SARS-CoV-2 infects the human kidney and drives fibrosis in kidney organoids

Kidney failure is frequently observed during and after COVID-19, but it remains elusive whether this is a direct effect of the virus. Here, we report that SARS-CoV-2 directly infects kidney cells and is associated with increased tubule-interstitial kidney fibrosis in patient autopsy samples. To study direct effects of the virus on the kidney independent of systemic effects of COVID-19, we infected human-induced pluripotent stem-cell-derived kidney organoids with SARS-CoV-2. Single-cell RNA sequencing indicated injury and dedifferentiation of infected cells with activation of profibrotic signaling pathways. Importantly, SARS-CoV-2 infection also led to increased collagen 1 protein expression in organoids. A SARS-CoV-2 protease inhibitor was able to ameliorate the infection of kidney cells by SARS-CoV-2. Our results suggest that SARS-CoV-2 can directly infect kidney cells and induce cell injury with subsequent fibrosis. These data could explain both acute kidney injury in COVID-19 patients and the development of chronic kidney disease in long COVID.

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COVID-19 patients present tubulo-interstitial kidney fibrosis compared with controls

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SARS-CoV-2 infection stimulates profibrotic signaling in human kidney organoids

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SARS-CoV-2 infection can be inhibited by a protease blocker in human kidney organoids

PF-07059013: A Noncovalent Modulator of Hemoglobin for Treatment of Sickle Cell Disease

Sickle cell disease (SCD) is a genetic disorder caused by a single point mutation (β6 Glu → Val) on the β-chain of adult hemoglobin (HbA) that results in sickled hemoglobin (HbS). In the deoxygenated state, polymerization of HbS leads to sickling of red blood cells (RBC). Several downstream consequences of polymerization and RBC sickling include vaso-occlusion, hemolytic anemia, and stroke. We report the design of a noncovalent modulator of HbS, clinical candidate PF-07059013 (23). The seminal hit molecule was discovered by virtual screening and confirmed through a series of biochemical and biophysical studies. After a significant optimization effort, we arrived at 23, a compound that specifically binds to Hb with nanomolar affinity and displays strong partitioning into RBCs. In a 2-week multiple dose study using Townes SCD mice, 23 showed a 37.8% (±9.0%) reduction in sickling compared to vehicle treated mice. 23 (PF-07059013) has advanced to phase 1 clinical trials.

Modern advances in heterocyclic chemistry in drug discovery

New advances in synthetic methodologies that allow rapid access to a wide variety of functionalized heterocyclic compounds are of critical importance to the medicinal chemist as it provides the ability to expand the available drug-like chemical space and drive more efficient delivery of drug discovery programs. Furthermore, the development of robust synthetic routes that can readily generate bulk quantities of a desired compound help to accelerate the drug development process. While established synthetic methodologies are commonly utilized during the course of a drug discovery program, the development of innovative heterocyclic syntheses that allow for different bond forming strategies are having a significant impact in the pharmaceutical industry. This review will focus on recent applications of new methodologies in C-H activation, photoredox chemistry, borrowing hydrogen catalysis, multicomponent reactions, regio- and stereoselective syntheses, as well as other new, innovative general syntheses for the formation and functionalization of heterocycles that have helped drive project delivery. Additionally, the importance and value of collaborations between industry and academia in shaping the development of innovative synthetic approaches to functionalized heterocycles that are of greatest interest to the pharmaceutical industry will be highlighted.

Covalent Enzyme Inhibition through Fluorosulfate Modification of a Noncatalytic Serine Residue

Irreversible enzyme inhibitors and covalent chemical biology probes often utilize the reaction of a protein cysteine residue with an appropriately positioned electrophile (e.g., acrylamide) on the ligand template. However, cysteine residues are not always available for site-specific protein labeling, and therefore new approaches are needed to expand the toolkit of appropriate electrophiles ("warheads") that target alternative amino acids. We previously described the rational targeting of tyrosine residues in the active site of a protein (the mRNA decapping scavenger enzyme, DcpS) using inhibitors armed with a sulfonyl fluoride electrophile. These inhibitors subsequently enabled the development of clickable probe technology to measure drug-target occupancy in live cells. Here we describe a fluorosulfate-containing inhibitor (aryl fluorosulfate probe (FS-p1)) with excellent chemical and metabolic stability that reacts selectively with a noncatalytic serine residue in the same active site of DcpS as confirmed by peptide mapping experiments. Our results suggest that noncatalytic serine targeting using fluorosulfate electrophilic warheads could be a suitable strategy for the development of covalent inhibitor drugs and chemical probes.

