Polysaccharides from Basella alba Protect Post-Mitotic Neurons against Cell Cycle Re-Entry and Apoptosis Induced by the Amyloid-Beta Peptide by Blocking Sonic Hedgehog Expression.

The amyloid-beta peptide (Aß) is the neurotoxic component in senile plaques of Alzheimer's disease (AD) brains. Previously we have reported that Aß toxicity is mediated by the induction of sonic hedgehog (SHH) to trigger cell cycle re-entry (CCR) and apoptosis in post-mitotic neurons. Basella alba is a vegetable whose polysaccharides carry immunomodulatory and anti-cancer actions, but their protective effects against neurodegeneration have never been reported. Herein, we tested whether polysaccharides derived from Basella alba (PPV-6) may inhibit Aß toxicity and explored its underlying mechanisms. In differentiated rat cortical neurons, Aß25-35 reduced cell viability, damaged neuronal structure, and compromised mitochondrial bioenergetic functions, all of which were recovered by PPV-6. Immunocytochemistry and western blotting revealed that Aß25-35-mediated induction of cell cycle markers including cyclin D1, proliferating cell nuclear antigen (PCNA), and histone H3 phosphorylated at Ser-10 (p-Histone H3) in differentiated neurons was all suppressed by PPV-6, along with mitigation of caspase-3 cleavage. Further studies revealed that PPV-6 inhibited Aß25-35 induction of SHH; indeed, PPV-6 was capable of suppressing neuronal CCR and apoptosis triggered by the exogenous N-terminal fragment of sonic hedgehog (SHH-N). Our findings demonstrated that, in the fully differentiated neurons, PPV-6 exerts protective actions against Aß neurotoxicity via the downregulation of SHH to suppress neuronal CCR and apoptosis.

Evaluation of Phototoxicity of Short-Wavelength Laser Light Utilizing PCNA Accumulation.

In recent years, diseases such as age-related macular degeneration and retinal pigment degeneration caused by excessive exposure to short-wavelength visible light have become significant concerns. With the aim of quantitatively evaluating the toxicity of short-wavelength light, proliferating cell nuclear antigen (PCNA) accumulation at the irradiation site was investigated using live cell imaging techniques to irradiate individual living cells with short-wavelength laser light. By examining the dependency of PCNA accumulation on the irradiation site within the cells and their cell cycle, it was observed that PCNA accumulation occurred only when the cell nucleus of cells in the S phase of the cell cycle was irradiated. We investigated the accumulation of PCNA at the laser irradiation site using laser light at wavelengths of 405 nm and 375 nm, with intensities ranging from 0.5 µW to 9.0 µW. The results confirmed an increase in PCNA accumulation with increasing intensity, and a higher accumulation was observed with laser light irradiation at a wavelength of 375 nm compared to 405 nm. By comparing the PCNA accumulation and 24 h cell viability, we demonstrated the feasibility of quantitatively assessing laser light toxicity through the measurement of PCNA accumulation.

Ehrlich ascites carcinoma provokes renal toxicity and DNA injury in mice: Therapeutic impact of chitosan and maitake nanoparticles.

In this study, the impact of chitosan (CS) and maitake (GF) nanoparticles towards the renal toxicity induced by Ehrlich ascites carcinoma (EAC) in vivo model was conducted. Besides benchmark negative control group, EAC model was constructed by intraperitoneal injection (i.p.) of 2.5 × 106 cells. Alongside positive control, two groups of EAC-bearing mice received 100 mg/kg of CS and GF nanoparticles/body weight daily for 14 days. The kidney function was conducted by measuring urea, creatinine, ions, (anti)/oxidative parameters and DNA damage. Also, measuring immunoreactivity of P53, proliferating cell nuclear antigen (PCNA), and B-cell lymphoma 2 (Bcl-2) and apoptosis protein. The outcomes illustrated notable kidney toxicity, which indicated by elevations in urea, creatinine, oxidative stress, DNA damage and induction of apoptosis. These events were supported by the drastic alteration in kidney structure through histological examination. Administration of CS and GF nanoparticles was able to enhance the antioxidant power, which further reduced oxidative damage, DNA injury, and apoptosis. These results indicated the protective and therapeutic role of biogenic chitosan and maitake nanoparticles against nephrotoxicity.

