Accurate Prediction of Enzyme Thermostabilization with Rosetta Using AlphaFold Ensembles.

Thermostability enhancement is a fundamental aspect of protein engineering as a biocatalyst's half-life is key for its industrial and biotechnological application, particularly at high temperatures and under harsh conditions. Thermostability changes upon mutation originate from modifications of the free energy of unfolding (ΔGu), making thermostabilization extremely challenging to predict with computational methods. In this contribution, we combine global conformational sampling with energy prediction using AlphaFold and Rosetta to develop a new computational protocol for the quantitative prediction of thermostability changes upon laboratory evolution of acyltransferase LovD and lipase LipA. We highlight how using an ensemble of protein conformations rather than a single three-dimensional model is mandatory for accurate thermostability predictions. By comparing our approaches with existing ones, we show that ensembles based on AlphaFold models provide more accurate and robust calculated thermostability trends than ensembles based solely on crystallographic structures as the latter introduce a strong distortion (scaffold bias) in computed thermostabilities. Eliminating this bias is critical for computer-guided enzyme design and evaluating the effect of multiple mutations on protein stability.

A pharmacogenetics study in Mozambican patients treated with nevirapine: full resequencing of TRAF3IP2 gene shows a novel association with SJS/TEN susceptibility.

Steven-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe adverse drug reactions, characterized by extensive epidermal detachment and erosions of mucous membrane. SJS/TEN is one of the most serious adverse reactions to Nevirapine (NVP) treatment, commonly used in developing countries as first-line treatment of human immunodeficiency virus infection. In the last years TRAF3IP2 gene variants had been described as associated with susceptibility to several diseases such as psoriasis and psoriatic arthritis. We hypothesized that this gene, involved in immune response and in NF-κB activation, could also be implicated in the SJS/TEN susceptibility. We performed a full resequencing of TRAF3IP2 gene in a population of patients treated with NVP. Twenty-seven patients with NVP-induced SJS/TEN and 78 controls, all from Mozambique, were enrolled. We identified eight exonic and three intronic already described variants. The case/control association analysis highlighted an association between the rs76228616 SNP in exon 2 and the SJS/TEN susceptibility. In particular, the variant allele (C) resulted significantly associated with a higher risk to develop SJS/TEN (p = 0.012 and OR = 3.65 (95% CI 1.33-10.01)). A multivariate analysis by logistic regression confirmed its significant contribution (p = 0.027, OR = 4.39 (95% CI 1.19-16.23)). In conclusion, our study suggests that a variant in TRAF3IP2 gene could be involved in susceptibility to SJS/TEN.

Pharmacogenetics of inflammatory bowel disease: a focus on Crohn's disease.

Crohn's disease is an inflammatory bowel disease showing a high heterogeneity in phenotype and a strong genetic component. The treatment is complex, due to different severity of clinical parameters and to the fact that therapies only permit to control symptoms and to induce remission for short periods. Moreover, all categories of drugs present a great interindividual variability both in terms of efficacy and side effects appearance. For this reason, the identification of specific genomic biomarkers involved in drugs response will be of great clinical utility in order to foresee drug's efficacy and to prevent adverse reactions, permitting a more personalized therapeutic approach. In this review, we focus the attention on the pharmacogenetic studies regarding drugs commonly utilized in Crohn's disease treatment.

Polymorphisms in STAT4, PTPN2, PSORS1C1 and TRAF3IP2 Genes Are Associated with the Response to TNF Inhibitors in Patients with Rheumatoid Arthritis.

