Biomolecules

The intracellular transport system is pivotal for cellular function and integrity, facilitated by cytoskeletal motor proteins such as dynein, which traverse along microtubules (MTs). The heterogeneity of the tubulin isotypes composing MTs introduces functional diversity, potentially affecting cytoskeletal motor proteins interactions with the MT. This in silico study investigated the influence of amino acid sequence variations in the C-terminal tails (CTTs) of six different Homo sapiens tubulin isotypes, TUBB2A, TUBB2B, TUBB2C, TUBB3, TUBB4A, and TUBB5, highly expressed in human brain tumors, and assessed the isotypes effect on the binding of motor protein dynein to MT. Among these isotypes, TUBB2A, TUBB2B, and TUBB2C were found to affect conformational motions of the dyneins microtubule-binding domain (MTBD) and stalk domain. The investigation highlighted the novel role of isotype-specific variations in lateral interactions between tubulin protofilaments (PFs) in determining the proximity of the {beta}-CTT of the adjacent PF to the MTBD, potentially affecting dyneins motility and suggesting how changes in isotype expression directly influence dyneins velocity and processivity and contribute to transport defects associated with neurological disorders and cancers. Isolating specific tubulin isotypes experimentally is challenging due to their high sequence similarity and complex interactions with other microtubule-associated proteins. This makes it challenging to distinguish between different tubulin isotypes and their effects, particularly in tissues where multiple isotypes are co-expressed. Additionally, these isotypes are heavily modified in vivo by post-translational modifications, which further complicate the isolation of a single, unmodified tubulin isotype. As a result, computational approaches have been necessary in this study for exploring these effects in a controlled, isotype-specific manner.

Intrinsically disordered proteins (IDP) or proteins with intrinsically disordered regions (IDR) perform a plethora of functions mostly in a cellular environment. As unfolded proteins, IDPs can adopt molten globule or coil ensembles of conformations. Regarding the latter the question arises whether they are describable as a self-avoiding random coil. Locally, this requires that amino acid residues sample the entire sterically allowed region of the Ramachandran plot with very similar probabilities and independent on the conformational dynamics of their neighbours. However, various lines of experimental and bioinformatic evidence suggest a more restricted, side chain and nearest neighbor dependent conformational space for individual residues. Over the last 25 years short peptides and coil libraries were employed to determine conformational propensities of amino acid residues in unfolded states. The question arises whether conformational ensembles obtained from these two sources are comparable. In this paper, a variety of metrics were used to compare Ramachandran plots of a limited number of GXYG peptides (X,Y: guest residues) with XY dimers in the coil library of Ting et al.(PLOS 6, e1000763, 2010). The results reveal major differences between corresponding plots, which might in part due to the fact that solely the influence of one of the two neighbours of a given residue is probed by the above coil library while averages were taken over the respective opposite neighbours. The presented results suggest that coil libraries alone might not be a sufficient tool for determining the characteristics of statistical coils of IDPS and IDRs alike.