Evaluation of mutations on O6-methylguanine methyl transferase structure and its interactions: molecular dynamics simulation study.

O6-methylguanine DNA methyl transferase (MGMT) is a significant vehicle for the cellular clearance of alkyl lesions, particularly the methyl group of the O-6 and O-4 positions of guanine and thymine, respectively. Many publications have studied the correlation between polymorphisms in MGMT and susceptibility to various cancers. In the present study, we investigated the consequence of L84F, common single-nucleotide polymorphism, K125E, site-specific mutagenesis, and L84F/K125E on conformation, stability, and behavior of MGMT in the free form and interaction with proliferating cell nuclear antigen (PCNA) and DNA as partners in the biochemical network by using molecular dynamics simulation method. Our results showed that all free variants of MGMT differed from the native form. However, among all free variants of MGMT, the L84F/K125E variant exhibited similar properties compared with the wild-type. In contrast, in complex modes, only amino acid residues of the L84F variant are involved in the interactions with PCNA and DNA somewhat differently relative to the wild-type. Furthermore, L84F SNP showed the highest binding free energy compared to other variants and native forms. These alterations in the amino acids and binding free energy of L84F relative to the native are the reasons for changing its region connection compared to the native form. Therefore, we propose conducting further investigations into the impact of inhibitors or chemotherapeutic agents to assess their effectiveness on MGMT variants compared to the wild-type, aiming to reduce the cost of cancer treatment that will depend on inhibiting native MGMT protein.Communicated by Ramaswamy H. Sarma.

Squalene monooxygenase facilitates bladder cancer development in part by regulating PCNA.

Bladder cancer (BC) is one of the most common cancers worldwide. Although the treatment and survival rate of BC are being improved, the risk factors and the underlying mechanisms causing BC are incompletely understood. Squalene monooxygenase (SQLE) has been associated with the occurrence and development of multiple cancers but whether it contributes to BC development is unclear. In this study, we performed bioinformatics analysis on paired BC and adjacent non-cancerous tissues and found that SQLE expression is significantly upregulated in BC samples. Knockdown of SQLE impairs viability, induces apoptosis, and inhibits the migration and invasion of BC cells. RNA-seq data reveals that SQLE deficiency leads to dysregulated expression of genes regulating proliferation, migration, and apoptosis. Mass spectrometry-directed interactome screening identifies proliferating cell nuclear antigen (PCNA) as an SQLE-interacting protein and overexpression of PCNA partially rescues the impaired viability, migration, and invasion of BC cells caused by SQLE knockdown. In addition, we performed xenograft assays and confirmed that SQLE deficiency inhibits BC growth in vivo. In conclusion, these data suggest that SQLE promotes BC development and SQLE inhibition may be therapeutically useful in BC treatment.

mAb14, a Monoclonal Antibody against Cell Surface PCNA: A Potential Tool for Sezary Syndrome Diagnosis and Targeted Immunotherapy.

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common types of primary cutaneous T-cell lymphoma (CTCL). Proliferating cell nuclear antigen (PCNA) is expressed on the cell surface of cancer cells (csPCNA), but not on normal cells. It functions as an immune checkpoint ligand by interacting with natural killer (NK) cells through the NK inhibitory receptor NKp44, leading to the inhibition of NK cytotoxicity. A monoclonal antibody (mAb14) was established to detect csPCNA on cancer cells and block their interaction with NKp44. In this study, three CTCL cell lines and peripheral blood mononuclear cells (PBMCs) from patients with SS and healthy donors were analyzed for csPCNA using mAb14, compared to monoclonal antibody PC10, against nuclear PCNA (nPCNA). The following assays were used: immunostaining, imaging flow cytometry, flow cytometry, cell sorting, cell cycle analysis, ELISA, and the NK-cell cytotoxic assay. mAb14 successfully detected PCNA on the membrane and in the cytoplasm of viable CTCL cell lines associated with the G2/M phase. In the Sézary PBMCs, csPCNA was expressed on lymphoma cells that had an atypical morphology and not on normal cells. Furthermore, it was not expressed on PBMCs from healthy donors. In the co-culture of peripheral blood NK (pNK) cells with CTCL lines, mAb14 increased the secretion of IFN-γ, indicating the reactivation of pNK activity. However, mAb14 did not enhance the cytotoxic activity of pNK cells against CTCL cell lines. The unique expression of csPCNA detected by mAb14 suggests that csPCNA and mAb14 may serve as a potential biomarker and tool, respectively, for detecting malignant cells in SS and possibly other CTCL variants.

