Expression and purification of recombinant human Mig in Escherichia coli and its comparison with murine Mig

Pt-Te-Nanorod-Based Photothermal Chemokine Immunotherapy for All Stages of Cancer via Adaptive and Innate Immunity

The chemokine (C-X-C) motif ligand 9 (CXCL9) is one of the lymphocyte-traffic-involved chemokines. Despite the immunotherapeutic potential of CXCL9 for recruiting effector T cells (cluster of differentiation 4+ (CD4+) and CD8+ T cells) and natural killer cells (NK cells) around the tumors, practical applications of CXCL9 have been limited because of its immune toxicity and lack of stability in vivo. To overcome these limitations, we designed and synthesized Pt-Te nanorods (PtTeNRs), which exhibited excellent photothermal conversion efficiency with stable CXCL9 payload characteristics under the physiological conditions of in vivo environments. We developed a CXCL9-based immunotherapy strategy by utilizing the unique physicochemical properties of developed PtTeNRs. The investigation revealed that the PtTeNR-loaded CXCL9 was effectively accumulated in the tumor, subsequently released in a sustained manner, and successfully recruited effector T cells for immunotherapy of the designated tumor tissue. In addition, a synergistic effect was observed between the photothermal (PT) therapy and antiprogrammed cell death protein 1 (aPD-1) antibody. In this study, we demonstrated that PtTeNR-based CXCL9, PT, and aPD-1 antibody trimodal therapy delivers an outstanding tumor suppression effect in all stages of cancer, including phases 1-4 and tumor recurrence.

Intranasal delivery of an adenovirus-vector vaccine co-expressing a modified spike protein and a genetic adjuvant confers lasting mucosal immunity against SARS-CoV-2

The ongoing COVID-19 pandemic caused by SARS-CoV-2 infection has threatened global health. Since the first case of infection was reported in December 2019, SARS-CoV-2 has rapidly spread worldwide and caused millions of deaths. As vaccination is the best way to protect the host from invading pathogens, several vaccines have been developed to prevent the infection of SARS-CoV-2, saving numerous lives thus far. However, SARS-CoV-2 constantly changes its antigens, resulting in escape from vaccine-induced protection, and the longevity of immunity induced by vaccines remains an issue. Additionally, traditional intramuscular COVID-19 vaccines are insufficient at evoking mucosal-specific immune responses. Because the respiratory tract is the primary route of SARS-CoV-2 entry, the need for mucosal vaccines is strong. Using an adenoviral (Ad) vector platform, we generated Ad5-S.Mod, a recombinant COVID-19 vaccine that encodes modified-spike (S) antigen and the genetic adjuvant human CXCL9. Intranasal delivery of Ad5-S.Mod elicited superior airway humoral and T-cell responses over traditional intramuscular vaccines and protected mice from lethal SARS-CoV-2 infection. cDC1 cells were required for the generation of antigen-specific CD8⁺ T-cell responses and CD8⁺ tissue-resident memory T-cell development in intranasal Ad5-S.Mod vaccinated mice. Furthermore, we confirmed the efficacy of the intranasal Ad5-S.Mod vaccine in terms of transcriptional changes and identified lung macrophages as a key supporter of maintenance of lung-resident memory T and B cells. Our study demonstrates Ad5-S.Mod has the potential to confer protective immunity against SARS-CoV-2 and that lung macrophages support the maintenance of vaccine-induced tissue-resident memory lymphocytes.

Characterization and Antimicrobial Activity of the Teleost Chemokine CXCL20b

Fish are a potential source of diverse organic compounds with a broad spectrum of biological activities. Many fish-derived antimicrobial peptides and proteins are key components of the fish innate immune system. They are also potential candidates for development of new antimicrobial agents. CXCL20b is a grass carp (Ctenopharyngodon idella) CXC chemokine strongly transcribed at the early stage of bacterial infections, for which the immune role had not been reported to date. In the present study, we found that CXCL20b is a cationic amphipathic protein that displays potent antimicrobial activity against both Gram-positive and Gram-negative bacteria. The results of DiOC₂(3) and atomic force microscopy (AFM) assays indicated that CXCL20b could induce bacterial membrane depolarization and disruption in a short time. By performing further structure-activity studies, we found that the antimicrobial activity of CXCL20b was mainly relative to the N-terminal random coil region. The central part of this cytokine representing β-sheet region was insoluble in water and the C-terminal α-helical region did not show an antimicrobial effect. The results presented in this article support the poorly understood function of CXCL20b, which fulfills an important role in bony fish antimicrobial immunity.