The MYC associated factor X (MAX) is the heterodimeric partner of the MYC paralogs (MYC, MYCN and MYCL). When deregulated, high level of the MYC paralogs contribute to all aspects of tumorigenesis and tumor growth. MAX can also heterodimerize with the MXD proteins, MNT and MGA. Heterodimerization and sequence specific DNA binding to the E-Box sequences at gene promoters is controlled by their heterodimerization with the MAX b-HLH-LZ. As a heterodimer with MAX, MYC proteins activate genes involved in cell metabolism, growth and proliferation whereas MXD proteins, MNT and MGA repress them. MAX can also bind to the E-Bos sequence as a homodimer. Being devoid of a transactivation domain it can act as an antagonist of the MYC/MAX heterodimers. Variants of MAX have been reported to be linked to cancer. These variants are either not expressed, inactivated or lead to missense mutations. This has led to the notion that MAX may have a tumor suppressor role. Here, we characterize three of those variants with missense mutations in the basic region, i.e. E32K, R35P and R35C. We analyzed their heterodimerization with the b-HLH-LZ of MYC and their DNA binding properties as homo-and heterodimers. The R35C variant b-HLH-LZ was found to have a markedly increased affinity for the b-HLH-LZ of MYC. We also observed that all three b-HLH-LZ variants have a lower affinity as homodimers for the E-Box than the WT. This was shown to lead to a preferential binding of all the heterodimeric b-LHLH-LZ to the E-Box. This effect is exacerbated in the case of the R35C variant. We argue that this preferential binding of MYC as heterodimers with these variants to E-Box sequences could contribute to tumorigenesis. Hence, our results suggest that, mechanistically, the MAX homodimer bound to the E-Box could act as a tumor suppressor. MATERIALS AND METHODSO_ST_ABSMolecular modelingC_ST_ABSThe open source version 1.7.6.0 of Pymol was used for modeling and molecular rendering [1]. The crystal structure of the MAX homodimer bound to the E-Box (1HLO [2]) was used as a template for the generation of the models. The variants were generated using the mutagenesis function in the wizard. The conformation of the K32 side chain was manually set in order to avoid introducing steric clashes with DNA. Protein expression and purificationThe cDNA, coding for the MAX b-HLH-LZ (Max* hereafter, residues 22-103, UniProt entry P61244-1) to which are added the GSGC residues in c-terminal, inserted in the pET3a vector was already available in the laboratory [3] and was used as a template to generate the plasmids with inserts coding for each of the mutants (E32K, R35C and R35P) through quick-change PCR with Q5 DNA polymerase and DpnI from New England Biolabs. The primers used were purchased from IDT DNA, their sequences are listed in Table S1. Sequence for each construct was confirmed by Sanger sequencing at the Plateforme de sequencage SANGER - Centre de recherche du CHU de Quebec - Universite Laval. The primary structure for the basic region of each construct is given in Fig. 2A. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=137 SRC="FIGDIR/small/715400v1_fig2.gif" ALT="Figure 2"> View larger version (41K): org.highwire.dtl.DTLVardef@1b05d5eorg.highwire.dtl.DTLVardef@1c1d692org.highwire.dtl.DTLVardef@ee469dorg.highwire.dtl.DTLVardef@15e0ba4_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 2.C_FLOATNO Structure schematics, specific and non-specific interactions dictating specificity and stability of binding of the basic region of MAX to the canonical (CACGTG) E-Box. A. Primary structure for the basic region of MAX and each of the variants. Positions making the most important contacts with the E-box are indicated by black arrows. Positions for the variants studied here are colored according to the Zappo colour scheme, following their physico-chemical properties: red for negative, blue for positive, magenta for proline and yellow for cysteine. B. The side chain (carboxylate) of E32 receives H-Bonds from the CA nucleobases in the leading strand (white carbon atoms). R35 and R36 make a salt bridges with phosphate groups while and the guanidino moiety of R36 makes a specific H-Bond with the nucleobase of the G in the strand of the reverse complement (cyan carbon atoms). C. The R35C mutation removes one non-specific salt-bridge at the interface of the complex. D. The aliphatic portion of the K side chain in the E32K variant is unable to accept the H-Bonds from the CA nucleobases and leads to the stabilisation of the complex and the helical structure of the basic region. E. In addition to removing a salt-bride, the Pro residue in the R35P kinks the path of the basic region, prevents the establishment of the specific H-Bonds mandatory for recognition of the E-Box and leads to unfolding of the helical state. C_FIG The MYC b-HLH-LZ (Myc*), the Max*WT b-HLH-LZ and its variants were expressed and purified as previously described [3,4] After lyophilisation, the b-HLH-LZs were kept at -20{degrees}C and solubilised in Myc buffer (50 mM NaCl, 50 mM NaH2PO4 pH 5.5) for Myc* or PBS for Max* at a final concentration of 1 mM before use. Circular dichroismAll circular dichroism (CD) measurements were performed on a Jasco J-810 spectropolarimeter equipped with a Peltier-type thermostat. The instrument was routinely calibrated using an aqueous solution of d-10-(+)-camphorsulfonic acid at 290.5 nm. Samples were prepared as follows: Max* (either WT or a variant) was diluted in 100 {micro}l 2X CD buffer (40 mM KCl, 11.4 mM K2HPO4, 28.6 mM KH2PO4, pH 6.8) and the volume adjusted to 106 {micro}l with PBS. 10 {micro}l TCEP 16 mM were added, and the volume further adjusted to 192 {micro}l with ddH2O before samples were incubated overnight at room temperature. After reduction, Myc* was added and the volume adjusted to 198 {micro}l with Myc buffer (Na2HPO4 0.95 mM, NaH2PO4 49.05 mM, 50 mM NaCl, pH 5.5). The DNA complexes were prepared as follows. After a 10 minutes incubation of the protein samples at room temperature, 0, 1 or 2 {micro}l of 2 mM of specific or non-specific DNA duplexes in 10 mM Tris pH 8.0 were added and the volume adjusted to 200 {micro}l with 10 mM Tris pH 8.0. The strands of the specific probe were: 5-ATT ACC CAC GTG TCC T*AC-3 and 5-GTA GGA CAC GTG GGT* AAT-3 (with the E-box sequence underlined) and the non-specific probe: 5-ATT ACC TCC GGA TCC T*AC-3 and 5-GTA GGA TCC GGA GGT* AAT-3 (Integrated DNA Technologies). Samples were further incubated for 10 minutes at room temperature and transferred to a 1 mm path length quartz cuvette. All spectra were recorded from 250 to 195 nm at 0.1 nm intervals by accumulating 10 spectra at 25 {degrees}C. Thermal denaturations were recorded at 222 nm from 5 to 95 {degrees}C at a heating rate of 1 {degrees}C/min. CD signal for spectra and thermal denaturations was corrected by substracting the signal from corresponding spectra or thermal denaturation either for buffer alone or the appropriate DNA duplex. CD signal was then converted to mean residue ellipticity using the following formula [5]: [{theta}] = {delta} {middle dot} MRW/(10{middle dot}c l) where [{theta}] is the mean residue ellipticity in deg {middle dot} cm2 dmol-1, {delta} is the CD signal in millidegrees, MRW is the mean residue weight, c is the concentration in mg/ml and l is the pathlength in mm. For the heterodimers, the concentration used was the sum of Max* and Myc* and the MRW was determined using a weighted average.