Garcinol-Attenuated Gastric Ulcer (GU) Experimentally Induced in Rats Via Affecting Inflammation, Cell Proliferation, and DNA Polymerization.

BACKGROUND:  Gastric ulcer (GU) is one of the most critical gastrointestinal tract disorders. Garcinol is a polyisoprenylated benzophenone in Garcinia fruit with antioxidant and anti-inflammatory priorities. OBJECTIVES:  We aimed to assess the protective effects of garcinol against GU induced in rats. We investigated garcinol's effects on DNA polymerization via mammalian targets of rapamycin (mTOR) and cyclin D1, cell proliferation via proliferating cell nuclear antigen (PCNA), inflammatory pathway via cyclooxygenase-2 (COX2), TNF-α, and IL-1ß, and anti-inflammatory pathway via IL-4 and IL10. METHODS:  In our study, we administered a single oral dose of 80 mg/kg of indomethacin to rats to induce GU. Some of the rats were given a treatment of 50 mg/kg of garcinol. We examined the expressions of mTOR, cyclin D1, PCNA, COX2, TNF-α, and IL-1ß/4/10 in the gastric tissues. Furthermore, we stained sections of the gastric tissues with Masson trichrome. RESULTS:  The areas of gastric tissues in the GU group showed severe hemorrhage and extensive fibrosis. Treating GU rats with garcinol prevented bleeding and ameliorated the fibrosis caused in gastric cells by GU. Moreover, treatment with garcinol significantly decreased the expression of mTOR, cyclin D1, PCNA, COX2, TNF-α, and IL-1ß associated with elevation of IL-4 and IL-10. CONCLUSION:  Garcinol has been found to provide therapeutic benefits in rats with induced GU. These benefits may be due to its ability to decrease the expression of DNA polymerization markers, cell proliferation markers, and inflammatory markers at the gene and protein levels.

Micro Ribonucleic Acid-29a (miR-29a) Antagonist Normalizes Bone Metabolism in Osteogenesis Imperfecta (OI) Mice Model.

Osteogenesis imperfecta (OI) is not curative nowadays. This study tried to unriddle the therapeutic potential of micro ribonucleic acid-29a (miR-29a) antagonist in treating OI in a mouse animal model (B6C3Fe a/a-Col1a2oim/J). We showed that the expression levels of miR-29a were higher in bone tissues obtained from the OI mice than from wild-type mice demonstrated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and in situ hybridization assay. We established lentivirus-shuttled vector expressing miR-29a antisense oligonucleotide (miR-29a-AS) and miR-29a precursors (pre-miR-29a), showing that the inferior bony architecture in micro-computed tomography and pertinent morphometric parameters could be rescued by miR-29a-AS and deteriorated by pre-miR-29a. The decreased proliferating cell nuclear antigen (PCNA), increased Dickkopf-1 (DKK1), and decreased ß-catenin expression in OI mice could be accentuated by pre-miR-29a and normalized by miR-29a-AS. The decreased osteogenesis and increased osteoclastogenesis in OI mice could also be accentuated by pre-miR-29a and normalized by miR-29a-AS. miR-29a-AS did not seem to possess severe hepatic or renal toxicities.

ROS and DNA repair in spontaneous versus agonist-induced NETosis: Context matters.