Chemoselective Preparation of Clickable Aryl Sulfonyl Fluoride Monomers: A Toolbox of Highly Functionalized Intermediates for Chemical Biology Probe Synthesis

Sulfonyl fluoride (SF)-based activity probes have become important tools in chemical biology. Herein, exploiting the relative chemical stability of SF to carry out a number of unprecedented SF-sparing functional group manipulations, we report the chemoselective synthesis of a toolbox of highly functionalized aryl SF monomers that we used to quickly prepare SF chemical biology probes. In addition to SF, the monomers bear an embedded click handle (a terminal alkyne that can perform copper(I)-mediated azide-alkyne cycloaddition). The monomers can be used either as fragments to prepare clickable SF analogues of drugs (biologically active compounds) bearing an aryl ring or, alternatively, attached to drugs as minimalist clickable aryl SF substituents.

Rational targeting of active-site tyrosine residues using sulfonyl fluoride probes

This work describes the first rational targeting of tyrosine residues in a protein binding site by small-molecule covalent probes. Specific tyrosine residues in the active site of the mRNA-decapping scavenger enzyme DcpS were modified using reactive sulfonyl fluoride covalent inhibitors. Structure-based molecular design was used to create an alkyne-tagged probe bearing the sulfonyl fluoride warhead, thus enabling the efficient capture of the protein from a complex proteome. Use of the probe in competition experiments with a diaminoquinazoline DcpS inhibitor permitted the quantification of intracellular target occupancy. As a result, diaminoquinazoline upregulators of survival motor neuron protein that are used for the treatment of spinal muscular atrophy were confirmed as inhibitors of DcpS in human primary cells. This work illustrates the utility of sulfonyl fluoride probes designed to react with specific tyrosine residues of a protein and augments the chemical biology toolkit by these probes uses in target validation and molecular pharmacology.

A library approach to rapidly discover photoaffinity probes of the mRNA decapping scavenger enzyme DcpS

A photoaffinity library expedited the discovery of a site-specific DcpS probe.

On the importance of synthetic organic chemistry in drug discovery: reflections on the discovery of antidiabetic agent ertugliflozin

The discovery of antidiabetic agent ertugliflozin is described. In this article, emphasis is placed on the critical role that organic synthesis played in influencing our medicinal chemistry strategy.

Pharmacodynamic model of sodium-glucose transporter 2 (SGLT2) inhibition: implications for quantitative translational pharmacology

Sodium-glucose co-transporter-2 (SGLT2) inhibitors are an emerging class of agents for use in the treatment of type 2 diabetes mellitus (T2DM). Inhibition of SGLT2 leads to improved glycemic control through increased urinary glucose excretion (UGE). In this study, a biologically based pharmacokinetic/pharmacodynamic (PK/PD) model of SGLT2 inhibitor-mediated UGE was developed. The derived model was used to characterize the acute PK/PD relationship of the SGLT2 inhibitor, dapagliflozin, in rats. The quantitative translational pharmacology of dapagliflozin was examined through both prospective simulation and direct modeling of mean literature data obtained for dapagliflozin in healthy subjects. Prospective simulations provided time courses of UGE that were of consistent shape to clinical observations, but were modestly biased toward under prediction. Direct modeling provided an improved characterization of the data and precise parameter estimates which were reasonably consistent with those predicted from preclinical data. Overall, these results indicate that the acute clinical pharmacology of SGLT2 inhibitors in healthy subjects can be reasonably well predicted from preclinical data through rational accounting of species differences in pharmacokinetics, physiology, and SGLT2 pharmacology. Because these data can be generated at the earliest stages of drug discovery, the proposed model is useful in the design and development of novel SGLT2 inhibitors. In addition, this model is expected to serve as a useful foundation for future efforts to understand and predict the effects of SGLT2 inhibition under chronic administration and in other patient populations.