Aim and ObjectivesThe study aimed to evaluate the effectiveness of titanium inserts for interdental papilla reconstruction, comparing it with the Han and Takei technique using subepithelial connective tissue grafts. The objectives included assessing the black triangle height, papilla height and papilla presence index (PPI) at baseline, 1 month and 3 months postoperatively along with the evaluation of Early Wound Healing Score (EHS) during the first week of post operative healing period. Patients and MethodsThis single-blind randomized clinical trial included systemically healthy individuals aged 18-35 years with Nordland and Tarnows Class I-III papillary loss. A total of 18 participants were randomly assigned to either test group or control group. Clinical parameters were measured pre- and post-operatively at specified intervals. Both groups received standard presurgical care and postoperative follow-up. The surgical protocol for the test group involved titanium insert placement in the interdental bone, while the control group received a connective tissue graft using the Han and Takei method. ResultsBoth groups showed significant intragroup improvements in all parameters from baseline to 1 and 3 months (p<0.05). However, intergroup comparisons showed no significant differences at most time points, except at 3 months for PPI, where the control group showed significantly better results (p=0.04). EHS scores were not significant between the groups. ConclusionTitanium inserts and CTG both demonstrated clinical effectiveness in enhancing interdental papilla dimensions. These findings support the titanium insert as a viable, less invasive alternative, offering clinicians a practical option for esthetic papilla reconstruction.

BackgroundConventional clinical indicators of periodontitis progression detect disease after irreversible tissue destruction has occurred. Molecular biomarkers in gingival crevicular fluid (GCF) offer potential for earlier detection, but existing analytical approaches rely on cross-sectional snapshots that fail to capture the temporal dynamics of disease evolution. AimTo develop and validate a temporal deep learning framework leveraging longitudinal GCF protein profiles for (1) regression-based prediction of clinical attachment level (CAL) and probing depth (PD) changes, (2) current-visit classification of periodontitis progression, (3) next-visit prediction of progression with a 2-month clinical lead time, and (4) identification of the most informative biomarkers through systematic multi-method feature importance analysis. Materials and MethodsThis study utilized longitudinal GCF data from a prospective cohort of 413 participants (501 periodontal sites, 3,792 time-series observations) with 64 protein biomarkers measured at 2-month intervals over 12 months. A compact encoder-gated recurrent unit (GRU)-decoder architecture was developed through systematic experimentation across four phases, benchmarking temporal deep learning against cross-sectional machine learning baselines. Task-specific decoders addressed continuous regression (CAL and PD prediction) and binary classification (progression detection). Model development and reporting followed the TRIPOD+AI guidelines. ResultsThe temporal GRU achieved 47.7% CAL mean absolute error (MAE) reduction (1.139 to 0.596 mm) and 41.0% PD MAE reduction (0.902 to 0.532 mm) over linear regression baselines through the systematic model development progression. For binary classification, the model achieved AUC-ROC of 0.886 for current-visit classification and 0.867 for next-visit prediction with a 2-month lead time. Per-visit analysis revealed progressive improvement in both regression and classification accuracy as longitudinal data accumulated. Cross-method feature importance analysis identified Periostin, VEGF, MMP-2, IL-1RA, and MCP-4 as core predictive biomarkers, with divergent profiles between diagnostic and prognostic tasks suggesting distinct molecular signatures for concurrent versus incipient progression. ConclusionsTemporal deep learning applied to longitudinal GCF protein profiles enables both accurate regression prediction of clinical parameters and reliable classification of progression status, including 2-month-ahead forecasting suitable for clinical intervention planning. The compact architecture and non-invasive sampling approach make this framework suitable for integration into point-of-care periodontal monitoring workflows. Clinical RelevanceConventional clinical indicators of periodontitis progression, including probing depth changes, attachment loss, and radiographic bone loss, inherently detect disease after irreversible damage has occurred. This study shows that a compact deep learning model analyzing temporal GCF protein profiles can first accurately predict continuous changes in pocket depth and attachment loss, then classify progression status 2 months in advance, enabling proactive intervention before clinical manifestation of tissue destruction.