OBJECTIVE: Rheumatoid Arthritis (RA) is a progressive autoimmune disease characterized by chronic joint inflammation and structural damage. Remission or at least low disease activity (LDA) represent potentially desirable goals of RA treatment. Single nucleotide polymorphisms (SNPs) in several genes might be useful for prediction of response to therapy. We aimed at exploring 4 SNPs in candidate genes (STAT4, PTPN2, PSORS1C1 and TRAF3IP2) in order to investigate their potential role in the response to therapy with tumor necrosis factor inhibitors (TNF-i) in RA patients. METHODS: In 171 RA patients we investigated the following SNPs: rs7574865 (STAT4), rs2233945 (PSORS1C1), rs7234029 (PTPN2) and rs33980500 (TRAF3IP2). Remission, LDA, and EULAR response were registered at 6 months and 2 years after initiation of first line TNF-i [Adalimumab (ADA) and Etanercept (ETN)]. RESULTS: STAT4 variant allele was associated with the absence of a good/moderate EULAR response at 2 years of treatment in the whole RA group and in ETN treated patients. The PTPN2 SNP was associated with no good/moderate EULAR response at 6 months in ADA treated patients. Patients carrying PSORS1C1 variant allele did not reach LDA at 6 months in both the whole RA group and ETN treated patients. TRAF3IP2 variant allele was associated with the lack of LDA and remission achievement at 6 months in all RA cohort while an association with no EULAR response at 2 years of treatment occurred only in ETN treated patients. CONCLUSIONS: For the first time, we reported that SNPs in STAT4, PTPN2, PSORS1C1, and TRAF3IP2 are associated with response to TNF-i treatment in RA patients; however, these findings should be validated in a larger population.

Stevens-Johnson syndrome and toxic epidermal necrolysis: an update on pharmacogenetics studies in drug-induced severe skin reaction.

Stevens-Johnson syndrome and toxic epidermal necrolysis are severe, life-threatening drug reactions involving skin and membranes mucous, which are associated with significant morbidity and mortality and triggered, especially by drug exposure. Different studies have demonstrated that drug response is a multifactorial character and that the interindividual variability in this response depends on both environmental and genetic factors. The last ones have a relevant significance. In fact, the identification of new specific genetic markers involved in the response to drugs, will be of great utility to establish a more personalized therapeutic approach and to prevent the appearance of these adverse reactions. In this review, we summarize recent progresses in the Pharmacogenetics studies related to Stevens-Johnson syndrome/toxic epidermal necrolysis reporting the major genetic factors identified in the last years as associated with the disease and highlighting the use of some of these genomic variants in the clinical practice.

Could MicroRNA polymorphisms influence warfarin dosing? A pharmacogenetics study on mir133 genes.

MicroRNAs are small single stranded molecules that play a crucial role in regulation of physiological and pathological processes. Recent studies showed that VKORC1 gene contains an highly evolutionary conserved binding site for mir-133. Moreover, in human hepatocytes mir-133 is constitutively co-expressed with VKORC1. Since VKORC1 protein is the target of warfarin treatment, the aim of this study was to verify if genetic variations in MIR133A1, MIR133A2 and MIR133B could contribute to warfarin dose variability. By direct sequencing, we identified 4 SNPs in MIR133A2 gene and 1 SNP in MIR133B gene. Three SNPs in MIR133A2 were in complete linkage disequilibrium and correlated with warfarin dose: indeed, for each SNP, patients carrying the GA or AA genotype required a MWWD significantly higher than the wildtype genotype (P=0.019). We also inferred the haplotypes in MIR133A2 gene. The GC haplotype required a MWWD significantly lower than AT haplotype (P=0.012). The multiple linear regression analysis confirmed that rs45547937 (as tag SNP) in MIR133A2 could be involved in warfarin dosing variability, (P=0.016). These results seem to suggest that also polymorphisms in miRNA precursors may potentially affects drug response variability.

Genetic Factors in Systemic Lupus Erythematosus: Contribution to Disease Phenotype.

Genetic factors exert an important role in determining Systemic Lupus Erythematosus (SLE) susceptibility, interplaying with environmental factors. Several genetic studies in various SLE populations have identified numerous susceptibility loci. From a clinical point of view, SLE is characterized by a great heterogeneity in terms of clinical and laboratory manifestations. As widely demonstrated, specific laboratory features are associated with clinical disease subset, with different severity degree. Similarly, in the last years, an association between specific phenotypes and genetic variants has been identified, allowing the possibility to elucidate different mechanisms and pathways accountable for disease manifestations. However, except for Lupus Nephritis (LN), no studies have been designed to identify the genetic variants associated with the development of different phenotypes. In this review, we will report data currently known about this specific association.

Autophagy and inflammatory bowel disease: Association between variants of the autophagy-related IRGM gene and susceptibility to Crohn's disease.

