A novel role of the scaffolding protein JLP in tuning CD40-induced activation of dendritic cells

The JNK-associated leucine zipper protein exerts a protective effect on renal parenchymal injury by limiting the inflammatory secretome in tubular cells

JNK-associated leucine zipper protein (JLP) is a newly identified renal endogenous anti-fibrotic factor that is selectively enriched in renal tubular epithelial cells (TECs). The loss of JLP by TECs is a landmark event that heralds the progression of kidney fibrosis. JLP deficiency ensues a series of pathogenetic cellular processes that are conducive to fibrotic injury. Inflammatory injury is functionally relevant in fibrotic kidneys, and TECs play an essential role in fueling inflammation through aberrant secretions. It is speculated that the loss of JLP in TECs is associated with the relentless inflammation during the development of kidney fibrosis. This study examined the alteration of a panel of inflammatory signatures in TECs under kidney fibrotic circumstances using a Jlp gene-modified unilateral ureteral obstruction (UUO) mouse model or cultured HK-2 cells. It was found that a deficiency of JLP in TECs led to a significant increase in the secretion of inflammatory cytokines including interleukin-1β (IL-1β), tumor necrosis factor (TNF-α), and monocyte chemotactic protein-1 (MCP-1), overactivation of the nuclear factor (NF)-κB/c-Jun N-terminal kinase (JNK) pathway, as well as nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis in response to pro-fibrotic damage. Additionally, the absence of JLP resulted in enhanced macrophage migration and fibroblast activation as paracrine effects elicited by injured TECs. In conclusion, the loss of JLP in TECs catalyses inflammatory injuries in the development of kidney fibrosis.

The Role of CD40 in Allergic Rhinitis and Airway Remodelling

Background

Allergic rhinitis (AR) affects millions of people and is lack of effective treatment. CD40 is an important costimulatory molecule in immunity. However, few studies have focused on the role of CD40 in AR.

Methods

In this study, we built mouse model of chronic AR. The mice were divided into the AR, control, intravenous CD40 siRNA, and nasal CD40 siRNA groups (n = 6 each). We detected OVA-sIgE, IL-4, IL-5, IL-13, IL-10, IFN-γ, and TGF-β levels in serum and supernatant by ELISA, CD40⁺ splenic DCs, and Foxp3⁺ Tregs by flow cytometry and CD40 mRNA by RT²-PCR. We also used PAS and MT stains to assess tissue remodelling.

Results

(1) The OVA-sIgE, IL-4, IL-5, and IL-13 levels in the serum or supernatant of nasal septal membrane of AR mice were significantly higher than control. After treated with CD40 siRNA, those indicators were significantly decreased. The IFN-γ, IL-10, and TGF-β levels in AR mice were significantly lower than that in control and were increased by administration of CD40 siRNA. (2) AR mice had significantly fewer Foxp3⁺ Tregs in the spleen than control mice. After treated with CD40 siRNA, AR mice had significantly more Foxp3⁺ Tregs. (3) AR mice exhibited a significantly higher CD40 mRNA levels than control. Administration of CD40 siRNA significantly reduced the CD40 mRNA level. (4) The AR mice showed significantly greater collagen deposition than the control in MT staining. Applications of CD40 siRNA significantly reduced the collagen deposition in AR mice.

Conclusion

CD40 siRNA therapy shows promise for chronic AR as it significantly attenuated allergic symptoms and Th2-related inflammation and upregulated Foxp3⁺ Tregs. CD40 plays a role in tissue remodelling in AR, which can be inhibited by CD40 siRNA application.

A negative feedback loop between JNK-associated leucine zipper protein and TGF-β1 regulates kidney fibrosis

Renal fibrosis is controlled by profibrotic and antifibrotic forces. Exploring anti-fibrosis factors and mechanisms is an attractive strategy to prevent organ failure. Here we identified the JNK-associated leucine zipper protein (JLP) as a potential endogenous antifibrotic factor. JLP, predominantly expressed in renal tubular epithelial cells (TECs) in normal human or mouse kidneys, was downregulated in fibrotic kidneys. Jlp deficiency resulted in more severe renal fibrosis in unilateral ureteral obstruction (UUO) mice, while renal fibrosis resistance was observed in TECs-specific transgenic Jlp mice. JLP executes its protective role in renal fibrosis via negatively regulating TGF-β1 expression and autophagy, and the profibrotic effects of ECM production, epithelial-to-mesenchymal transition (EMT), apoptosis and cell cycle arrest in TECs. We further found that TGF-β1 and FGF-2 could negatively regulate the expression of JLP. Our study suggests that JLP plays a central role in renal fibrosis via its negative crosstalk with the profibrotic factor, TGF-β1.

CAR T cell-induced cytokine release syndrome is mediated by macrophages and abated by IL-1 blockade

Chimeric antigen receptor (CAR) therapy targeting CD19 is an effective treatment for refractory B cell malignancies, especially acute lymphoblastic leukemia (ALL) ¹ . Although a majority of patients will achieve a complete response following a single infusion of CD19-targeted CAR-modified T cells (CD19 CAR T cells)^2-4, the broad applicability of this treatment is hampered by severe cytokine release syndrome (CRS), which is characterized by fever, hypotension and respiratory insufficiency associated with elevated serum cytokines, including interleukin-6 (IL-6)^2,5. CRS usually occurs within days of T cell infusion at the peak of CAR T cell expansion. In ALL, it is most frequent and more severe in patients with high tumor burden^2-4. CRS may respond to IL-6 receptor blockade but can require further treatment with high dose corticosteroids to curb potentially lethal severity^2-9. Improved therapeutic and preventive treatments require a better understanding of CRS physiopathology, which has so far remained elusive. Here we report a murine model of CRS that develops within 2-3 d of CAR T cell infusion and that is potentially lethal and responsive to IL-6 receptor blockade. We show that its severity is mediated not by CAR T cell-derived cytokines, but by IL-6, IL-1 and nitric oxide (NO) produced by recipient macrophages, which enables new therapeutic interventions.

