Reduced Colonic Mucosal Injury in 2,3,7,8-Tetrachlorodibenzo-p-Dioxin Poly ADP-Ribose Polymerase (TIPARP/PARP7)-Deficient Mice

Parps in immune response: Potential targets for cancer immunotherapy

Immunotherapy in clinical application faces numerous challenges pertaining to both effectiveness and safety. Poly(ADP-ribose) polymerases (PARPs) exhibit multifunctional characteristics by transferring ADP-ribose units to target proteins or nucleic acids. In recent years, more and more attention has been paid to the biological function of PARPs in immune response. This article reviews the relationship between PARP family members and immune response. PARP1 and PARP2 inhibit anti-tumor immune activity by regulating immune checkpoint expression and the cGAS/STING signaling pathway. PARP7 and PARP11 play an important role in promoting immunosuppressive tumor microenvironment. PARP9 promotes the production of Type I interferon and the infiltration of macrophages. PARP13 is a key tumor suppressor that promotes anti-tumor immune response. PARP14 plays a crucial role in promoting the differentiation of macrophages towards the M2 pro-tumor phenotype. Summarizing the molecular mechanisms of PARP7, PARP9, PARP11, PARP13 and PARP14 in regulating immune response is helpful to deepen our comprehension of the role of PARPs in immune function regulation. This provides a reference and basis for targeted PARP-based cancer treatment strategies and drug development. PARP1, PARP7 inhibitors or other PARP inhibitors in combination with immune checkpoint inhibitors or other immunotherapy strategies may be a more effective cancer therapy.

PARP7 as a new target for activating anti-tumor immunity in cancer

ADP-ribosyl transferases (ARTs) are a family of enzymes which catalyze the addition of a chain (PARylation) or a single moiety (MARylation) of ADP-ribose to their substrates. PARP7 is a mono-ADP-ribosyl transferase (mono-ART) which has recently gained attention due to its emerging role as a negative regulator of the type I interferon (IFN-I) and nuclear receptor signaling, and due to its aberrant expression in cancer, contributing to disease progression and immune evasion. PARP7-mediated ADP-ribosylation can differentially affect protein stability. On the one hand, PARP7-mediated ADP-ribosylation of the transcription factor FRA1 protects it from proteosomal degradation and thereby supports its function in negatively regulating IRF1 and the expression of apoptosis and immune signaling genes. On the other hand, PARP7-mediated ADP-ribosylation of aryl hydrocarbon receptor (AHR) and estrogen receptor (ER) marks them for proteosomal degradation. PARP7 also ADP-ribosylates the ligand-bound androgen receptor (AR), which is recognized by DTX3L-PARP9 that modulate the AR transcriptional activity. In this review, we discuss PARP7 enzymatic properties, biological functions and known substrates, its role in various cancers, and its targeting by specific inhibitors.

Polysaccharide from Atractylodes macrocephala Koidz Binding with Zinc Oxide Nanoparticles as a Novel Mucosal Immune Adjuvant for H9N2 Inactivated Vaccine

H9N2 avian influenza poses a significant public health risk, necessitating effective vaccines for mass immunization. Oral inactivated vaccines offer advantages like the ease of administration, but their efficacy often requires enhancement through mucosal adjuvants. In a previous study, we established a novel complex of polysaccharide from Atractylodes macrocephala Koidz binding with zinc oxide nanoparticles (AMP-ZnONPs) and preliminarily demonstrated its immune-enhancing function. This work aimed to evaluate the efficacy of AMP-ZnONPs as adjuvants in an oral H9N2-inactivated vaccine and the vaccine's impact on intestinal mucosal immunity. In this study, mice were orally vaccinated on days 0 and 14 after adapting to the environment. AMP-ZnONPs significantly improved HI titers, the levels of specific IgG, IgG1 and IgG2a in serum and sIgA in intestinal lavage fluid; increased the number of B-1 and B-2 cells and dendritic cell populations; and enhanced the mRNA expression of intestinal homing factors and immune-related cytokines. Interestingly, AMP-ZnONPs were more likely to affect B-1 cells than B-2 cells. AMP-ZnONPs showed mucosal immune enhancement that was comparable to positive control (cholera toxin, CT), but not to the side effect of weight loss caused by CT. Compared to the whole-inactivated H9N2 virus (WIV) group, the WIV + AMP-ZnONP and WIV + CT groups exhibited opposite shifts in gut microbial abundance. AMP-ZnONPs serve as an effective and safe mucosal adjuvant for oral WIV, improving cellular, humoral and mucosal immunity and microbiota in the gastrointestinal tract, avoiding the related undesired effects of CT.