Reactive oxygen species (ROS) is essential for neutrophil extracellular trap formation (NETosis). Nevertheless, how ROS induces NETosis at baseline and during neutrophil activation is unknown. Although neutrophils carry DNA transcription, replication and repair machineries, their relevance in the short-lived mature neutrophils that carry pre-synthesized proteins has remained a mystery for decades. Our recent studies show that (i) NETosis-inducing agonists promote NETosis-specific kinase activation, genome-wide transcription that helps to decondense chromatin, and (ii) excess ROS produced by NADPH oxidase activating agonists generate genome-wide 8-oxy-guanine (8-OG), and the initial steps of DNA repair are needed to decondense chromatin in these cells. These steps require DNA repair proteins necessary for the assembly and nicking at the damaged DNA sites (poly ADP ribose polymerase PARP, apurinic endonuclease APE1 and DNA ligase), but not the enzymes that mediate the repair DNA synthesis (Proliferating cell nuclear antigen (PCNA) and DNA Polymerases). In this study, we show that (i) similar to agonist-induced NETosis, inhibition of early steps of oxidative DNA damage repair proteins suppresses spontaneous NETosis, but (ii) the inhibition of late stage repair proteins DNA polymerases and PCNA drastically promotes baseline NETosis. Hence, in the absence of excessive ROS generation and neutrophil activation, DNA repair mediated by PCNA and DNA polymerases is essential to prevent chromatin decondensation and spontaneous NETosis. These findings indicate that ROS, oxidative DNA damage, transcription and DNA repair differentially regulate spontaneous and agonist-induced NETosis. Therefore, context matters.

Therapeutic effects of sulforaphane in ulcerative colitis: effect on antioxidant activity, mitochondrial biogenesis and DNA polymerization.

OBJECTIVES: Ulcerative colitis (UC), an inflammatory bowel disease, affects mucosal lining of colon leading to inflammation and ulcers. Sulforaphane is a natural compound obtained from cruciferous vegetables. We aimed to investigate potential therapeutic effects of sulforaphane in experimentally induced UC in rats through affection antioxidant activity, mitochondrial biogenesis and DNA polymerization. METHODS: UC was induced in rats via an intracolonic single administration of 2 ml of 4% acetic acid. UC rats were treated with 15 mg/kg sulforaphane. Samples of colon were used to investigate gene expression and protein levels of peroxisome proliferator-activated receptor-gamma coactivator (PGC-1), mitochondrial transcription factor A (TFAM), mammalian target of rapamycin (mTOR), cyclin D1, nuclear factor erythroid 2-related factor-2 (Nrf2), heme Oxygenase-1 (HO-1) and proliferating cell nuclear antigen (PCNA). RESULTS: UC showed dark distorted Goblet cell nucleus with disarranged mucus granules and no distinct brush border with atypical microvilli. All morphological changes were improved by treating with sulforaphane. Finally, treatment with sulforaphane significantly increased expression of PGC-1, TFAM, Nrf2 and HO-1 associated with reduction in expression of mTOR, cyclin D1 and PCNA. CONCLUSION: Sulforaphane could cure UC in rats. The protective activity can be explained by enhancing antioxidant activity, elevating mitochondrial biogenesis and inhibiting DNA polymerization.

MMP2/9 downregulation is responsible for hepatic function recovery in cirrhotic rats following associating liver partition and portal vein ligation for staged hepatectomy.