Microfluidic-Based Live-Cell Analysis of NK Cell Migration In Vitro

Effector functions and cellular properties of natural killer (NK) cells are regulated by cellular and extracellular factors shaped by the microenvironments. NK cells express specific chemokine and non-chemokine receptors to aid preferential migrations or localizations in tissues. Good understanding of how NK-cell migratory properties are regulated in physiological and pathological microenvironments will provide further insights into the development of NK cell-based therapeutic approaches. In contrast to the commonly used conventional in vitro migration assays such as Trans-well assays that measure movements of a population of the migratory cells, microfluidic-based devices support live-cell imaging of cell migrations under a well-defined chemical gradient(s) at microscale. Subsequent analyses at single-cell level provide quantitative measurements of cell-migration parameters such as speed and Chemotactic Index, and permit distinguishing chemotaxis, chemokinesis, and chemo-repulsion. Our recent work established the use of a Y-shaped microfluidic device to study NK cell migrations in vitro. In this chapter, we described the detailed method of acquiring and analyzing NK cell migration in the microfluidic devices.

Scaffold protein JLP mediates TCR-initiated CD4+T cell activation and CD154 expression

CD4⁺ T-cell activation and its subsequent induction of CD154 (CD40 ligand, CD40L) expression are pivotal in shaping both the humoral and cellular immune responses. Scaffold protein JLP regulates signal transduction pathways and molecular trafficking inside cells, thus represents a critical component in maintaining cellular functions. Its role in regulating CD4⁺ T-cell activation and CD154 expression, however, is unclear. Here, we demonstrated expression of JLP in mouse tissues of lymph nodes, thymus, spleen, and also CD4⁺ T cells. Using CD4+ T cells from jlp-deficient and jlp-wild-type mice, we demonstrated that JLP-deficiency impaired T-cell proliferation, IL-2 production, and CD154 induction upon TCR stimulations, but had no impacts on the expression of other surface molecules such as CD25, CD69, and TCR. These observed impaired T-cell functions in the jlp-/- CD4⁺ T cells were associated with defective NF-AT activation and Ca²⁺ influx, but not the MAPK, NF-κB, as well as AP-1 signaling pathways. Our findings indicated that, for the first time, JLP plays a critical role in regulating CD4⁺ T cells response to TCR stimulation partly by mediating the activation of TCR-initiated Ca²⁺/NF-AT.

Scaffold protein JLP is critical for CD40 signaling in B lymphocytes

CD40 expression on the surface of B lymphocytes is essential for their biological function and fate decision. The engagement of CD40 with its cognate ligand, CD154, leads to a sequence of cellular events in B lymphocytes, including CD40 cytoplasmic translocation, a temporal and spatial organization of effector molecules, and a cascade of CD40-induced signal transduction. The JLP scaffold protein was expressed in murine B lymphocytes. Using B lymphocytes from jlp-deficient mice, we observed that JLP deficiency resulted in defective CD40 internalization upon CD154/CD40 engagement. Examination of interactions and co-localization among CD40, JLP, dynein, and Rab5 in B lymphocytes suggested that CD40 internalization is a process of JLP-mediated vesicle transportation that depends on Rab5 and dynein. JLP deficiency also diminished CD40-dependent activation of MAPK and JNK, but not NF-κB. Inhibiting vesicle transportation from the direction of cell periphery to the cell center by a dynein inhibitor (ciliobrevin D) impaired both CD154-induced CD40 internalization and CD40-dependent MAPK activities in B lymphocytes. Collectively, our data demonstrate a novel role of the JLP scaffold protein in the bridging of CD154-triggered CD40 internalization and CD40-dependent signaling in splenic B lymphocytes.

Proteomic analysis of the somatic and surface compartments from Dirofilaria immitis adult worms

Dirofilaria immitis (hearthworm) is a filarial roundworm transmitted by mosquitoes to different vertebrate hosts (dogs, cats and humans, among others), causing dirofilariosis. The adult worms reside in the pulmonary arteries affecting vessels and tissues and resulting in different pathological manifestations. Worms migrate to the heart and surrounding major vessels in heavy infections. Dirofilariosis can result in serious damage to affected hosts. In the last few years, a re-emergence of the disease driven by the climate change has been pointed out. Very recently, the knowledge at molecular level of this parasite has been extended by the published studies on its genome and transcriptome. Nevertheless, studies on the expression of defined protein sets in different parasite compartments and the corresponding role of those proteins in the host-parasite relationship have been relatively scarce to date. These include the description of the adult worm secretome, and some of the proteins eliciting humoural immune responses and those related with plasminogen binding in secreted and surface extracts of the parasite. Here, we investigate by proteomics the somatic and surface compartments of the D. immitis adult worm, adding new information on protein expression and localization that would facilitate a deeper understanding of the host-parasite relationships in dirofilariosis.