Activation of the G-protein-coupled receptor 119: a conformation-based hypothesis for understanding agonist response

The synthesis and properties of the bridged piperidine (oxaazabicyclo) compounds 8, 9, and 11 are described. A conformational analysis of these structures is compared with the representative GPR119 ligand 1. These results and the differences in agonist pharmacology are used to formulate a conformation-based hypothesis to understand activation of the GPR119 receptor. We also show for these structures that the agonist pharmacology in rat masks the important differences in human pharmacology.

C-Aryl glycoside inhibitors of SGLT2: Exploration of sugar modifications including C-5 spirocyclization

Modifications to the sugar portion of C-aryl glycoside sodium glucose transporter 2 (SGLT2) inhibitors were explored, including systematic deletion and modification of each of the glycoside hydroxyl groups. Based on results showing activity to be quite tolerant of structural change at the C-5 position, a series of novel C-5 spiro analogues was prepared. Some of these analogues exhibit low nanomolar potency versus SGLT2 and promote urinary glucose excretion (UGE) in rats. However, due to sub-optimal pharmacokinetic parameters (in particular half-life), predicted human doses did not meet criteria for further advancement.

Potent pyrimidinetrione-based inhibitors of MMP-13 with enhanced selectivity over MMP-14

Through the use of computational modeling, a series of pyrimidinetrione-based inhibitors of MMP-13 was designed based on a lead inhibitor identified through file screening. Incorporation of a biaryl ether moiety at the C-5 position of the pyrimidinetrione ring resulted in a dramatic enhancement of MMP-13 potency. Protein crystallography revealed that this moiety binds in the S(1)(') pocket of the enzyme. Optimization of the C-4 substituent of the terminal aromatic ring led to incorporation of selectivity versus MMP-14 (MT-1 MMP). Structure activity relationships of the biaryl ether substituent are presented as is pharmacokinetic data for a compound that meets our in vitro potency and selectivity goals.

Pyran-containing sulfonamide hydroxamic acids: potent MMP inhibitors that spare MMP-1

The SAR of a series of sterically hindered sulfonamide hydroxamic acids with relatively large P1' groups is described. The compounds typically spare MMP-1 while being potent inhibitors of MMP-13. The metabolically more stable compounds in the series contain either a monocyclic or bicyclic pyran ring adjacent to the hydroxamate group. Despite the sparing of MMP-1, pre-clinical and clinical studies revealed that fibrosis in rats and MSS in humans is still produced.

The glucocorticoid receptor: molecular mechanism and new therapeutic opportunities

Synthetic glucocorticoids are among the most effective anti-inflammatory drugs available. The activity of this drug class is mediated by the glucocorticoid receptor, a nuclear steroid receptor whose endogenous ligand is the adrenal hormone cortisol. Chronic glucocorticoid treatment is accompanied by serious side-effects, reflecting the symptoms of cortisol excess seen in Cushing's syndrome patients. During the past 50 years advances to this drug class have been limited largely to reducing systemic exposure through inhaled delivery and increasing glucocorticoid receptor selectivity. However, a safer oral drug for the treatment of conditions such as rheumatoid arthritis, inflammatory bowel disease, and transplant rejection, still represents a major unmet medical need. Over the past 20 years, mechanisms of glucocorticoid receptor action have been elucidated. Before the gene was even cloned, the glucocorticoid receptor was known to be a ligand-induced DNA binding protein. Identification of hormone response elements in the promoters of metabolic target genes in the liver provided a model for its broad activities. It was since revealed that much of its anti-inflammatory activity is not DNA-dependent after all, but instead is the result of a complex set of protein-protein interactions which lead to transcriptional inhibition of pro-inflammatory targets. Thus, a glucocorticoid receptor ligand that dissociates the DNA binding and protein interaction mediated activities is expected to show improved safety. This review will focus on the scientific advances, which impact the development of this hypothesis and will present a survey of current preclinical drug candidates employing this strategy.