Background: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was introduced in 2007. The current study explored the mechanisms of rapid liver hypertrophy after ALPPS in cirrhotic rats. Methods: A cirrhotic rat model was constructed and portal vein ligation (PVL) or ALPPS treatments were administered. The liver hyperplasia rate of the rats was calculated, and hepatic function was evaluated using biochemical factors and the indocyanine green excretion test. Subsequently, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and hematoxylin and eosin (HE) staining were performed to determine the degree of liver regeneration. Differentially expressed genes during the rapid liver hypertrophy were detected by bioinformatics analysis, followed verification using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Results: The body weight of rats that underwent PVL and ALPPS changed during the first 1-4 days postoperatively, and the alterations were more pronounced in rats receiving ALPPS. The recovery of body weight in cirrhotic rats was slower than that in normal rats. The levels of biochemical factors and the indocyanine green retention rate increased 1 day after PVL and ALPPS, and then decreased gradually. PVL and ALPPS elevated the levels of cytokines, inflammatory factors, and proliferating cell nuclear antigen (PCNA) in rats at 1 day postoperatively. HE observation of rat liver condition showed that rats recovered faster within the first 4 days postoperatively. ALPPS surgery resulted in a significant downregulation of matrix metalloproteinase (MMP)2/9 expression in cirrhotic rats at postoperative day 4. Conclusions: Liver function was partially recovered in cirrhotic rats after ALPPS, and the underlying mechanisms may involve PCNA and MMP2/9.

Replication and transcription machinery for ranaviruses: components, correlation, and functional architecture.

BACKGROUND: Ranaviruses (family Iridoviridae) are promiscuous pathogens that can infect across species barriers in poikilotherms and can replicate in amphibian and fish cells and even in cultured mammalian cells. However, as nucleocytoplasmic large DNA viruses (NCLDVs), their replication and transcription mechanisms remain largely unknown. Here, we screened and uncovered the replication and transcription machinery of two ranaviruses, Andrias davidianus ranavirus (ADRV) and Rana grylio virus (RGV), by a combination of methods, including the isolation of proteins on nascent DNA, recombinant virus-based affinity, and NanoLuc complementation assay. RESULTS: The ranavirus replication and transcription machinery was deeply dissected and identified as a complicated apparatus containing at least 30 viral and 6 host proteins. The viral proteins ADRV-47L/RGV-63R (DNA polymerase, vDPOL), ADRV-23L/RGV-91R (proliferating cell nuclear antigen, vPCNA), ADRV-85L/RGV-27R (single-stranded DNA binding protein, vSSB), ADRV-88L/RGV-24R (vhelicase/primase), etc., constitute the core replisome. Specifically, the core of the transcription complex, the viral RNA polymerase, contain the host RNAPII subunits Rpb3, Rpb6, and Rpb11, which was a first report in NCLDVs. Furthermore, correlations and interactions among these factors in the machinery were described. Significantly, the replisome core protein vDPOL (ADRV-47L) can interact with numerous viral and host proteins and could act as a linker and regulation center in viral DNA replication and transcription. Thus, these results depicted an architecture for ranavirus replication and transcription. CONCLUSIONS: Up to 36 components from ranavirus and their host were found to form viral replisomes and transcription complexes using a series of precise methods, which further constructed an architecture for ranavirus replication and transcription in which vDPOL was a key central factor and various components correlated and cooperated. Therefore, it provides a cornerstone for further understanding the mechanisms of the replication and transcription of ranaviruses which can ensure the efficient production of progeny virus and adaptation to cross-species infection.

Bioinformatics analysis of the prognostic biomarkers and predictive accuracy of differentially expressed genes in high-risk multiple myeloma based on Gene Expression Omnibus database mining.

