With exercise, muscle and bone produce factors with beneficial effects on brain, fat, and other organs. Exercise in mice increased fibroblast growth factor 23 (FGF23), urine phosphate, and the muscle metabolite L-β-aminoisobutyric acid (L-BAIBA), suggesting that L-BAIBA may play a role in phosphate metabolism. Here, we show that L-BAIBA increases in serum with exercise and elevates Fgf23 in osteocytes. The D enantiomer, described to be elevated with exercise in humans, can also induce Fgf23 but through a delayed, indirect process via sclerostin. The two enantiomers both signal through the same receptor, Mas-related G-protein-coupled receptor type D, but activate distinct signaling pathways; L-BAIBA increases Fgf23 through Gαs/cAMP/PKA/CBP/β-catenin and Gαq/PKC/CREB, whereas D-BAIBA increases Fgf23 indirectly through sclerostin via Gαi/NF-κB. In vivo, both enantiomers increased Fgf23 in bone in parallel with elevated urinary phosphate excretion. Thus, exercise-induced increases in BAIBA and FGF23 work together to maintain phosphate homeostasis.

Hyperalgesia is typified by reduced pain thresholds and heightened responses to painful stimuli, with a notable prevalence in menopausal women, but the underlying mechanisms are far from understood. β-Aminoisobutyric acid (BAIBA), a product of valine and thymine catabolism, has been reported to be a novel ligand of the Mas-related G protein coupled receptor D (MrgprD), which mediates pain and hyperalgesia. Here, we established a hyperalgesia model in 8-week-old female mice through ovariectomy (OVX). A significant increase in BAIBA plasma level was observed and was associated with decline of mechanical withdrawal threshold, thermal and cold withdrawal latency in mice after 6 weeks of OVX surgery. Increased expression of MrgprD in dorsal root ganglion (DRG) was shown in OVX mice compared to Sham mice. Interestingly, chronic loading with BAIBA not only exacerbated hyperalgesia in OVX mice, but also induced hyperalgesia in gonadally intact female mice. BAIBA supplementation also upregulated the MrgprD expression in DRG of both OVX and intact female mice, and enhanced the excitability of DRG neurons in vitro. Knockout of MrgprD markedly suppressed the effects of BAIBA on hyperalgesia and excitability of DRG neurons. Collectively, our data suggest the involvement of BAIBA in the development of hyperalgesia via MrgprD-dependent pathway, and illuminate the mechanisms underlying hyperalgesia in menopausal women.

Natural membrane receptors are proteins that can report on changes in the concentration of external chemical messengers. Messenger binding to a receptor produces conformational changes that are relayed through the membrane into the cell; this information allows cells to adapt to changes in their environment. Artificial membrane receptors (R)-1 and (S)-1 are helical α-aminoisobutyric acid (Aib) foldamers that replicate key parts of this information relay. Solution-phase 19F NMR spectroscopy of zinc(II)-capped receptor 1, either in organic solvent or in membrane-mimetic micelles, showed messenger binding produced an enrichment of either left- or right-handed screw-sense; the chirality of the bound messenger was relayed to the other receptor terminus. Furthermore, in situ production of a chemical messenger in the external aqueous environment could be detected in real-time by a racemic mixture of receptor 1 in micelles. The hydrolysis of insoluble anhydrides produced carboxylate in the aqueous phase, which bound to the receptors and gave a distinct 19F NMR output from inside the hydrophobic region of the micelles.

Access to Hepatis C treatment in Sub-Saharan Africa is a clinical, public health and ethical concern. The multi-country open-label trial TAC ANRS 12311 allowed assessing the feasibility, safety, efficacy of a specific care model of HCV treatment and retreatment in patients with hepatitis C in Sub Saharan Africa. Between November 2015 and March 2017, with follow-up until mid 2019, treatment-naïve patients with HCV without decompensated cirrhosis or liver cancer were recruited to receive 12 week-treatment with either sofosbuvir + ribavirin (HCV genotype 2) or sofosbuvir + ledipasvir (genotype 1 or 4) and retreatment with sofosbuvir + velpatasvir + voxilaprevir in case of virological failure. The primary outcome was sustained virological response at 12 weeks after end of treatment (SVR12). Secondary outcomes included treatment adherence, safety and SVR12 in patients who were retreated due to non-response to first-line treatment. The model of care relied on both viral load assessment and educational sessions to increase patient awareness, adherence and health literacy. The study recruited 120 participants, 36 HIV-co-infected, and 14 cirrhotic. Only one patient discontinued treatment because of return to home country. Neither death nor severe adverse event occurred. SVR12 was reached in 107 patients (89%): (90%) in genotype 1 or 2, and 88% in GT-4. All retreated patients (n = 13) reached SVR12. HCV treatment is highly acceptable, safe and effective under this model of care. Implementation research is now needed to scale up point-of-care HCV testing and SVR assessment, along with community involvement in patient education, to achieve HCV elimination in Sub-Saharan Africa.