TIPARP as a prognostic biomarker and potential immunotherapeutic target in male papillary thyroid carcinoma

BACKGROUND

Male patients with papillary thyroid carcinoma (PTC) tend to have poorer prognosis compared to females, partially attributable to a higher rate of lymph node metastasis (LNM). Developing a precise predictive model for LNM occurrence in male PTC patients is imperative. While preliminary predictive models exist, there is room to improve accuracy. Further research is needed to create optimized prognostic models specific to LNM prediction in male PTC cases.

METHODS

We conducted a comprehensive search of publicly available microarray datasets to identify candidate genes continuously upregulated or downregulated during PTC progression in male patients only. Univariate Cox analysis and lasso regression were utilized to construct an 11-gene signature predictive of LNM. TIPARP emerged as a key candidate gene, which we validated at the protein level using immunohistochemical staining. A prognostic nomogram incorporating the signature and clinical factors was developed based on the TCGA cohort.

RESULTS

The 11-gene signature demonstrated good discriminative performance for LNM prediction in training and validation datasets. High TIPARP expression associated with advanced stage, high T stage, and presence of LNM. A prognostic nomogram integrating the signature and clinical variables reliably stratified male PTC patients into high and low recurrence risk groups.

CONCLUSIONS

We identified a robust 11-gene signature and prognostic nomogram for predicting LNM occurrence in male PTC patients. We propose TIPARP as a potential contributor to inferior outcomes in males, warranting further exploration as a prognostic biomarker and immunotherapeutic target. Our study provides insights into the molecular basis for gender disparities in PTC.

Increased sensitivity to chemically induced colitis in mice harboring a DNA-binding deficient aryl hydrocarbon receptor

The aryl hydrocarbon receptor (AHR), a transcription factor best known for mediating toxic responses of environmental pollutants, also integrates metabolic signals to promote anti-inflammatory responses, intestinal homeostasis, and maintain barrier integrity. AHR regulates its target genes through direct DNA-binding to aryl hydrocarbon response elements (AHREs) but also through tethering to other transcription factors in a DNA-binding independent manner. However, it is not known if AHR's anti-inflammatory role in the gut requires its ability to bind to AHREs. To test this, we determined the sensitivity of Ahrdbd/dbd mice, a genetically modified mouse line that express an AHR protein incapable of binding to AHREs, to dextran sulfate sodium (DSS)-induced colitis. Ahrdbd/dbd mice exhibited more severe symptoms of intestinal inflammation than Ahr+/+ mice. None of the Ahrdbd/dbd mice survived after the 5-day DSS followed by 7-day washout period. By day 6, the Ahrdbd/dbd mice had severe body weight loss, shortening of the colon, higher disease index scores, enlarged spleens, and increased expression of several inflammation genes, including interleukin 1b (Il-1b), Il-6, Il-17, C-x-c motif chemokine ligand 1 (Cxcl1), Cxcl2, Prostaglandin-endoperoxide synthase (Ptgs2), and lipocalin-2. Our findings show that AHR's DNA-binding domain and ability to bind to AHREs are required to reduce inflammation, maintain a healthy intestinal environment, and protect against DSS-induced colitis.

Are PARPs promiscuous?

Post-translational modifications exist in different varieties to regulate diverse characteristics of their substrates, ultimately leading to maintenance of cell health. The enzymes of the intracellular poly(ADP-ribose) polymerase (PARP) family can transfer either a single ADP-ribose to targets, in a reaction called mono(ADP-ribosyl)ation or MARylation, or multiple to form chains of poly(ADP-ribose) or PAR. Traditionally thought to be attached to arginine or glutamate, recent data have added serine, tyrosine, histidine and others to the list of potential ADP-ribose acceptor amino acids. PARylation by PARP1 has been relatively well studied, whereas less is known about the other family members such as PARP7 and PARP10. ADP-ribosylation on arginine and serine is reversed by ARH1 and ARH3 respectively, whereas macrodomain-containing MACROD1, MACROD2 and TARG1 reverse modification of acidic residues. For the other amino acids, no hydrolases have been identified to date. For many PARPs, it is not clear yet what their endogenous targets are. Better understanding of their biochemical reactions is required to be able to determine their biological functions in future studies. In this review, we discuss the current knowledge of PARP specificity in vitro and in cells, as well as provide an outlook for future research.