Background: Multiple myeloma (MM) is still an intractable disease for modern clinical system, and more researches are necessary for development of more effective therapeutic strategies. This study attempted to screen and validates the biomarkers in the progression of MM via excavating Gene Expression Omnibus (GEO) database. Identification of a biomarker may help not only facilitate early diagnosis and management but also identify individuals at risk for poor prognosis and development of MM. Methods: The mRNA expression profile of the GSE87900 dataset was analyzed by GEO2R. Using the SangerBox online program, differentially expressed genes (DEGs) in high-risk MM samples were screened with the filter criteria of P<0.05 and |logFC| >1. The SangerBox online analysis tool was used to analyze the volcano plot. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed for DEGs. Twenty patients with high-risk MM and 20 patients with standard-risk MM from Taian City Central Hospital were included. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to verify the selected key genes in MM tissues. Results: A total of 611 DEGs were obtained. GO functional enrichment analysis showed that the DEGs were mainly enriched in the DNA replication process at the biological level, and the top DEGs were CACYBP, PCNA, MCM6, SMC1A, DTL, GINS4, MCM2, CDT1, RRM2, BRCA1, RFC5, MCM4, GINS3, GINS1, MCM10, CDC7, CDAN1, BRIP1, GINS2, CDK1, NFIB, and BARD1. The expression of CDC7 and PCNA was significantly different in high-risk MM and standard-risk MM as determined by RT-qPCR. Receiver operating characteristic (ROC) analysis showed that the areas under the curve predicted by CDC7 and PCNA were 0.900 and 0.8863, respectively, which allowed the identification of CDC7 and PCNA could be a potential biomarker of MM. Kaplan-Meier survival analysis showed that MM patients with high CDC7 and PCNA expression had shorter 2-year overall survival (OS) (P<0.05). Conclusions: CDC7 and PCNA can be used as biomarkers for the prognosis of high-risk MM and evaluate the prognosis of MM patients, which is helpful for guiding the clinical treatment of MM patients.

Unlocking the PIP-box: A peptide library reveals interactions that drive high-affinity binding to human PCNA.

The human sliding clamp, Proliferating Cell Nuclear Antigen (hPCNA), interacts with over 200 proteins through a conserved binding motif, the PIP-box, to orchestrate DNA replication and repair. It is not clear how changes to the features of a PIP-box modulate protein binding and thus how they fine-tune downstream processes. Here, we present a systematic study of each position within the PIP-box to reveal how hPCNA-interacting peptides bind with drastically varied affinities. We synthesized a series of 27 peptides derived from the native protein p21 with small PIP-box modifications and another series of 19 peptides containing PIP-box binding motifs from other proteins. The hPCNA-binding affinity of all peptides, characterized as KD values determined by surface plasmon resonance, spanned a 4000-fold range, from 1.83 nM to 7.59 µM. The hPCNA-bound peptide structures determined by X-ray crystallography and modeled computationally revealed intermolecular and intramolecular interaction networks that correlate with high hPCNA affinity. These data informed rational design of three new PIP-box sequences, testing of which revealed the highest affinity hPCNA-binding partner to date, with a KD value of 1.12 nM, from a peptide with PIP-box QTRITEYF. This work showcases the sequence-specific nuances within the PIP-box that are responsible for high-affinity hPCNA binding, which underpins our understanding of how nature tunes hPCNA affinity to regulate DNA replication and repair processes. In addition, these insights will be useful to future design of hPCNA inhibitors.

A turn-on fluorescent PCNA sensor.

The solvatochromic amino-acids 4-DMNA or 4-DAPA, were separately introduced at position 147, 150 or 151 of a short p21 peptide (141-155) known to bind sliding clamp protein PCNA. The ability of these peptides, 1a-3a and 1b-3b, to act as a turn-on fluorescent sensor for PCNA was then investigated. The 4-DMNA-containing peptides (1a-3a) displayed up to a 40-fold difference in fluorescence between a polar (Tris buffer) and a hydrophobic solvent (dioxane with 5 mM 18-crown-6), while the 4-DAPA-containing peptides (1b-3b) displayed a significantly enhanced (300-fold) increase in fluorescence from Tris buffer to dioxane with 18-crown-6. SPR analysis of the peptides against PCNA revealed that the 151-substituted peptides 3a and 3b interacted specifically with PCNA, with KD values of 921 nM and 1.28 µM, respectively. Analysis of the fluorescence of these peptides in the presence of increasing concentrations of PCNA revealed a 10-fold change in fluorescence for 3a at 2.5 equivalents of PCNA, compared to only a 3.5-fold change in fluorescence for 3b. Peptide 3a is an important lead for development of a PCNA-selective turn-on fluorescent sensor for application as a cell proliferation sensor to investigate diseases such as cancer.

Age and insulin-like growth factor-1 impact PCNA monoubiquitination in UVB-irradiated human skin.