Molecular dynamics based improvement of the solubilizing self-cleavable tag Zbasic-ΔI-CM application in the preparation of recombinant proteins in Escherichia coli

Z_basic-ΔI-CM is a novel intein-based self-cleavable tag we developed to accelerate the soluble expression of recombinant proteins in Escherichia coli (E. coli). Previously we found that intein activity could be interfered by its flanking exteins, and thus reducing the production efficiency and final yield. In this work, we used CXC-chemokine 9 (CXCL9) as a model C-extein, which fusion with Z_basic-ΔI-CM showed high intein activity. When the fusion protein got soluble expression, CXCL9 was released immediately and purified directly from cell lysis supernatant. The results demonstrated that Z_basic-ΔI-CM tag had successfully mediated the efficient production of high-quality CXCL9 with reduced time and resources consumption in comparison with inclusion bodies expression. Molecular dynamics simulations suggested that the improved cleavage activity of Z_basic-ΔI-CM upon fusion with CXCL9 may be due to the higher dynamics of the first half loop and stabilization of the second half loop of intein. Our results proved that the self-cleavable Z_basic-ΔI-CM mediated soluble expression could be a feasible process for cytokines like CXCL9, thus of attractive potentials for production of therapeutic proteins using E. coli expression system.

Development of a recombinant human IL-15·sIL-15Rα/Fc superagonist with improved half-life and its antitumor activity alone or in combination with PD-1 blockade in mouse model

Recombinant human interleukin-15 (IL-15) is a potent cancer immunotherapeutic candidate due to its excellent immune stimulating effects. Previous work demonstrated that IL-15 appeared with short half-life in circulation system, while the complex with its receptor can prolong the half-life as well as benefit its activities in vivo. Therefore, IL-15 complex was more favorably considered for clinical development. Herein we developed IL-15·sIL-15Rα/Fc, a complex comprising of IL-15 and the extracellular region of its receptor alpha subunit which fused to Immunoglobulin G (IgG1) Fc to further prolong the half-life in plasma. Through transient gene expression in HEK293 cells, we expressed the superagonist by co-transfection of plasmids encoding IL-15 and sIL-15Rα/Fc respectively, yielding 36 mg/L of product after purification. Pharmacokinetic study demonstrated that the combination profoundly prolonged the half-life of IL-15 to 13.1 h in mice, about 18 folds longer than that of IL-15 monomer which is around 0.7 h. The bioactivity of the superagonist was characterized by CTLL-2 cells proliferation assay in vitro, showing its capability of stimulating the expansion of memory CD8⁺ T cells (cluster of differentiation) in mouse spleen. Using a HT-29 xenograft NOD-SCID mouse model, we observed tumor growth inhibition in all groups that received the superagonist, indicating its anti-tumor efficacy via stimulating infused human immune cells. In addition, combo cancer treatment by IL-15·sIL-15Rα/Fc and programmed death-1 (PD-1) antibody have shown stronger inhibitory effects as compared with treatment with either single molecule. Therefore, we developed IL-15·sIL-15Rα/Fc to be a long half-life potential cancer immunotherapy candidate that can be applied alone or in synergy with PD-1/PD-L1 blockade.

Purification of inclusion bodies using PEG precipitation under denaturing conditions to produce recombinant therapeutic proteins from Escherichia coli

It has been documented that the purification of inclusion bodies from Escherichia coli by size exclusion chromatography (SEC) may benefit subsequent refolding and recovery of recombinant proteins. However, loading volume and the high cost of the column limits its application in large-scale manufacturing of biopharmaceutical proteins. We report a novel process using polyethylene glycol (PEG) precipitation under denaturing conditions to replace SEC for rapid purification of inclusion bodies containing recombinant therapeutic proteins. Using recombinant human interleukin 15 (rhIL-15) as an example, inclusion bodies of rhIL-15 were solubilized in 7 M guanidine hydrochloride, and rhIL-15 was precipitated by the addition of PEG 6000. A final concentration of 5% (w/v) PEG 6000 was found to be optimal to precipitate target proteins and enhance recovery and purity. Compared to the previously reported S-200 size exclusion purification method, PEG precipitation was easier to scale up and achieved the same protein yields and quality of the product. PEG precipitation also reduced manufacturing time by about 50 and 95% of material costs. After refolding and further purification, the rhIL-15 product was highly pure and demonstrated a comparable bioactivity with a rhIL-15 reference standard. Our studies demonstrated that PEG precipitation of inclusion bodies under denaturing conditions holds significant potential as a manufacturing process for biopharmaceuticals from E. coli protein expression systems.