BACKGROUND: Crohn's disease and ulcerative colitis are inflammatory bowel diseases involving a genetically determined inappropriate mucosal immune response towards luminal antigens, including resident bacterial flora. Recent studies identified susceptibility genes involved in autophagy. AIMS: We analyzed known autophagic loci (IRGM, ULK1 and AMBRA1) previously described as associated with inflammatory bowel diseases or with other autoimmune and/or inflammatory disorders in a sample of Italian inflammatory bowel diseases patients in order to confirm their possible involvement and relative contribution in the disease. METHODS: We performed a case-control association study, a sub-phenotype correlation and a haplotype analysis. The analysis included 263 Crohn's disease, 206 ulcerative colitis patients and 245 matched healthy controls. Five polymorphisms were genotyped by allelic discrimination assays. RESULTS: IRGM was the most strongly associated with Crohn's disease susceptibility [rs13361189: P=0.011, OR=1.66 [95% CI: (1.12-2.45)]; rs4958847: P=0.05, OR=1.43 [95% CI: (1-2.03)]. The SNP rs13361189 was also found to increase the risk of Crohn's disease clinical sub-phenotype (fibrostricturing behaviour, ileal disease, perianal disease, intestinal resection). These findings suggest that IRGM variants may modulate clinical characteristics of Crohn's disease. CONCLUSIONS: Our study confirms IRGM rs13361189 and rs4958847 polymorphisms to be important for Crohn's disease susceptibility and phenotype modulation, in accordance with previous findings.

A multilocus genetic study in a cohort of Italian SLE patients confirms the association with STAT4 gene and describes a new association with HCP5 gene.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disease with complex pathogenesis in which genes and environmental factors are involved. We aimed at analyzing previously identified loci associated with SLE or with other autoimmune and/or inflammatory disorders (STAT4, IL10, IL23R, IRAK1, PSORS1C1, HCP5, MIR146a, PTPN2, ERAP1, ATG16L1, IRGM) in a sample of Italian SLE patients in order to verify or confirm their possible involvement and relative contribution in the disease. MATERIALS AND METHODS: Two hundred thirty-nine consecutive SLE patients and 278 matched healthy controls were enrolled. Study protocol included complete physical examination, and clinical and laboratory data collection. Nineteen polymorphisms were genotyped by allelic discrimination assays. A case-control association study and a genotype-phenotype correlation were performed. RESULTS: STAT4 was the most associated gene [P = 3 × 10(-7), OR = 2.13 (95% CI: 1.59-2.85)]. IL10 confirmed its association with SLE [rs3024505: P = 0.02, OR = 1.52 (95% CI: 1.07-2.16)]. We describe a novel significant association between HCP5 locus and SLE susceptibility [rs3099844: P = 0.01, OR = 2.06 (95% CI: 1.18-3.6)]. The genotype/phenotype correlation analysis showed several associations including a higher risk to develop pericarditis with STAT4, and an association between HCP5 rs3099844 and anti-Ro/SSA antibodies. CONCLUSIONS: STAT4 and IL10 confirm their association with SLE. We found that some SNPs in PSORS1C1, ATG16L1, IL23R, PTPN2 and MIR146a genes can determine particular disease phenotypes. HCP5 rs3099844 is associated with SLE and with anti-Ro/SSA. This polymorphism has been previously found associated with cardiac manifestations of SLE, a condition related with anti-Ro/SSA antibodies. Thus, our results may provide new insights into SLE pathogenesis.

Common polymorphisms in MIR146a, MIR128a and MIR27a genes contribute to neuropathy susceptibility in type 2 diabetes.