Nonmelanoma skin cancers occur primarily in individuals over the age of 60 and are characterized by an abundance of ultraviolet (UV) signature mutations in keratinocyte DNA. Though geriatric skin removes UV photoproducts from DNA less efficiently than young adult skin, it is not known whether the utilization of other prosurvival but potentially mutagenic DNA damage tolerance systems such as translesion synthesis (TLS) is altered in older individuals. Using monoubiquitination of the replicative DNA polymerase clamp protein PCNA (proliferating cell nuclear antigen) as a biochemical marker of TLS pathway activation, we find that UVB exposure of the skin of individuals over the age of 65 results in a higher level of PCNA monoubiquitination than in the skin of young adults. Furthermore, based on previous reports showing a role for deficient insulin-like growth factor-1 (IGF-1) signaling in altered UVB DNA damage responses in geriatric human skin, we find that both pharmacological inhibition of the IGF-1 receptor (IGF-1R) and deprivation of IGF-1 potentiate UVB-induced PCNA monoubiquitination in both human skin ex vivo and keratinocytes in vitro. Interestingly, though the TLS DNA polymerase Pol eta can accurately replicate the major photoproducts induced in DNA by UV radiation, we find that it fails to accumulate on chromatin in the absence of IGF-1R signaling and that this phenotype is correlated with increased mutagenesis in keratinocytes in vitro. Thus, altered IGF-1/IGF-1R signaling in geriatric skin may predispose epidermal keratinocytes to carry out a more mutagenic form of DNA synthesis following UVB exposure.

The effects of proliferating cell nuclear antigen and p53 in patients with oral squamous cell carcinoma: a systematic review and meta-analysis.

BACKGROUND: To evaluate the effect of proliferating cell nuclear antigen (PCNA) and p53 in patients with oral squamous cell carcinoma (OSCC). METHODS: Multiple databases, including PubMed, Embase, Cochrane library, and China National Knowledge Database, were searched for relevant studies and full-text articles that evaluated the effect of PCNA and p53 in patients with OSCC. Review Manager 5.2 was adopted to estimate the impact of the results among the selected articles. Forest plots, NOS table, sensitivity analysis, and bias analysis were also conducted. RESULTS: In total, nine eligible studies satisfied the included criteria. High PCNA expression (>50%) was significantly more prevalent in OSCC than low PCNA expression (<50%) (OR =3.88; 95% CI: 2.04-7.37; P<0.0001; I2=0%). However, there was no significant difference between p53 and OSCC (OR =1.60; 95% CI: 0.18-14.63; P=0.68; I2=86%). Low PCNA expression had a higher 5-year overall survival in OSCC patients than high PCNA expression (OR =0.47; 95% CI: 0.27-0.80; P=0.005; I2=41%). Meanwhile, p53 negative had a higher 5-year overall survival than p53 positive (OR =0.20; 95% CI: 0.10-0.42; P<0.0001; I2=0%). There was no difference between high and low PCNA in terms of metastasis (OR =0.80 with 95% CI: 0.18-3.45, I2=63%, P of over effect =0.76). The overall results showed no difference between p53 and metastasis (OR =0.38 with 95% CI: 0.13-1.10, I2=0%, P of over effect =0.07). DISCUSSION: PCNA and p53 might be suitable for prognostic and survival evaluation in OSCC patients.

The ameliorative effect of curcumin on cryptorchid and non-cryptorchid testes in induced unilateral cryptorchidism in albino rat: histological evaluation.