Design and synthesis of 2-oxo-imidazolidine-4-carboxylic acid hydroxyamides as potent matrix metalloproteinase-13 inhibitors

A novel series of imidazolidinone-based matrix metalloproteinase (MMP) inhibitors was discovered by structural modification of pyrrolidinone la. Potent inhibition of MMP-13 was exhibited by the analogues having 4-(4-fluorophenoxy)phenyl (4a, IC50 = 3 nM) and 4-(naphth-2-yloxy)phenyl (4h, IC50 = 4 nM) as P1' groups.

Comparison of the transtrochanteric and posterior approaches for total hip replacement

One-hundred fifty-six consecutive total hip replacements through a lateral transtrochanteric approach were evaluated and compared to a closely matched group of 160 consecutive similar procedures via a posterior approach. The lateral approach did not have any dislocations and created a greater abductor lever arm. However, a 4.5% complication rate was related to the greater trochanter and degraded the result. The posterior approach provided a shorter operative time, required less blood replacement, and resulted in a shorter hospital stay. However a 4.4% incidence of dislocation decreased the rate of recovery and the final result. Since this early experience, an improved technique of reattaching the short external rotators had mitigated the problem of dislocations. Wound and systemic complications, postoperative results, radiographic findings and prosthetic positioning were not significantly different in comparable patients treated by the 2 surgical approaches.

Joint motion and surface contact area related to component position in total hip arthroplasty

A three-dimensional computer model of a total hip replacement was used to examine the relationship between the position of the components, the range of motion and the prosthetic joint contact area. Horizontal acetabular positions with small amounts of acetabular and femoral anteversion provide the largest contact areas, but result in limited joint movement. These data will allow surgeons to select implant positions that will provide the largest possible joint contact area for a given joint range of motion although these are conflicting goals. In some component positions a truncated spherical prosthetic head resulted in smaller contact areas than a completely spherical head.

Uncemented total hip arthroplasty using the CLS stem: a titanium alloy implant with a corundum blast finish. Results at a mean 6 years in a prospective study

An uncemented titanium alloy stem with a corundum blast finish and an uncemented titanium fibermetal mesh socket were implanted in a series of 57 hips. These prostheses were selected for use in the youngest, most active, and/or heaviest candidates for total hip arthroplasty. Fifty hips were available for study at a minimum 60 months. At a mean 6 years, 92% of the hips were rated good or excellent. The mean Harris hip score was 92. One patient experienced mild thigh pain. The corundum blast finish was associated with reliable implant stability. Survival analysis predicted a 96% rate of implant survival at 92 months. Loss of bone density was rated mild, minimal, or none in 88% of the hips. Three hips developed severe bone loss due to systemic disease. Polyethylene wear was measurable in 86% of the hips. Twenty hips developed focal proximal femoral bone erosions. One hip had endosteal cavitation distal to zone 7. The presence of proximal femoral erosions or endosteal cavitation correlated positively with the presence of measurable polyethylene wear. The limited and proximal distribution of femoral bone erosion despite evidence of extensive polyethylene wear suggested that bone apposition to the corundum blast finish resulted in a barrier to migration of wear debris.

Uncemented press-fit total hip arthroplasty using the Identifit custom-molding technique. A prospective minimum 2-year follow-up study

Fifty-three primary uncemented custom-molded Identifit (Depuy, Warsaw, IN) hip arthroplasties were evaluated prospectively at a mean follow-up period of 30 months. The custom technique provided the capability to reproduce the unique femoral offset, version, and height in each hip and to achieve high percentages of femoral canal fill. Surgical time for unilateral cases was a mean 153 minutes. Clinical results, however, were disappointing. Nine hips (17%) required stem revision for persistent thigh pain and limping. Of the remaining 44 hips, the mean Harris hip score was 83, and 20% experienced moderate to severe thigh pain and 50% had a limp. Radiographically, 65% of the stems had subsided and 27% had migrated into valgus. Survivorship analysis predicted an 80% stem survival rate at 43 months. A precise fit and fill of the femoral canal is not in itself sufficient for femoral implant stability in total hip arthroplasty surgery.

