Sustained localized delivery of immunotherapy to lymph nodes reverses immunosuppression and increases long-term survival in murine glioblastoma

Development of a Composite Hydrogel Containing Statistically Optimized PDGF-Loaded Polymeric Nanospheres for Skin Regeneration: In Vitro Evaluation and Stem Cell Differentiation Studies

Platelet-derived growth factor-BB (PDGF-BB) is a polypeptide growth factor generated by platelet granules faced to cytokines. It plays a role in forming and remodeling various tissue types, including epithelial tissue, through interaction with cell-surface receptors on most mesenchymal origin cells. However, it breaks down quickly in biological fluids, emphasizing the importance of preserving them from biodegradation. To address this challenge, we formulated and evaluated PDGF-encapsulated nanospheres (PD@PCEC) using polycaprolactone-polyethylene glycol-polycaprolactone. PD@PCECs were fabricated through the triple emulsion methodology and optimized by using the Box-Behnken design. The encapsulation efficiency (EE) of nanoencapsulated PDGF-BB was investigated concerning four variables: stirring rate (X1), stirring duration (X2), poly(vinyl alcohol) concentration (X3), and PDGF-BB concentration (X4). The selected optimized nanospheres were integrated into a gelatin-collagen scaffold (PD@PCEC@GC) and assessed for morphology, biocompatibility, in vitro release, and differentiation-inducing activity in human adipose-derived stem cells (hADSCs). The optimized PD@PCEC nanospheres exhibited a particle size of 177.9 ± 91 nm, a zeta potential of 5.2 mV, and an EE of 87.7 ± 0.44%. The release profile demonstrated approximately 85% of loaded PDGF-BB released during the first 360 h, with a sustained release over the entire 504 h period, maintaining bioactivity of 87.3%. The study also included an evaluation of the physicochemical properties of the scaffolds and an assessment of hADSC adhesion to the scaffold's surface. Additionally, hADSCs cultivated within the scaffold effectively differentiated into keratinocyte-like cells (KLCs) over 21 days, evidenced by morphological changes and upregulation of keratinocyte-specific genes, including cytokeratin 18, cytokeratin 19, and involucrin, at both transcriptional and protein levels.

Novel technologies for applying immune checkpoint blockers

Cancer cells develop several ways to subdue the immune system among others via upregulation of inhibitory immune checkpoint (ICP) proteins. These ICPs paralyze immune effector cells and thereby enable unfettered tumor growth. Monoclonal antibodies (mAbs) that block ICPs can prevent immune exhaustion. Due to their outstanding effects, mAbs revolutionized the field of cancer immunotherapy. However, current ICP therapy regimens suffer from issues related to systemic administration of mAbs, including the onset of immune related adverse events, poor pharmacokinetics, limited tumor accessibility and immunogenicity. These drawbacks and new insights on spatiality prompted the exploration of novel administration routes for mAbs for instance peritumoral delivery. Moreover, novel ICP drug classes that are adept to novel delivery technologies were developed to circumvent the drawbacks of mAbs. We therefore review the state-of-the-art and novel delivery strategies of ICP drugs.

PA-X Protein of H1N1 Subtype Influenza Virus Disables the Nasal Mucosal Dendritic Cells for Strengthening Virulence

PA-X protein arises from a ribosomal frameshift in the PA of influenza A virus (IAV). However, the immune regulatory effect of the PA-X protein of H1N1 viruses on the nasal mucosal system remains unclear. Here, a PA-X deficient H1N1 rPR8 viral strain (rPR8-△PAX) was generated and its pathogenicity was determined. The results showed that PA-X was a pro-virulence factor in mice. Furthermore, it reduced the ability of H1N1 viruses to infect dendritic cells (DCs), the regulator of the mucosal immune system, but not non-immune cells (DF-1 and Calu-3). Following intranasal infection of mice, CCL20, a chemokine that monitors the recruitment of submucosal DCs, was downregulated by PA-X, resulting in an inhibition of the recruitment of CD11b+ DCs to submucosa. It also attenuated the migration of CCR7+ DCs to cervical lymph nodes and inhibited DC maturation with low MHC II and CD40 expression. Moreover, PA-X suppressed the maturation of phenotypic markers (CD80, CD86, CD40, and MHC II) and the levels of secreted pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) while enhancing endocytosis and levels of anti-inflammatory IL-10 in vitro, suggesting an impaired maturation of DCs that the key step for the activation of downstream immune responses. These findings suggested the PA-X protein played a critical role in escaping the immune response of nasal mucosal DCs for increasing the virulence of H1N1 viruses.