BACKGROUND: Cryptorchidism, one or both hidden testes, is the most common abnormality of male sexual development. Subfertility or infertility is associated with both unilateral and bilateral cryptorchidism. In this study, we investigate the possible ameliorative effect of curcumin (Cur) on the induced-unilateral cryptorchidism testicular injury in both cryptorchid (Cryp) and non-cryptorchid (non-Cryp) scrotal testes through histological, immunohistochemical and morphometrics. MATERIALS AND METHODS: Forty adult male albino rats were divided into: control group, Cur control group, Cryp group, and Cryp+Cur group. The rat model was surgically established by fixing the left testis in the abdomen. The treated groups were subjected to surgically induced-unilateral cryptorchidism on the left side then were given Cur (80 mg/kg) orally, for 20 days. Histological analysis using haematoxylin and eosin and periodic acid Schiff's reaction was done. Immunohistochemistry was performed for proliferating cell nuclear antigen (PCNA); to estimate the proliferation in the germinal epithelium, and vimentin; to evaluate Sertoli cells. The results were confirmed by statistical evaluation of the spermatogenic epithelium height, the seminiferous tubules diameter, the basement membrane thickness, the number of PCNA immunostained cells and the area per cent of vimentin immunostaining. RESULTS: Distorted seminiferous tubules, substantial degeneration of the germinal epithelium, thickening of the basement membrane with a significant decrease in PCNA and vimentin immunostaining were observed in Cryp group; mainly in the cryptorchid testis. These structural changes were significantly reversed in Crypt+Cur group. CONCLUSIONS: Curcumin proved to be an important and effective medical line for protecting against the unfavourable sequels of cryptorchidism in a rat model.

Multi-Omics Integration Highlights the Role of Ubiquitination in CCl4-Induced Liver Fibrosis.

Liver fibrosis is the excessive accumulation of extracellular matrix proteins that occurs in chronic liver disease. Ubiquitination is a post-translational modification that is crucial for a plethora of physiological processes. Even though the ubiquitin system has been implicated in several human diseases, the role of ubiquitination in liver fibrosis remains poorly understood. Here, multi-omics approaches were used to address this. Untargeted metabolomics showed that carbon tetrachloride (CCl4)-induced liver fibrosis promotes changes in the hepatic metabolome, specifically in glycerophospholipids and sphingolipids. Gene ontology analysis of public deposited gene array-based data and validation in our mouse model showed that the biological process "protein polyubiquitination" is enriched after CCl4-induced liver fibrosis. Finally, by using transgenic mice expressing biotinylated ubiquitin (bioUb mice), the ubiquitinated proteome was isolated and characterized by mass spectrometry in order to unravel the hepatic ubiquitinated proteome fingerprint in CCl4-induced liver fibrosis. Under these conditions, ubiquitination appears to be involved in the regulation of cell death and survival, cell function, lipid metabolism, and DNA repair. Finally, ubiquitination of proliferating cell nuclear antigen (PCNA) is induced during CCl4-induced liver fibrosis and associated with the DNA damage response (DDR). Overall, hepatic ubiquitome profiling can highlight new therapeutic targets for the clinical management of liver fibrosis.

Multisite SUMOylation restrains DNA polymerase η interactions with DNA damage sites.

Translesion DNA synthesis (TLS) mediated by low-fidelity DNA polymerases is an essential cellular mechanism for bypassing DNA lesions that obstruct DNA replication progression. However, the access of TLS polymerases to the replication machinery must be kept tightly in check to avoid excessive mutagenesis. Recruitment of DNA polymerase η (Pol η) and other Y-family TLS polymerases to damaged DNA relies on proliferating cell nuclear antigen (PCNA) monoubiquitylation and is regulated at several levels. Using a microscopy-based RNAi screen, here we identified an important role of the SUMO modification pathway in limiting Pol η interactions with DNA damage sites in human cells. We found that Pol η undergoes DNA damage- and protein inhibitor of activated STAT 1 (PIAS1)-dependent polySUMOylation upon its association with monoubiquitylated PCNA, rendering it susceptible to extraction from DNA damage sites by SUMO-targeted ubiquitin ligase (STUbL) activity. Using proteomic profiling, we demonstrate that Pol η is targeted for multisite SUMOylation, and that collectively these SUMO modifications are essential for PIAS1- and STUbL-mediated displacement of Pol η from DNA damage sites. These findings suggest that a SUMO-driven feedback inhibition mechanism is an intrinsic feature of TLS-mediated lesion bypass functioning to curtail the interaction of Pol η with PCNA at damaged DNA to prevent harmful mutagenesis.