Sofosbuvir, velpatasvir and voxilaprevir (SOF/VEL/VOX) is the recommended rescue therapy for patients with chronic hepatitis C infection who fail direct-acting antivirals (DAAs). Data are limited on the effectiveness of this treatment after the current first-line therapies. Our aim was to analyse the effectiveness and safety of SOF/VEL/VOX among patients failing sofosbuvir/velpatasvir (SOF/VEL) or glecaprevir/pibrentasvir (GLE/PIB).
Retrospective multicentre study (26 Spanish hospitals), including chronic hepatitis C patients unsuccessfully treated with SOF/VEL or GLE/PIB, and retreated with SOF/VEL/VOX ± ribavirin for 12 weeks between December 2017 and December 2022.
In total, 142 patients included: 100 (70.4%) had failed SOF/VEL and 42 (29.6%) GLE/PIB. Patients were mainly men (84.5%), White (93.9%), with hepatitis C virus genotype (GT) 3 (49.6%) and 47.2% had liver cirrhosis. Sustained virological response (SVR) was evaluated in 132 patients who completed SOF/VEL/VOX and were followed 12 weeks after end of treatment; 117 (88.6%) achieved SVR. There were no significant differences in SVR rates according to initial DAA treatment (SOF/VEL 87.9% vs. GLE/PIB 90.2%, p = 0.8), cirrhosis (no cirrhosis 90% vs. cirrhosis 87.1%, p = 0.6) or GT3 infection (non-GT3 91.9% vs. GT3 85.5%, p = 0.3). However, when considering the concurrent presence of SOF/VEL treatment, cirrhosis and GT3 infection, SVR rates dropped to 82.8%. Ribavirin was added in 8 (6%) patients, all achieved SVR.
SOF/VEL/VOX is an effective rescue therapy for failures to SOF/VEL or GLE/PIB, with an SVR of 88.6%. Factors previously linked to lower SVR rates, such as GT3 infection, cirrhosis and first-line therapy with SOF/VEL were not associated with lower SVRs.

Glecaprevir/pibrentasvir (GLE/PIB) is an approved guideline-recommended chronic hepatitis C virus infection treatment. GLE/PIB coadministration with ethinyl oestradiol (EE) is not recommended in current labels owing to a Phase 1 study observing Grade ≥2 alanine aminotransferase (ALT) elevation in 2 out of 12 healthy women cotreated for 11 days with GLE/PIB and oral contraceptive (OC) containing 35 μg/250 μg EE/norgestimate. No Grade ≥2 elevation was observed with low-dose (20 μg) EE (n = 14). This Phase 1 study examined safety/tolerability of GLE/PIB coadministered with an OC containing low-dose EE using a larger sample size and longer treatment duration. Healthy premenopausal women were treated with EE/levonorgestrel alone (20/100 μg, Cycles 1-2), followed by coadministration with GLE/PIB (300/120 mg; Cycles 3-4). A safety criterion of special interest was a confirmed Grade ≥2 ALT elevation (>3× upper normal limit). Adverse events (AEs) and study drugs concentrations were examined. Of 85 enrolled women, 72 initiated combined GLE/PIB + EE/levonorgestrel treatment, 66 completed the study and 19 discontinued prematurely (non-safety reason, n = 16; AE [deemed unelated to GLE/PIB], n = 3). No participant met the safety criterion of special interest of confirmed Grade ≥2 ALT elevation. No serious/Grade ≥3 AEs were reported. Study drug concentrations were within the expected ranges. GLE/PIB in combination with an OC containing low-dose EE was generally well tolerated with no confirmed Grade ≥2 ALT elevation and no evidence of drug-induced liver injury. No pattern to the reported AEs and no new safety issues were identified. This was a Phase 1 study of healthy volunteers, not a registered clinical trial.