Variants in ACTB gene encoding for cytoplasmic {beta}-actin result in a group of rare disorders called non-muscle actinopathies (NMA). We investigated the cellular effects of a missense variant, G302A, and a four-amino-acid deletion, S338-I341, associated with the subgroup of NMA - ACTB pLoF (predicted loss-of-function) disorder in patient-derived fibroblast cells. We found that neither of the mutations affected the organization of actin or the width of the actin-filament bundles, while the mutation G302A reduced the stiffness of the cells as measured by using atomic force microscopy. The latter effect might be associated with the misorganization of tubulin and with the increased size and number of focal adhesions. When we challenged the cells by monolayer stretching and followed the mechanically-induced reorganization of the actin cytoskeleton, we found that G302A mutant cells showed more dense actin filament bundles within the cells compared to wild type cells. At the same time, the extent of cofilin reorganization from the cell periphery was increased upon stretch, and this correlated with an increased cofilin phosphorylation. In the case of the deletion, while the extent of cofilin phosphorylation increased, the extent of reorganization was unaltered; rather, the phosphorylation of myosin light chain, important in counteracting external force, was drastically reduced. We could partially rescue this fascinating effect by overexpressing the active form of the formin mDia. Our findings open the possibility to validate the cellular phenotype in the most affected patients cells, in neurons.

This study investigates the therapeutic potential of secretomes derived from Adipose-derived Mesenchymal Stem Cells (ADMSC-CM) and Limbal-derived Mesenchymal Stem Cells (LMSC-CM) against oxidative stress-induced damage in Retinal Pigment Epithelium (RPE-1) cells. RPE dysfunction, often triggered by oxidative stress, is a hallmark of various retinal degenerations. Here, we induced RPE-1 injury using H2O2 and evaluated the restorative effects of both MSC-conditioned media (CM). Our results demonstrated that both ADMSC-CM and LMSC-CM significantly enhanced cell viability and successfully reversed H2O2-induced G2/M phase cell cycle arrest. While oxidative stress triggered a pro-inflammatory response characterized by elevated IL-1{beta}, IL-6, and IL-10 expression, MSC-CM treatment, particularly ADMSC-CM, effectively modulated these levels and suppressed the p38 MAPK signaling pathway. Furthermore, MSC-CM reduced the Bax/Bcl-2 ratio, indicating an anti-apoptotic effect, and appeared to stabilize autophagic flux. To investigate the impact of oxidative-stress induced alterations in retinal pigment epithelial cells on angiogenesis, the effects of RPE-derived secreted factors on endothelial cell function were evaluated. Crucially, in terms of safety and secondary complications, neither secretome exhibited pro-angiogenic tendencies; instead, they significantly inhibited HUVEC migration and invasion compared to the H2O2 damaged group. These findings suggest that both ADMSC and LMSC secretomes provide a potent multi-targeted therapeutic effect, making them promising candidates for cell-free therapies in retinal diseases.

BackgroundDeep margin elevation (DME) is a restorative technique that facilitates the placement of restorations in cases of subgingival margins. Although clinically reported, very few data are available on dental practitioners awareness and use of DME. ObjectivesTo evaluate awareness and clinical acceptance toward deep margin elevation (DME) use in subgingival restorative cases among dental practitioners worldwide. MethodologyA cross-sectional questionnaire-based study was conducted among practicing dentists at various dental educational institutions, private dental practices, and a combination of academic and private dental practices across multiple centers globally. The self-administered questionnaire consisted of 20 closed-ended questions to evaluate awareness and clinical acceptance. The data were entered into and analyzed using a Chi-square test and descriptive statistics in the Statistical Package for the Social Sciences (SPSS) software. ResultsOut of 450 invited participants, 349 general dental practitioners completed the survey (77.6%). The purely educational institutions response rate was 79 (23%), the strictly private dental practice response rate was 134 (39%), and the combined academic and private practice response rate was 131 (38%). Sixty-six percent of respondents agreed that predictable adhesive bonding to cervical/root dentin can be achieved in restorations with deep margins. Although a majority of respondents had heard of DME (77%), the majority reported a preference for surgical crown lengthening (75%) when favorable conditions were present. ConclusionThe study highlights moderate DME awareness among the study participants. The findings of this study revealed that the number of dentists who use the technique to restore large subgingival defects in posterior teeth with proximal caries is very small. Thus, it is recommended that dental practitioners introduce this technique in their dental clinics as an alternative to surgical crown lengthening. Although years of experience and a dentists rank may influence clinical decisions, an in-depth factorial analysis with a larger sample size is necessary.