Eukaryotic Expression and Purification of Native Form of Mouse Midkine from Pichia pastoris

To confirm the treating effectiveness of midkine as an articular protective agent, mouse midkine (mMK) was produced for the pre-clinic long-term studies in mice. The protein was expressed under the control of the AOX1 gene promoter in Pichia pastoris, X-33 strain, and secreted into fermentation broth through high-density fermentation. Approximately 380 mg mMK, containing authentic and truncated forms, was secreted into 1 liter induction medium and 280 mg mMK was obtained after one-step purification on a 50 ml SP Sepharose Fast Flow column. The purified protein was characterized and identified to be the mature, authentic form of mMK. N-terminal five amino acid sequence was determined to be K-K-K-E-K. SDS-PAGE analysis indicated that the molecular weight of the product was about 13 KDa. The purity of the purified rmMK protein was determined to be 99% by high performance liquid chromatography. The biological activity of final product was verified via migration assay on osteoblast-like UMR-106 cells.

The chemokine CXCL9 exacerbates chemotherapy-induced acute intestinal damage through inhibition of mucosal restitution

PURPOSE

Acute intestinal damage induced by chemotherapeutic agent is often a dose-limiting factor in clinical cancer therapy. The aim of this study was to investigate the effect of chemokine CXCL9 on the intestinal damage after chemotherapy and explore the therapeutic potential of anti-CXCL9 agents.

METHODS

In vitro cell proliferation assay was performed with a non-tumorigenic human epithelial cell line MCF10A. Multiple pathway analysis was carried out to explore the pathway that mediated the effect of CXCL9, and the corresponding downstream effector was identified with enzyme-linked immunosorbent assays. Chemotherapy-induced mouse model of intestinal mucositis was prepared by a single injection of the chemotherapeutic agent 5-fluorouracil (5-FU). In vivo expression of cxcl9 and its receptor cxcr3 in intestinal mucosa after chemotherapy was determined by quantitative real-time PCR. Therapeutic treatment with anti-CXCL9 antibodies was investigated to confirm the hypothesis that CXCL9 can contribute to the intestinal epithelium damage induced by chemotherapy.

RESULTS

CXCL9 inhibited the proliferation of MCF10A cells by activating phosphorylation of p70 ribosomal S6 kinase (p70S6K), which further promotes the secretion of transforming growth factor beta (TGF-β) as the downstream effector. A blockade of phospho-p70S6K with inhibitor abolished the effect of CXCL9 on MCF10A cells and reduced the secretion of TGF-β. The expression levels of cxcl9 and cxcr3 were significantly up-regulated in intestinal mucosa after 5-FU injection. Neutralizing elevated CXCL9 with anti-CXCR9 antibodies successfully enhanced reconstitution of intestinal mucosa and improved the survival rate of mice that received high-dose chemotherapy.

CONCLUSIONS

CXCL9 inhibits the proliferation of epithelial cells via phosphorylation of p70S6K, resulting in the excretion of TGF-β as downstream mediator. CXCL9/CXCR3 interaction can exacerbate chemotherapeutic agent-induced intestinal damage, and anti-CXCL9 agents are potential novel therapeutic candidates for promoting mucosal restitution.

Antifibrotic role of chemokine CXCL9 in experimental chronic pancreatitis induced by trinitrobenzene sulfonic acid in rats

Chemokines have been shown to play an important role in the pathogenesis of pancreatitis, but the role of chemokine CXCL9 in pancreatitis is poorly understood. The aim of this study was to investigate whether CXCL9 was a modulating factor in chronic pancreatitis. Chronic pancreatitis was induced in Sprague-Dawley rats by intraductal infusion of trinitrobenzene sulfonic acid (TNBS) and CXCL9 expression was assessed by immunohistochemistry, Western blot analysis and enzyme linked immunosorbent assay (ELISA). Recombinant human CXCL9 protein (rCXCL9), neutralizing antibody and normal saline (NS) were administered to rats with chronic pancreatitis by subcutaneous injection. The severity of fibrosis was determined by measuring hydroxyproline in pancreatic tissues and histological grading. The effect of rCXCL9 on activated pancreatic stellate cells (PSCs) in vitro was examined and collagen 1α1, TGF-β1 and CXCR3 expression was assessed by Western blot analysis in isolated rat PSCs. Chronic pancreatic injury in rats was induced after TNBS treatment and CXCL9 protein was markedly upregulated during TNBS-induced chronic pancreatitis. Although parenchymal injury in the pancreas was not obviously affected after rCXCL9 and neutralizing antibody administration, rCXCL9 could attenuate fibrogenesis in TNBS-induced chronic pancreatitis in vivo and exerted antifibrotic effects in vitro, suppressing collagen production in activated PSCs. In conclusion, CXCL9 is involved in the modulation of pancreatic fibrogenesis in TNBS-induced chronic pancreatitis in rats, and may be a therapeutic target in pancreatic fibrosis.