Discovery of the hemifumarate and (alpha-L-alanyloxy)methyl ether as prodrugs of an antirheumatic oxindole: prodrugs for the enolic OH group

Ether, ester, and carbonate derivatives of the antirheumatic oxindole 1 were prepared and screened as potential prodrugs of 1. This effort led to the discovery of the (alpha-L-alanyloxy)-methyl ether and hemifumarate derivatives of 1 which deliver the drug efficiently into the circulation of test animals, are stable in the solid state, and possess good stability in solution at low pH as required to ensure gastric stability. Success in achieving acceptable bioavailabilities of 1 across species (rats, dogs, and monkeys) followed the inclusion of ionizable functionality within the promoiety to compensate for masking the polar enolic OH group of the free drug. However, the introduction of ionizable functionality was often associated with decreased stability, as demonstrated by the hemisuccinate, hemiadipate, hemisuberate, and alpha-amino ester derivatives of 1 which could not be isolated. A clear exception was the hemifumarate derivative of 1 which was not only isolable but actually more stable at neutral pH than the nonionizable ester analogues. The solution and solid state stability of the hemifumarate, together with its activity as a prodrug of 1, suggests that hemifumarate be considered as an alternative to hemisuccinate as a prodrug derivative for alcohols, particularly in situations where solution state stability is an issue.

Reduction of intracellular pH by tenidap. Involvement of cellular anion transporters in the pH change

Tenidap [5-chloro-2,3-dihydro-3-(hydroxy-2-thienylmethylene)-2-oxo-1H- indole-1-carboxamide], a novel antirheumatic agent, produces a rapid and sustained intracellular acidification when applied to cells in culture. To investigate the mechanism by which this change in ionic homeostasis is achieved, the acidification activities of structural analogs of tenidap were determined, and the movements of [14C]tenidap into and out of cells were explored. The acidification activity of tenidap was enhanced by lowering extracellular pH, suggesting that the free acid species was required for this process. Consistent with this requirement, a non-acidic analog of tenidap did not produce a change in intracellular pH (pHi). In contrast, multihalogenated derivatives of tenidap produced greater changes in pHi than did tenidap, and one analog produced a transient acidification from which the cell recovered; this recovery, however, was blocked by an inhibitor of the Na+/H+ antiporter. Fibroblasts incubated with [14C]tenidap achieved within 5 min a level of cell-associated drug that remained constant during longer incubations. Simultaneous addition of the electrogenic ionophore valinomycin or the P-glycoprotein inhibitor 4-(3,4-dihydro-6,7-dimethoxy-2(1H)-isoquinolinyl)-N-[2-(3,4-dimethoxyphe nyl) ethyl]-6,7-dimethoxy-2-quinazolinamine (CP-100,356) caused a time- and concentration-dependent increase in the level of cell-associated [14C]tenidap; other agents tested did not promote this enhanced cellular accumulation. [14C]Tenidap accumulated by fibroblasts in the presence of CP-100,356 subsequently was released when these cells were placed in a tenidap- and CP-100,356-free medium. Importantly, several agents that are known to inhibit anion transport processes, including alpha-cyano-beta-(1-phenylindol-3-yl) acrylate, 5-nitro-2(3-phenylpropylamino)-benzoic acid, and meclofenamic acid, inhibited efflux of [14C]tenidap. In contrast, ethacrynic acid and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid did not impair the efflux process. Likewise, tenidap analogs that produced a sustained intracellular acidification blocked the efflux of [14C]tenidap, but non-acidifying species did not. These data suggest that movements of tenidap into and/or out of cells is a facilitated process subject to pharmacological intervention. Together, the structural selectivity of the acidification response and the evidence of facilitated transport suggest that the pHi modulating activity of tenidap is dependent on its unique physicochemical properties. Due to the dependence of these physicochemical properties on environmental and cellular conditions, in vivo expression of the acidification activity is likely to occur only within restricted environments that favor this tenidap-induced process.