BackgroundVaping and vitamin D deficiency impact blood coagulation and health. This study aimed to investigate the effects of vitamin D supplementation on coagulation predictors in female rats exposed to E-cigarette vaping. ObjectiveTo examine the effect of vaping alone and vaping with different VD doses on some coagulation predictors, lungs, liver, and kidney functions MethodsForty-two female Wistar rats were divided into six groups, including vaping and non-vaping with high (50,000 IU) and low (1000 IU) vitamin D doses. Blood samples and histopathological analyses were conducted after one and three months. Nicotine, cotinine, Interleukin-6 (IL-6), D-dimer, coagulation factor X (FX), thrombomodulin (TM), Alanine Transaminase (ALT), and Creatinine levels were analyzed. Additionally, histopathological analyses were conducted on the rats liver, kidney, and lung. ResultsExposing rats to vaping for one month caused a significant acute increase in D-dimer, FX, and TM levels to 4402.05 ng/mL {+/-} 785.15, 1.8687 g/mL {+/-} 0.3132, and 34.71 ng/mL {+/-} 8.42, respectively. However, after three months of exposure, those levels decreased significantly compared to the one-month levels. Supplementation of the vape-exposed rats with a high vitamin D dose reduced levels of IL-6, D-dimer, FX, and TM levels to become 93.285 pg/mL {+/-} 12.715, 439.95 ng/mL {+/-} 294.05, 0.647 g/mL, and 17.375 ng/mL {+/-} 3.895, respectively, at the end of the three months. Moreover, vaping rats supplemented with the low and high doses of vitamin D had significantly lower nicotine and cotinine levels than the EC group, with a p-value of <0.0001. The histopathological examination revealed that the rats lung had necrotic pneumonia when exposed to vaping without vitamin D treatment. Moreover, all vaping groups had an alveolar hemorrhage. Bacterial pneumonia was seen in the high-dose vitamin D vape-exposed group. However, the histopathological examination of the liver indicated no major differences between the groups. One month of vaping raised D-dimer, FX, and TM levels, which decreased after three months. High-dose vitamin D supplementation reduced IL-6, D-dimer, and FX levels while increasing TM levels after three months. Vaping rats receiving vitamin D had lower nicotine and cotinine levels. Histopathological findings showed necrotic pneumonia and alveolar hemorrhage in vaping rats, with bacterial pneumonia in the high-dose group. ConclusionVaping activates inflammatory and coagulation pathways, while high-dose vitamin D appears to mitigate inflammation and blood coagulation issues associated with vaping, potentially aiding in reducing nicotine dependence.

Cryopreservation is essential for long-term storage of biological tissues. Yet, surprisingly, the precise molecular impact of cryopreservation on tissue transcriptomes remains poorly defined. This study provides the first resource of whole-genome transcriptomic changes following cryopreservation. This study used bulk RNA sequencing to examine how preservation method (snap freezing or vitrification) affects transcriptomes in mouse cerebral cortex and hippocampus. This allowed us to separate cryoprotectant-specific changes from cold induced-changes via snap freezing. In a subset of genes, tissues processed under vitrification conditions showed selective under-representation of a small but structurally coherent group of transcripts, with the hippocampus exhibiting greater vulnerability than the cortex. UniProt annotation revealed that affected transcripts were strongly enriched for proteins with membrane-associated, secretory-pathway, and multi-pass topologies, indicating that structurally complex membrane-integrated architectures are disproportionately sensitive to vitrification. Pathway-level analysis using iPANDA further showed that negative preservation scores in vitrified tissue clustered primarily within signal transduction and metabolic pathways, suggesting coordinated pathway-level disruption rather than global transcript loss. Together, these results demonstrate that vitrification conditions induce selective and structured molecular perturbations in neural tissue, defined by the under-recovery of transcripts associated with membrane and secretory pathway organization. This work highlights molecular vulnerability during vitrification and emphasizes the need for transcript-level evaluation when optimizing cryopreservation approaches for neural systems.

