosteric Tyk2 inhibitor approved for the treatment of moderate to severe psoriasis in adults. Recent advances in our knowledge of psoriasis pathogenesis have also led to the development of targeted topical molecules, mostly focused on intracellular signaling pathways such as AhR, PDE-4, and Jak-STAT. Tapinarof (an AhR modulator) and roflumilast (a PDE-4 inhibitor) have exhibited favorable efficacy and safety outcomes and have been approved by the FDA for the topical treatment of plaque psoriasis. This revision focuses on the most recent oral and topical therapies available for psoriasis, especially those that are currently under evaluation and development for the treatment of psoriasis.

Heat shock protein 90 inhibition attenuates inflammation in models of atopic dermatitis: a novel mechanism of action

Background

Heat shock protein 90 (HSP90) is an important chaperone supporting the function of many proinflammatory client proteins. Recent studies indicate HSP90 inhibition may be a novel mechanism of action for inflammatory skin diseases; however, this has not been explored in atopic dermatitis (AD).

Objectives

Our study aimed to investigate HSP90 as a novel target to treat AD.

Methods

Experimental models of AD were used including primary human keratinocytes stimulated with cytokines (TNF/IFNγ or TNF/IL-4) and a mouse model established by MC903 applications.

Results

In primary human keratinocytes using RT-qPCR, the HSP90 inhibitor RGRN-305 strongly suppressed the gene expression of Th1- (TNF, IL1B, IL6) and Th2-associated (CCL17, CCL22, TSLP) cytokines and chemokines related to AD. We next demonstrated that topical and oral RGRN-305 robustly suppressed MC903-induced AD-like inflammation in mice by reducing clinical signs of dermatitis (oedema and erythema) and immune cell infiltration into the skin (T cells, neutrophils, mast cells). Interestingly, topical RGRN-305 exhibited similar or slightly inferior efficacy but less weight loss compared with topical dexamethasone. Furthermore, RNA sequencing of skin biopsies revealed that RGRN-305 attenuated MC903-induced transcriptome alterations, suppressing genes implicated in inflammation including AD-associated cytokines (Il1b, Il4, Il6, Il13), which was confirmed by RT-qPCR. Lastly, we discovered using Western blot that RGRN-305 disrupted JAK-STAT signaling by suppressing the activity of STAT3 and STAT6 in primary human keratinocytes, which was consistent with enrichment analyses from the mouse model.

Conclusion

HSP90 inhibition by RGRN-305 robustly suppressed inflammation in experimental models mimicking AD, proving that HSP90 inhibition may be a novel mechanism of action in treating AD.

Efficacy and Safety of the Heat Shock Protein 90 Inhibitor RGRN-305 in Hidradenitis Suppurativa: A Parallel-Design Double-Blind Trial

Importance

Hidradenitis suppurativa is a painful immune-mediated disorder with limited treatment options; hence, a need exists for new treatments.

Objective

To evaluate the feasibility of heat shock protein 90 inhibition by RGRN-305 as a novel mechanism of action in treating moderate to severe hidradenitis suppurativa.

Design, Setting, and Participants

This was a parallel-design, double-blind, proof-of-concept, placebo-controlled randomized clinical trial conducted between September 22, 2021, and August 29, 2022, at the Department of Dermatology, Aarhus University Hospital in Denmark. The study included a 1- to 30-day screening period, a 16-week treatment period, and a 4-week follow-up period. Eligibility criteria included age 18 years or older and moderate to severe hidradenitis suppurativa with 6 or more inflammatory nodules or abscesses in at least 2 distinct anatomic regions. Of 19 patients screened, 15 patients were enrolled in the study. Intention-to-treat analysis was performed.

Interventions

Patients were randomly assigned (2:1) to receive oral RGRN-305, 250-mg tablet, or matching placebo once daily for 16 weeks.

Main Outcomes and Measures

The primary efficacy end point was the percentage of patients achieving Hidradenitis Suppurativa Clinical Response 50 (HiSCR-50) at week 16. Secondary efficacy end points included HiSCR-75 or HiSCR-90, Hidradenitis Suppurativa Physician's Global Assessment, Dermatology Life Quality Index scores, and a pain numeric rating scale. Safety was assessed by adverse events, physical examinations, clinical laboratory measurements, and electrocardiograms.

Results

A total of 15 patients were enrolled, completed the study, and were included in all analyses (10 [67%] female; median age, 29 [IQR, 23-41] years). The primary end point HiSCR-50 at week 16 was achieved by a higher percentage in the RGRN-305 group (60% [6 of 10]) than in the placebo group (20% [1 of 5]). Improvements were also observed across all secondary end points at week 16, including higher rates of the harder-to-reach HiSCR levels; 50% (5 of 10) achieved HiSCR-75 and 30% (3 of 10) achieved HiSCR-90, whereas none of the placebo-treated patients achieved HiSCR-75 or HiSCR-90. RGRN-305 was well tolerated, with no deaths or serious adverse events, and treatment-emergent adverse events were similarly frequent between the RGRN-305 and placebo groups.

Conclusions and Relevance

The findings of this trial suggest that heat shock protein 90 inhibition by RGRN-305 offers a novel mechanism of action in treating hidradenitis suppurativa, warranting further evaluation in larger trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT05286567.