Thermal expansion modular femoral head extractor for revision total hip arthroplasty

Removal of a prosthetic modular femoral head is sometimes desirable during revision hip arthroplasty. A femoral head extractor was designed to heat and expand the prosthetic femoral head, apply a gentle distraction load, and remove the femoral head without injury to the femoral neck, taper, or bone-prosthesis interface. The device was used clinically in six hip revision cases. In five hips with cobalt-chrome heads and titanium alloy tapers, femoral heads were removed successfully; femoral fixation was maintained and femoral components were not visibly damaged. In the sixth case, the female portion of the taper junction was contained in a long femoral head sleeve. Heating the ball did not adequately expand the sleeve to allow easy ball removal.

Titanium contamination of recycled Cell Saver blood in revision hip arthroplasty

The use of Cell Saver blood during revision hip arthroplasty has many benefits, both medical and economic. After a review of the current literature, to our knowledge, no case of metallic debris has been reported in the blood after complete treatment with the Haemonetics Cell Saver (Braintree, MA) and appropriate filter system. A case of total hip revision of a loose, cemented acetabular component with a commercially pure titanium metal backing and a titanium alloy plasma-spray textured surface was undertaken. The titanium alloy femoral component was not visibly loose and was not revised. The joint lining tissues were black. Throughout the procedure, the operative site was suctioned with a double-lumen heparinized catheter that delivered blood and other materials to a Haemonetics Cell Saver 3 Plus. The reservoir and filter unit used were the compatible Bentley BCR-3500 (Baxter, Irvine, CA), a system capable of filtering particulates down to 20 microns. Prior to infusion of the salvaged blood, many large black clumps of material were observed mixed in the blood. Some measured 10 x 5 x 5 mm and could easily be seen macroscopically. Light microscopy demonstrated red blood cells with intermixed neutrophils, and black foreign material scattered as separate particles and within the cytoplasm of the scattered histiocytes. Energy dispersive analysis of the black material confirmed the composition as primarily titanium with minute quantities of copper, iron, phosphorous, and sulfur. A scanning electron photomicrograph of one of the specimens demonstrated a large conglomerate, approximately 2,000 microns in diameter, composed primarily of titanium and organic material.(ABSTRACT TRUNCATED AT 250 WORDS)

Hip arthroplasty using the cementless CLS stem. A 2--4-year experience

Fifty-one Cementless Spotorno (CLS, Protek A. G. Berne) stems were implanted in 43 patients with either a Harris Galante (Zimmer, Warsaw, IN) socket or bipolar head. Patients were evaluated at a mean of 31 months. Eighty percent of the hips were in patients who were less than 50 years of age or weighed more than 80 kg. The CLS stem achieved initial stability by wedging a proximally fluted, straight stem into a retained bed of femoral trabecular and cortical bone. Distal canal fill was avoided. The postoperative mean Harris hip score was 95. Eighty percent of the hips were rated excellent, 16% good, 2% fair, and 2% poor. No stem required revision. Six percent had slight, occasional thigh pain. No patient had mild, moderate, or severe thigh pain. Six percent had a limp related to the operated hip. Fifty-three percent of the hips developed a radiographic appearance of bone apposition at the stem tip. Fifty-five percent of the hips had some reduction in proximal bone density. These changes suggested that as bone remodeling occurred, the initial proximal load transfer situation expected from the CLS stem design changed to include some distal load transfer resulting in proximal stress shielding. Ninety-four percent of the hips had either no change in femoral bone density or only patchy loss of density isolated to zone 7. A high dislocation rate was attributed to an unfavorable head-to-neck diameter ratio, a valgus neck shaft angle, and a patient population capable of excellent hip motion.