Ribosomal proteins, because of their RNA-binding capacity, may engage various cellular RNAs and fulfill nonribosomal roles. Previously, we and others described the intergenic regulation mediated by splicing of RPL22 paralogs in Saccharomyces cerevisiae. Here, we prepared a panel of RPL22A/B intronic mutants with respect to their RNAfold-predicted features and analyzed their properties. We tested the splicing and Rpl22-intron interaction using an intron-containing reporter and a three-hybrid yeast system, respectively. We found that the splicing of RPL22 introns can be inhibited by stabilizing a predicted stem as part of a particular type of conformation (I structure). Stabilizing the formation of an alternate stem (P structure) led to a permissive outcome of splicing. Intriguingly, the regulatory capacity of the main stem loop of the I structure was dependent on the rest of the intronic structure. Rpl22 enhanced splicing inhibition in WT and several of the mutants, which we interpret as stabilization of the I structure by protein binding. Mutagenesis identified both the main and alternative 5ss and additional stem loops as part of the regulatory mechanism. The inhibitory conformation of the intron did not prevent recognition of the 5ss and branch point, but rather stalled splicing at a later stage, before the first catalytic step. We concluded that the structural ensemble of the RPL22 pre-mRNA behaves as an allosteric switch that responds to [Rpl22].

Pentosan polysulfate (PPS) is a semisynthetic sulfated polysaccharide that was approved by the United States Food and Drug Administration (FDA) for treatment of interstitial cystitis (IC). A 2018 study by our group described a vision-threatening macular toxicity associated with long-term use of PPS. However, given the relatively recent characterization of PPS maculopathy, we have limited knowledge of its pathophysiology. The present study therefore investigated the pathophysiology of PPS maculopathy in a cell culture model, assessing impacts of PPS exposure on morphology and mitochondrial function. We treated ARPE-19 cells with increasing doses of PPS and investigated both mitoprotective and cytoprotective mechanisms, mitochondrial reactive oxygen species production (ROS) and respiration, cellular structure, and retinal pigment epithelium (RPE) dysfunction through phagocytosis assays. We found that PPS increased mitochondrial superoxide accumulation and that increased doses of PPS impaired basal and maximal respiration in a Seahorse assay without the expected response of increases in the cellular energy sensor pAMPK. PPS exposure disrupted mitochondrial and cell protective mechanisms against ROS accumulation as assessed through examination of mitochondrial biogenesis markers PGC-1 and SIRT1 and autophagy markers LC3 and p62. PINK1 expression increased with increasing duration of exposure to PPS. Further, we found that PPS led to functional and structural changes to RPE cells, which exhibited an increase in cell aspect ratio and impaired phagocytosis with higher doses of PPS. Lastly, we found an increase in cell death in response to higher doses of PPS, evident through ethidium homodimer cell viability assays. Taken together, our study shows PPS exposure has profound effects on RPE viability and function through impairment of mitochondrial respiration and mito- and cyto-protective mechanisms and highlights mitochondrial insult as a potential focus of future PPS research.

Saliva offers a noninvasive, lowcost, and patientfriendly matrix for biomarker discovery. Affinitybased proteomic technologies such as the Proximity Extension Assay (PEA) are increasingly being adopted for largescale biomarker studies, yet they remain underexplored in saliva. This study applied the Olink Explore HighThroughput (HT) PEA platform to profile approximately 5,400 proteins in saliva samples collected from donors representing periodontal health, gingivitis, advanced periodontitis (baseline and 3months posttreatment), and edentulism. Saliva from 68 donors was analysed, and all samples passed Olinks qualitycontrol procedures, with only 17 of 5,416 assays failing. Fortyone percent of proteins were detected above the limit of detection, demonstrating substantial assay sensitivity in this biofluid. Principal component analysis revealed clear compositional differences between clinical groups, with posttreatment periodontitis samples clustering more closely with health than baseline disease. Pairwise group comparisons identified hundreds of differentially abundant proteins, with consistently more proteins increased than decreased relative to health. This study demonstrates, for the first time, that Olink HT can robustly measure thousands of proteins in saliva with high data quality and biologically meaningful discrimination between periodontal states. The platforms minimal samplevolume requirements and scalability present strong potential for future salivabased biomarker discovery and translational research.