Transcriptomic Analysis of Hidradenitis Suppurativa: A Unique Molecular Signature with Broad Immune Activation

Hidradenitis suppurativa is a chronic inflammatory skin disease with limited treatment options. The poorly understood pathogenesis hinders the development of effective treatments; therefore, a pressing need exists to further elucidate the molecular mechanisms in hidradenitis suppurativa. This study investigated the underlying inflammatory pathways and cell types in hidradenitis suppurativa using transcriptomic approaches with RNA sequencing of lesional and non-lesional skin biopsies from hidradenitis suppurativa, which was jointly analyzed with previously published transcriptomic data from atopic dermatitis and psoriasis patients. The differential expression and pathway enrichment analyses demonstrated the activation of multiple inflammatory processes, including the innate and adaptive immune systems, implicated in the hidradenitis suppurativa pathogenesis. In agreement, hidradenitis suppurativa exhibited a unique and heterogeneous cell type signature involving lymphoid and myeloid cells such as B cells and macrophages. Furthermore, hidradenitis suppurativa displayed increased expression of TH1/2/17 signatures with no predominant TH signatures unlike psoriasis (TH1/17) and atopic dermatitis (TH2). In summary, our study provides molecular insights into the pathomechanisms in hidradenitis suppurativa, revealing a strong and widespread immune activation, which may benefit from treatment strategies offering a broad immunomodulation of various key inflammatory pathways. Our data not only corroborate previously reported findings but also enhance our understanding of the immune dysregulation in hidradenitis suppurativa, uncovering novel and potential therapeutic targets.

Heat shock protein 90 (Hsp90) inhibitor STA-9090 (Ganetespib) ameliorates inflammation in a mouse model of atopic dermatitis

Molecular chaperones belonging to the heat shock protein 90 (Hsp90) family are implicated in inflammatory processes and described as potential novel therapeutic targets in autoimmune/inflammatory skin diseases. While the pathological role of circulating Hsp90 has been recently proposed in patients with atopic dermatitis (AD), a chronic inflammatory skin disease characterized by intense itching and recurrent skin lesions, studies aimed at investigating the role of Hsp90 as a potential target of AD therapy have not yet been conducted. Here, the effects of the Hsp90 blocker STA-9090 (Ganetespib) applied systemically or topically were determined in an experimental mouse model of dinitrochlorobenzene (DNCB)-induced AD. Intraperitoneal administration of STA-9090 ameliorated clinical disease severity, histological epidermal thickness, and dermal leukocyte infiltration in AD mice which was associated with reducing the scratching behavior in DNCB-treated animals. Additionally, topically applied STA-9090 led to lowered disease activity in AD mice, reduced serum levels of IgE, and up-regulated filaggrin expression in lesional skin samples. Our observations suggest that Hsp90 may be a promising therapeutic target in atopic dermatitis and potentially other inflammatory or autoimmune dermatoses.

HSPB8 up-regulation alleviates cognitive dysfunction in a mouse model of sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is associated with a higher risk of cognitive deficits; however, its potential mechanisms are still unknow. Recently, researches show that HSPB8, a family of small heat shock proteins, affects cognitive function and ameliorates sepsis-induced dysfunction. However, the role of HSPB8 in SAE-associated cognitive impairment has not been elucidated. In this study, we found that HSPB8 expression was up-regulated in the brain of mice with lipopolysaccharide-induced sepsis. HSPB8 overexpression alleviated cognitive decline in SAE mice. In addition, exogenous HSPB8 exerts neuroprotective effects and salvages synaptic function via regulating NRF1/TFAM-induced mitochondrial biogenesis and DRP1-mediate mitochondrial fission in a lipopolysaccharide-induced mouse model. Furthermore, HSPB8 overexpression inhibits IBA1 and NLRP3 activation in the SAE model. Overexpression of HSPB8 may be an efficient treatment for relieving SAE-related cognitive decline.

Psoriasis: a focus on upcoming oral formulations

INTRODUCTION

Targeted therapies have greatly improved the quality of life of patients with psoriasis. Despite the extensive list of treatments available, multiple new drugs are being developed, especially oral therapies with potential advantages as regards comfort of administration. However, the efficacy and safety of these new oral therapies need to be improved to match those of novel biologics.

AREAS COVERED

We provide a narrative review of the oral therapies for psoriasis that are currently under development, from Jak inhibitors to oral IL-17 and IL-23 inhibitors, among others. A literature search was performed for articles published from 1 January 2020, to 6 June 2023.

EXPERT OPINION

The approval of deucravacitinib, the first Jak inhibitor for the treatment of moderate-to-severe plaque psoriasis, heralds a bright therapeutic future with multiple new oral formulations. A great number of oral treatments with singular mechanism of action, like A3AR agonists, HSP90 inhibitors, ROCK-2 inhibitors, oral TNF inhibitors, oral IL-23 inhibitors, oral IL-17 inhibitors, PD4 inhibitors (orismilast) and several Tyk2 inhibitors, are currently being evaluated in clinical trials and could be suitable for approval in the future. Growing variation in treatment modes of administration will allow dermatologists to better integrate patient preferences in the therapeutic decision process.