Diabetic polyneuropathy (DPN) and cardiovascular autonomic neuropathy (CAN) are common type 2 diabetes complications with a large inter-individual variability in terms of clinical manifestations and severity. Our aim was to evaluate a possible involvement of genetic polymorphisms in miRNA regions in the susceptibility to DPN and CAN. Nine polymorphisms in miRNA genes were studied in a sample of 132 type 2 diabetes patients (T2D) analysed for DPN and 128 T2D patients analysed for CAN. A genotype-phenotype correlation analysis was performed. The T allele of rs11888095 single nucleotide polymorphism (SNP) in MIR128a was significantly associated with a higher risk (ORadj = 4.89, P adj = 0.02), whereas the C allele of rs2910164 SNP in MIR146a was associated with a lower risk to develop DPN (ORadj = 0.49, P adj = 0.09), respectively. A multivariate logistic regression analysis confirmed that both SNPs contribute to DPN (p < 0.001 and p = 0.01 for MIR128a and MIR146a, respectively). MIR128a SNP significantly contributed also to DPN score (p = 0.026). Rs895819 SNP in MIR27a was significantly associated with a higher risk to develop early CAN (P adj = 0.023 and ORadj = 3.43). The rs2910164 SNP in MIR146a showed a protective effect respect to early CAN (P adj = 0.052, ORadj = 0.32) and to confirmed CAN (P adj = 0.041, ORadj = 0.13). The same SNP resulted significantly associated with a lower CAN score and a higher E/I (p = 0.002 and p = 0.003, respectively). In conclusion, we described associations of MIR128a and MIR146a SNPs with DPN susceptibility and of MIR146a and MIR27a SNPs with CAN susceptibility. This is the first study showing that genetic variability in miRNA genes could be involved in diabetic neuropathies susceptibility.

Resequencing of VKORC1, CYP2C9 and CYP4F2 genes in Italian patients requiring extreme low and high warfarin doses.

PURPOSE: The aim of the present study was to investigate the genetic variability of VKORC1, CYP2C9 and CYP4F2 genes in patients who required a very low and high warfarin dose, in order to identify novel variants that could help to explain the particular extreme dose requirements. METHODS: Among patients followed and treated with warfarin at the Center of Haemostasis and Thrombosis of the PTV, we selected twelve patients showing a high divergence from warfarin standard doses required to achieve the therapeutic effect. All VKORC1, CYP2C9 and CYP4F2 coding regions, 3' and 5' UTR and exon/intron boundaries were analyzed by direct sequencing. RESULTS: The 1173T and -1639A allele variants in VKORC1 gene, associated with warfarin sensitivity, were present, as expected, mostly in low dose patients while 3730A allele, linked to warfarin resistance, has been found only in high dose patients. Interestingly, we found that three out of six low dose subjects presented CYP2C9*3/*3 homozygous genotype, very rare in Caucasians. Besides these common polymorphisms, we identified 5 SNPs in CYP2C9 gene and 19 SNPs in CYP4F2 gene. Among these, all polymorphisms identified in CYP2C9 gene were present only in low dose patients and three of them resulted in linkage with CYP2C9*2 and CYP2C9*3. Regarding CYP4F2 SNPs, we did not observe differences between the high and low dose patients. At the end, the whole sequencing did not reveal any novel polymorphism/mutation. CONCLUSION: Further studies are required to identify other genetic factors contributing to extreme warfarin requirement.

MicroRNA genetic variations: association with type 2 diabetes.

MicroRNAs are small single-stranded molecules that have emerged as important genomic regulators in different pathways. Different studies have shown that they are implicated in the metabolism and glucose homeostasis, and therefore, they could also be involved in the pathogenesis of metabolic disorders such as type 2 diabetes (T2DM). The aim of this study was to verify whether genetic variations in candidate microRNA (miRNA or miR) genes could contribute to T2DM susceptibility. We have selected 13 miRNAs as candidate loci according to literature data and to a computational analysis. MicroRNA genes were analyzed by direct sequencing in a cohort of 163 Italian T2DM patients and 185 healthy controls. We identified 6 novel variants never described before and 9 SNPs already described in databases. Five newly identified variants were found only in the cases group. We performed a case/control association study to test the associations of particular alleles/genotypes of identified SNPs with the disease. Two polymorphisms were associated with T2DM susceptibility: in particular, the G allele of rs895819 in hsa-mir-27a has shown a significantly protective effect (OR = 0.58 and P = 0.008), while the G allele of rs531564 in hsa-mir-124a appears to be a risk allele (OR = 2.15, P = 0.008). This is the first report indicating that genetic polymorphisms in miRNA regions could contribute to T2DM susceptibility.