Aiming to examine the effect of chronic alcohol exposure on the activity of CYP3A enzymes in human liver, we studied the metabolism of two CYP3A-specific substrates, 7-benzyloxyquinoline (7-BQ) and ivermectin, in 23 preparations of human liver microsomes (HLM) obtained from donors with documented alcohol exposure, grading from non-drinkers to heavy alcoholics. All HLM samples were characterized for the composition of the cytochrome P450 pool and the abundances of other drug-metabolizing and endoplasmic reticulum-stress-related enzymes by global proteomics. Our studies revealed a striking increase in the activities of CYP3A enzymes caused by chronic alcohol exposure. This effect is not associated with changes in CYP3A enzyme levels, which do not correlate with alcohol exposure. Instead, the rates of 7-BQ and ivermectin metabolism correlate with the content of alcohol-inducible CYP2E1. However, this enzyme does not metabolize ivermectin, and its activity with 7-BQ is negligible. These results suggest that the observed acceleration of the elimination of drugs metabolized by CYP3A enzymes by alcohol exposure is due to functional effects of the interaction between CYP3A and CYP2E1. To elucidate the potential mechanism of this effect, we studied the formation of CYP2E1-CYP3A4 complexes in CYP3A4-containing Supersomes with co-incorporated CYP2E1 using tag-transfer chemical crosslinking mass spectrometry (CX-MS). These experiments confirmed physical interactions between the proteins and allowed the identification of CYP3A4 residues at the sites of contact. This information was used to build structural models of the CYP2E1-CYP3A4 complex and to propose possible mechanisms for the observed effects.

Parkinsons disease (PD) is the second most common neurodegenerative disease, resulting from accumulation of -synuclein (-syn) in midbrain dopaminergic neurons and progressive neuronal loss. The most relevant species of -syn, oligomers, may exert neurotoxicity in a variety of mechanisms. Accumulation of misfolded -syn in the endoplasmic reticulum (ER) lumen induces ER stress conditions that leads to activation of the Unfolded Protein Response (UPR) and its main sensor PKR-like ER kinase (PERK). PERK is critical for cell fate determination - under prolonged ER stress, it may direct cell towards pro-apoptotic pathways. Targeting of -syn aggregation or UPR by genetic and pharmacological approaches proved effective in preclinical models of PD by previous research. Thus, in the present study, we aimed to determine the potential effect of combination of small-molecule inhibitors of -syn aggregation and ER stress-mediated PERK signaling (namely anle138b and AMG44) in a novel, 3D in vitro model of PD. We demonstrate that combination of both anti-aggregation and ER stress-targeting approaches amplifies neuroprotection against PD in organoid model in terms of increased neuronal metabolic activity, decreased -syn phosphorylation and aggregation, reduced dopaminergic cell death, and restoration of proteostasis.

It has been recognized a long time ago that the hedgehog (Hh) and Wnt signaling pathways have numerous similarities that suggest their common evolutionary origin. Although the Hh and Wnt proteins are unrelated they are similar in as much as they carry lipid modifications that are critical for their interaction with their receptors. In our earlier work we have shown that Wnt inhibitory factor 1 (WIF1), originally identified as a Wnt antagonist also binds to and inhibits the signaling activity of sonic hedgehog (Shh), raising the possibility that the lipid moieties of these unrelated morphogens play a dominant role in their interaction with WIF1. In the present work we have compared the interactions of human WIF1 protein with lipidated and non-lipidated forms of human sonic hedgehog (Shh) using Surface Plasmon Resonance spectroscopy and reporter assays monitoring the signaling activity of human Shh. Our studies have shown that human WIF1 protein has significantly higher affinity for lipidated than non-lipidated Shh, indicating that lipid modifications of Hhs are important for interactions with WIF1.

This study aimed to examine whether Humanin-G (HNG), a mitochondrial derived peptide with cytoprotective properties, could improve the retinal function and gene expression profiles after intraperitoneal injections to Royal College of Surgeons (RCS) rats with Retinal Pigment Epithelium (RPE) dysfunction and retinal degeneration. Starting at postnatal day 21 (p21), RCS rats received twice a week intraperitoneal injections of either Low Dose HNG (0.4 mg/kg), High Dose HNG (4mg/kg), or sham-saline for 1 or 4 weeks. Visual function was tested with full field scotopic & photopic electroretinography (ERG) and optokinetic testing (OKT) 1 and 4 weeks after first injection (WAFI). The rats were euthanized after the ERG and OKT (1 or 4 WAFI) and the dissected retinas and RPE were collected for RNA, cDNA and Quantitative Real-time PCR (qRT-PCR) analysis. The results of our study showed that high dose (4mg/kg) HNG at 4 WAFI was associated with the largest change in gene expression in the RPE and retina of treated animals, altering expression of genes involved in apoptosis, oxidative stress, inflammation and retinal/RPE function. Analysis of a and b waves from scotopic and photopic ERG showed no difference between either low or high dose of HNG and sham injection at 4 WAFI. However, at 4 WAFI, the visual acuity in rats treated with high dose HNG showed significant improvement as compared to the rats treated with low dose of HNG or saline. Most significantly, our findings support that HNG administered IP can modulate RPE/neuroretina cells and improve vision, thus may be a potential treatment for retinal degeneration diseases.