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The fibrillation of therapeutic peptides can present significant quality concerns and poses challenges for manufacturing and storage. A fundamental understanding of the mechanisms of fibrillation is critical for the rational design of fibrillation-resistant peptide drugs and can accelerate product development by guiding the selection of solution-stable candidates and formulations. The studies reported here investigated the effects of structural modifications on the fibrillation of a 29-residue peptide (PepA) and two sequence modified variants (PepB, PepC). The C-terminus of PepA was amidated, whereas both PepB and PepC retained the carboxylate, and Ser16 in PepA and PepB was substituted with a helix-stabilizing residue, α-aminoisobutyric acid (Aib), in PepC. In thermal denaturation studies by far-UV CD spectroscopy and fibrillation kinetic studies by fluorescence and turbidity measurements, PepA and PepB showed heat-induced conformational changes and were found to form fibrils, whereas PepC did not fibrillate and showed only minor changes in the CD signal. Pulsed hydrogen-deuterium exchange mass spectrometry (HDX-MS) showed a high degree of protection from HD exchange in mature PepA fibrils and its proteolytic fragments, indicating that most of the sequence had been incorporated into the fibril structure and occurred nearly simultaneously throughout the sequence. The effects of the net peptide charge and formulation pH on fibrillation kinetics were investigated. In real-time stability studies of two formulations of PepA at pH\'s 7.4 and 8.0, analytical methods detected significant changes in the stability of the formulations at different time points during the study, which were not observed during accelerated studies. Additionally, PepA samples were withdrawn from real-time stability and subjected to additional stress (40 °C, continuous shaking) to induce fibrillation; an approach that successfully amplified oligomers or prefibrillar species previously undetected in a thioflavin T assay. Taken together, these studies present an approach to differentiate and characterize fibrillation risk in structurally related peptides under accelerated and real-time conditions, providing a model for rapid, iterative structural design to optimize the stability of therapeutic peptides.

Bergofungin D is a helical peptide of the peptaibol family consisting of 14 amino acids, six of which are the helix inducer aminoisobutyric acid (Aib). In the second third of the sequence, a hydroxyproline causes a bending of the helix and a disruption of the hydrogen bond network, and Aib7 is the only amino acid in this region involved in the hydrogen bond network. Therefore, modification of this residue can serve as a probe to monitor the effect of introducing amino acid substitutions on this more fragile helical turn. To validate this approach, we simplified the original bergofungin D by reducing the number of non-classical amino acids, replacing the (R)-isovaleric acid by its enantiomer or an Aib and the hydroxyproline with a proline, respectively, without affecting its secondary structure. Within the modified structure, we replaced Aib7-Aib8 by its 1,2,3-triazolodipeptide equivalent or Aib7 by a serine or a dehydrobutyrine. We have reported and analyzed five crystal structures, three of which are new, demonstrating the usefulness of the modified bergofungin D as a probe for monitoring the introduction of amino acid substitutions within a helical structure.

UNASSIGNED: This study compared the effectiveness and safety of glecaprevir/pibrentasvir (GLE/PIB) and sofosbuvir/ledipasvir (SOF/LDV) in real-life clinical practice.
UNASSIGNED: The data from genotype 1 or 2 chronic hepatitis C patients treated with GLE/PIB or sofosbuvir + ribavirin or SOF/LDV in South Korea were collected retrospectively. The analysis included the treatment completion rate, sustained virologic response at 12 weeks (SVR12) test rate, treatment effectiveness, and adverse events.
UNASSIGNED: Seven hundred and eighty-two patients with genotype 1 or 2 chronic hepatitis C who were treated with GLE/PIB (n=575) or SOF/LDV (n=207) were included in this retrospective study. The baseline demographic and clinical characteristics revealed significant statistical differences in age, genotype, ascites, liver cirrhosis, and hepatocellular carcinoma between the GLE/PIB and SOF/LDV groups. Twenty-two patients did not complete the treatment protocol. The treatment completion rate was high for both regimens without statistical significance (97.7% vs. 95.7%, p=0.08). The overall SVR12 of intention-to-treat analysis was 81.2% vs. 80.7% without statistical significance (p=0.87). The overall SVR12 of per protocol analysis was 98.7% vs. 100% without statistical significance (p=0.14). Six patients treated with GLE/PIB experienced treatment failure. They were all male, genotype 2, and showed a negative hepatitis C virus RNA level at the end of treatment. Two patients treated with GLE/PIB stopped medication because of fever and abdominal discomfort.
UNASSIGNED: Both regimens had similar treatment completion rates, effectiveness, and safety profiles. Therefore, the SOF/LDV regimen can also be considered a viable DAA for the treatment of patients with genotype 1 or 2 chronic hepatitis C.