PA-X protein assists H9N2 subtype avian influenza virus in escaping immune response of mucosal dendritic cells

H9N2 subtype low pathogenicity avian influenza virus (AIV) poses a potential zoonotic risk. PA-X, a novel protein generated by PA gene ribosomal frameshift, is considered to be the virulence factor of H9N2 subtype AIVs. Our study found that rTX possessing PA-X protein enhanced the mammalian pathogenicity of H9N2 subtype AIVs compared with PA-X-deficient virus (rTX-FS). Furthermore, PA-X protein inhibited H9N2 subtype AIVs to infect dendritic cells (DCs), but not nonimmune cells (MDCK cells). Meanwhile, PA-X protein suppressed the phenotypic expression (CD80, CD86, CD40 and MHCII), early activation marker (CD69) and pro-inflammatory cytokines (IL-6 and TNF-α), whereas increased anti-inflammatory cytokine (IL-10) in DCs. After intranasally viral infection in mice, we found that PA-X protein of H9N2 subtype AIVs reduced CD11b+ and CD103+ subtype mucosal DCs recruitment to the nasal submucosa by inhibiting CCL20 expression. Moreover, PA-X protein abolished the migratory ability of CD11b+ and CD103+ DCs into draining cervical lymph nodes by down-regulating CCR7 expression. The rTX-infected DCs significantly impaired the allogeneic CD4+ T cell proliferation, suggesting PA-X protein suppressed the immune functions of DCs for hindering the downstream immune activation. These findings indicated that PA-X protein assisted H9N2 subtype AIVs in escaping immune response of mucosal DCs for enhancing the pathogenicity.

Immunology Meets Bioengineering: Improving the Effectiveness of Glioblastoma Immunotherapy

Glioblastoma (GBM) therapy has seen little change over the past two decades. Surgical excision followed by radiation and chemotherapy is the current gold standard treatment. Immunotherapy techniques have recently transformed many cancer treatments, and GBM is now at the forefront of immunotherapy research. GBM immunotherapy prospects are reviewed here, with an emphasis on immune checkpoint inhibitors and oncolytic viruses. Various forms of nanomaterials to enhance immunotherapy effectiveness are also discussed. For GBM treatment and immunotherapy, we outline the specific properties of nanomaterials. In addition, we provide a short overview of several 3D (bio)printing techniques and their applications in stimulating the GBM microenvironment. Lastly, the susceptibility of GBM cancer cells to the various immunotherapy methods will be addressed.

Cryogel vaccines effectively induce immune responses independent of proximity to the draining lymph nodes

The delivery location of traditional vaccines can impact immune responses and resulting efficacy. Cryogel-based cancer vaccines, which are typically injected near the inguinal lymph nodes (iLNs), recruit and activate dendritic cells (DC) in situ, induce DC homing to the iLNs, and have generated potent anti-tumor immunity against several murine cancer models. However, whether cryogel vaccination distance to a draining LN affects the kinetics of DC homing and downstream antigen-specific immunity is unknown, given the heightened importance of the scaffold vaccine site. We hypothesized that vaccination near the iLNs would lead to more rapid DC trafficking to the iLNs, thereby inducing faster and stronger immune responses. Here, mice were injected with cryogel vaccines against ovalbumin either adjacent or distal to the iLNs, and the resultant DC trafficking kinetics, T cell phenotypes, antigen-specific T cell and humoral responses, and prophylactic efficacy in an ovalbumin-expressing tumor model were assessed. Cryogel vaccines induced potent, long-lasting antigen-specific immune responses independent of distance to the iLNs, with no significant differences in DC trafficking kinetics, ovalbumin-specific T cell and antibody responses, or prophylactic efficacy. Moreover, DC trafficking and activation state were not impacted when cryogels were injected near a tumor. These results demonstrate a flexibility in vaccination location for scaffold-based vaccines, independent of draining LN distance.