1.Functional neuronal circuits in the vertebrate retina emerge through coordinated developmental events, yet the timeline by which bipolar cells acquire visual feature selectivity remains unclear. A major barrier is the limited genetic access to bipolar subtypes during early postnatal stages. Recent comprehensive transcriptomic study points to Igfn1 as a molecular marker for type-7 bipolar cells (BC 7), a subtype that exhibits direction-selective glutamate releases in adult. Here, we generated an Igfn1iCre knock-in mouse line and characterized Igfn1-positive cell morphology from postnatal day 4(P4) to adult using Cre-dependent tdTomato reporter mice. We found Igfn1-positive cells in the inner retina by P12-P15, predominantly labelling bipolar cells and some amacrine populations. At P15, about 71% of labelled bipolar cells stratified their axons in the S4 sublamina of the inner plexiform layer, consistent with BC 7 morphology. In adult retina, the widespread Igfn1-labelling appears slightly dominated in amacrine cells. To validate these observations, we analysed Igfn1 expression in the Mouse Retina Cell Atlas and confirmed strong Igfn1 enrichment in BC 7 and expression in additional retinal cell types, mirroring experimental results. Overall, these results reveal Igfn1iCre as a potential developmental tool for BC 7 access in the retina.

AO_SCPLOWBSTRACTC_SCPLOWThe cellular transcription factor BCL11b (B-cell CLL/lymphoma 11b) interacts with numerous cellular and viral factors to modulate gene expression positively or negatively. Post-translational modifications of BCL11b, such as SUMOylation and phosphorylation, have been documented to switch its transcriptional activity from a repressor to an activator state. In the present study, we investigated the acetylation of BCL11b and we identified the histone acetyltransferase p300 as able to acetylate BCL11b. Subsequently, we observed that the mutation of the lysine K686 residue of BCL11b (BCL11b K686R) influenced its global acetylation. Furthermore, the BCL11b K686R mutation also modulated the transcriptional regulation of BCL11b, including its activity in regulating the p21 and IL-2 promoters. This effect on transcriptional regulation was due to the importance of the lysine K686 residue for BCL11b nuclear localization. Our results underscore the critical role of the lysine K686 residue in BCL11b for its interaction with p300 and its nuclear localization, suggesting a possible function of p300 in the nuclear transport of BCL11b. Collectively, our findings contribute to a better understanding of BCL11b-mediated gene expression and of the interactions of BCL11b with cellular partners.

Long non-coding RNAs (lncRNAs) account for a major proportion of the transcriptional output in complex organismal genomes. Their emergence as auxiliary regulators of gene expression as well as their roles in metastasis and cancer progression has put them in the limelight. LncRNAs perform multitudes of functions and often moonlight as regulators, scaffolds and guides. Most lncRNAs are cell and tissue specific and can act as markers for diseases as well as targets for therapeutic interventions. LncRNAs are also known to make use of higher order structures such as G-quadruplexes (G4) to facilitate complex functions and interactions. THAP9-antisense1 (AS1) is a lncRNA coding gene (recently annotated by Ensembl) that codes for 12 lncRNA transcripts and has been implicated in many disease pathologies like gastric cancer, spontaneous neutrophil apoptosis, hepatocellular carcinoma, and the progression of oesophageal cancer. It is the antisense gene pair of the THAP9 gene ( a transposase derived gene) with which it shares a promoter. THAP9-AS1 has been reported to be dysregulated during stress and several cancers. However, the exact role of the lncRNA is not well understood. Bioinformatics driven strategies are used to identify putative quadruplex forming sequences (PQSs) within the lncRNA THAP9-AS1. The identified PQSs are further validated using biophysical, spectroscopic and molecular biology driven techniques. The importance of each G-tract in the formation of a particular RNA G-quadruplex (rG4) is studied via the investigation of several deletion mutants. The findings demonstrate the rG4 forming potential of the identified PQSs within THAP9-AS1.