This is a phase 1, randomized, double-blind, placebo-controlled, SAD and MAD study in healthy adult volunteers. DGX-001 is a peptide being investigated for the treatment of the major depressive disorder. This study will examine the safety and tolerability of increasing doses of DGX-001 and, in an exploratory way, potential moderators and functional markers of its activity.

The study will be conducted in three parts, Part 1 consisting of SAD cohorts and Part 2 consisting of MAD cohorts and Part 3 consisting of one cohorts of stress exposure resilience panel. In Part 1, approximately 32 adult healthy volunteers will be enrolled sequentially into 1 of 4 single-dose cohorts and will be randomized to receive either a dose of DGX-001 or a placebo. In Part 2, approximately 24 adult healthy volunteers will be enrolled into 1 of 3 multiple-dose cohorts. An adaptive dose-escalation schedule will be employed for both the SAD and MAD parts of the study. In Part 3, 14 subjects will be enrolled in 1 cohorts to further explore the pharmacodynamic effect of DGX-001 under a physiological challenge.

Inclusion Criteria:

1. Male or female healthy adult volunteers between 18 to 65 years of age (Both inclusive).
2. The subject's BMI is between 18 and 32 kg/m2.
3. Female subjects with childbearing potential must have a negative serum pregnancy test.
4. The subject is medically healthy with no clinically significant or relevant abnormalities in medical history, physical exam, vital signs, electrocardiogram (ECG), and laboratory evaluations (hematology, chemistry, and urinalysis) as assessed by the Investigator.

Exclusion Criteria:

1. The subject has a current or recurrent disease that could affect the action, absorption or disposition of the investigational medicinal product or could affect clinical or laboratory assessments.
2. The subject has abnormal renal function test ( <60mL/min, i.e., GFR by Cockroft/Gault) at screening or baseline.
3. The subject has evidence of Gilbert's Syndrome or abnormal liver function test (LFTs >1.5x ULN) at screening or baseline.
4. The subject has had a cholecystectomy or a history of cholecystitis.
5. The subject has clinically significant 12-lead ECG abnormalities, including QTc of 450ms for males and 470ms for females (average of triplicate measures) for any pre-randomization ECG assessment.
6. The subject has a current or relevant history of physical or psychiatric illness.
7. The subject has a documented history of HIV antibody or tested positive for hepatitis B surface antigen (HBsAg) or Hepatitis C virus (HCV) antibody at screening.
8. The subject received an investigational agent within the last 30 days prior to Screening or five half-lives (if known) prior to Screening.
9. The subject has a history of alcohol or other substance abuse within the 12 months prior to dosing.
10. The subject is currently using any medication (including over-the-counter [OTC], herbal or homeopathic preparations), except for hormonal replacement therapy or hormonal contraceptives, that in the opinion of the investigator can not be discontinued and avoided for four weeks before the first dose throughout the study period.

Double-blind